Bio

Clinical Focus


  • Orthopaedic Surgery
  • Revision Total Hip and Knee Replacement
  • Evaluation of Failed Joint Replacement
  • Unicompartmental Knee Replacement
  • Primary Total Hip and Knee Replacement

Academic Appointments


Administrative Appointments


  • Chair, Stanford University School of Medicine - Orthopaedic Surgery (2004 - Present)

Honors & Awards


  • Guest Speaker, 3rd CUHK International Symposium on Stem Cell Biology and Regenerative Medicine, Hong Kong (2013)
  • Guest Speaker, 8th International Congress of Chinese Orthopaedic Association, Beijing, China (2013)
  • Guest Speaker, The AOA 73rd Annual Scientific Meeting, Darwin, Australia (2013)
  • Guest Speaker, The Great Debate, Raising Standards in Hip and Knee Arthroplasty, London, UK (2013)
  • Presidential Guest Speaker, 2012 Annual Fall Congress of the Korean Orthopaedic Association. Seoul, Korea (2012)
  • Guest Speaker, 2012 Asia Pacific Insall Legacy Symp and Annual Mtg of the Thai Hip and Knee Soc.,Tua Hin,Thailand (2012)
  • Guest Speaker, The 1st Bangkok Hospital, Stanford Hip and Knee Intensive Course, Bangkok, Thailand (2012)
  • Guest Speaker, The 2nd International Symposium on Musculoskeletal System and Pain,Sapporo, Japan (2012)
  • Guest Speaker, The Great Debate, Optimizing Outcomes of Hip and Knee Arthroplasty, London, UK. (2012)
  • Guest Speaker, 67th Panhellenic Orthopaedic Congress, Athens, Greece (2011)
  • Invited Lecturer, SICOT 2011 XXV Triennial World Congress, Prague, Czech Republic (2011)
  • Visiting Professor, Columbia University Orthopaedic Resident Graduation, New York, NY (2011)
  • Guest Speaker, 55th Annual Meeting of Korean Hip Society (2011)
  • Visiting Professor, Columbia University, New York, NY (2011)
  • Presidential Guest Speaker, 41st Annual Japanese Society for Replacement Arthroplasty (2011)
  • Guest Speaker, Combined 33rd SOA- 30th AOA Annual Congress (2010)
  • AAHKS President's Honor Roll, Gold Level, American Association of Hip and Knee Surgeons (2010)
  • Achievement Award, American Academy of Orthopaedic Surgeons (2010)
  • The Otto Aufranc Award, The Hip Society (2010)
  • J. Albert Key Visiting Professor, Washington University, St. Louis, MO (2010)
  • Visiting Professor, Turkish National Congress, Cesme, Irmir, Turkey (2009)
  • Visiting Professor, University of Toronto, Ontario, Canada (2009)
  • Presidential Guest Speaker, 82nd Japanese Orthopaedic Association, Fukuoka, Japan (2009)
  • Visiting Professor, University of California, Los Angeles (2009)
  • Visiting Professor, UT Southwestern Medical Center,Texas (2008)
  • Larry Matthew, Visiting Professor, University of Michigan (2007)
  • Marshall Urist Award, Association of Bone and Joint Surgeons (2007)
  • Presidential Guest Speaker, Japanese Orthopaedic Association (2006)
  • Elsbach-Richards Professor and Chairman, Stanford University School of Medicine (2005)
  • Visiting Professor, University of California-LA, Los Angeles, CA (2004)
  • Visiting Professor, Columbia University, New York, NY (2003)
  • Alumni visiting Professor, University of Utah, Salt Lake City, UT (2003)
  • Presidential Guest Speaker, Japanese Hip Society, Sapporo, Japan (2003)
  • Presidential Guest Speaker, Georgia Orthopaedic Society, Sea Island, Georgia (2002)
  • Presidential Guest Speaker, Georgia Orthopaedic Society, Sea Island, Georgia (2002)
  • Presidential Guest Speaker, Florida Orthopaedic Society, Orlando, FL (2002)
  • First Annual William H. Harris Lecture, Massachusetts General Hospital, Boston, MA (2001)
  • Presidential Guest Speaker, Japanese Orthopaedic Association, Chiba, Japan (2001)
  • Presidential Guest Speaker, Ontario Orthopaedic Association, Toronto, Canada (2000)
  • Presidential Guest Speaker, Chinese Orthopaedic Association, Beijing, China (2000)
  • Visiting Professor, University of Michigan, Ann Arbor, MI (2000)
  • Presidential Guest Speaker, Japanese Orthopaedic Association, Kobe, Japan (2000)
  • Visiting Professor, Brown University School of Medicine (2000)
  • Pasternak Visiting Professor, Hartford Hospital, University of Connecticut (1999)
  • Presidential Guest Speaker, Korean Orthopaedic Association (1999)
  • Visiting Professor, Keimyung University, Korea (1999)
  • Presiential Guest Speaker, Korean Orthopaedic Research Society (1999)
  • Visiting Professor, Kyung-Pok National Univrsity, Korea (1999)
  • Presidential Guest Speaker, Republic of China Orthopaedic Association, Taiwan (1999)
  • The Charles and Joanne Knight Distinguished Chair in Orthopaedic Surgery, Washington Unviersity School of Medicine (1998)
  • Visiting Professor, Asahikawa Medical College (1998)
  • Presidential Guest Speaker, Japanese Orthopaedic Association (1997)
  • Visiting Professor, Catholic University, Seoul, Korea (1997)
  • The American-British-Canadian (ABC) Traveling Fellowship Award, American Orthopaedic Association (1997)
  • Presidential Guest Speaker, Singapore Orthopaedic Association (1996)
  • Presidential Guest Speaker, Korean Hip Society (1996)
  • Presidential Guest Speaker, Northern California Chapter of the Western Orthopaedic Association (1996)
  • Otto Aufranc Award - Femoral Bone Remodeling after Total Hip Arthroplasty, Hip Society (1996)
  • The North American Traveling Fellowship Award, American Orthopaedic Association (1991)
  • The Frank Stinchfield Award of the Hip Society, Hip Society (1989)
  • The William H. Harris, MD Fellowship, Hip Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School (1988)
  • Theta Delta Chi Award for Leadership and Scholarship, Stanford University (1978)

Professional Education


  • Medical Education:Columbia University College of Physicians and Surgeons (1983) NY
  • Residency:Stanford University Medical Center (1988) CA
  • Board Certification: Orthopaedic Surgery, American Board of Orthopaedic Surgery (1991)
  • Fellowship:Massachusetts General Hospital/Harvard Medical (1989) MA
  • Internship:Stanford University Medical Center (1984) CA
  • BA, Stanford University, Psychology (1979)

Research & Scholarship

Current Research and Scholarly Interests


Dr. Maloney is nationally and internationally recognized for his contributions to the improved understanding of the causes of failure of surgical joint replacement. For example, he established a critical link between polyethylene wear debris and bony erosion, with resulting significant changes in the materials and design strategies of joint replacement surgery. More recently, he has shown that wear debris particles are coated in vivo with human proteins, such as albumin; this observation has notably improved the validity of in vitro investigation in this area. His research in the area of joint replacement has twice won awards from the Hip Society. Dr. Maloney is a member of the Central Program Committee of the American Academy of Orthopedic Surgeons, and he chairs multiple additional national committees, including the National Hip and Knee Registry Work Group of the American Academy of Orthopedic Surgeons, the Awards Committee of the Association of Bone and Joint Surgeons, the Awards and Publications Committee of the Hip Society, and the ABC Exchange Fellowship Subcommittee of the American Orthopedic Association. He has been a Visiting Professor to numerous universities and institutions throughout the United States and Asia.

Teaching

2013-14 Courses


Postdoctoral Advisees


Publications

Journal Articles


  • Commentary: Is the hip bone connected to the spine bone? SPINE JOURNAL Huddleston, J. I., Maloney, W. J. 2012; 12 (5): 370-371

    Abstract

    COMMENTARY ON: Prather H, Van Dillen LR, Kymes SM, et al. Impact of coexistent lumbar spine disorders on clinical outcomes and physician charges associated with total hip arthroplasty. Spine J 2012;12:363-9 (in this issue).

    View details for DOI 10.1016/j.spinee.2012.05.002

    View details for Web of Science ID 000305298300002

    View details for PubMedID 22698149

  • Decreased Length of Stay After TKA Is Not Associated With Increased Readmission Rates in a National Medicare Sample CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Vorhies, J. S., Wang, Y., Herndon, J. H., Maloney, W. J., Huddleston, J. I. 2012; 470 (1): 166-171

    Abstract

    There is a trend toward decreasing length of hospital stay (LOS) after TKA although it is unclear whether this trend is detrimental to the overall postoperative course. Such information is important for future decisions related to cost containment.We determined whether decreases in LOS after TKA are associated with increases in readmission rates.We retrospectively reviewed the rates and reasons for readmission and LOS for 4057 Medicare TKA patients from 2002 to 2007. We abstracted data from the Medicare Patient Safety Monitoring System. Hierarchical generalized linear modeling was used to assess the odds of changing readmission rates and LOS over time, controlling for changes in patient demographic and clinical variables.The overall readmission rate in the 30 days after discharge was 228/4057 (5.6%). The 10 most common reasons for readmission were congestive heart failure (20.4%), chronic ischemic heart disease (13.9%), cardiac dysrhythmias (12.5%), pneumonia (10.8%), osteoarthrosis (9.4%), general symptoms (7.4%), acute myocardial infarction (7.0%), care involving other specified rehabilitation procedure (6.3%), diabetes mellitus (6.3%), and disorders of fluid, electrolyte, and acid-base balance (5.9%); the top 10 causes did not include venous thromboembolism syndromes. We found no difference in the readmission rate between the periods 2002-2004 (5.5%) and 2005-2007 (5.8%) but a reduction in LOS between the periods 2002-2004 (4.1 ± 2.0 days) and 2005-2007 (3.8 ± 1.7 days).The most common causes for readmission were cardiac-related. A reduction in LOS was not associated with an increase in the readmission rate in this sample. Optimization of cardiac status before discharge and routine primary care physician followup may lead to lower readmission rates.

    View details for DOI 10.1007/s11999-011-1957-0

    View details for Web of Science ID 000298103100021

    View details for PubMedID 21720934

  • Human bone marrow hematopoietic stem cells are increased in frequency and myeloid-biased with age PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Pang, W. W., Price, E. A., Sahoo, D., Beerman, I., Maloney, W. J., Rossi, D. J., Schrier, S. L., Weissman, I. L. 2011; 108 (50): 20012-20017

    Abstract

    In the human hematopoietic system, aging is associated with decreased bone marrow cellularity, decreased adaptive immune system function, and increased incidence of anemia and other hematological disorders and malignancies. Recent studies in mice suggest that changes within the hematopoietic stem cell (HSC) population during aging contribute significantly to the manifestation of these age-associated hematopoietic pathologies. Though the mouse HSC population has been shown to change both quantitatively and functionally with age, changes in the human HSC and progenitor cell populations during aging have been incompletely characterized. To elucidate the properties of an aged human hematopoietic system that may predispose to age-associated hematopoietic dysfunction, we evaluated immunophenotypic HSC and other hematopoietic progenitor populations from healthy, hematologically normal young and elderly human bone marrow samples. We found that aged immunophenotypic human HSC increase in frequency, are less quiescent, and exhibit myeloid-biased differentiation potential compared with young HSC. Gene expression profiling revealed that aged immunophenotypic human HSC transcriptionally up-regulate genes associated with cell cycle, myeloid lineage specification, and myeloid malignancies. These age-associated alterations in the frequency, developmental potential, and gene expression profile of human HSC are similar to those changes observed in mouse HSC, suggesting that hematopoietic aging is an evolutionarily conserved process.

    View details for DOI 10.1073/pnas.1116110108

    View details for Web of Science ID 000298034800040

    View details for PubMedID 22123971

  • Readmission and Length of Stay After Total Hip Arthroplasty in a National Medicare Sample JOURNAL OF ARTHROPLASTY Vorhies, J. S., Wang, Y., Herndon, J., Maloney, W., Huddleston, J. I. 2011; 26 (6): 119-123

    Abstract

    Evaluation of hospital readmissions after total hip arthroplasty may help improve patient safety and cost reduction. This study investigates the rates and reasons for readmission as well as length of hospital stay (LOS) for 1802 total hip arthroplasty patients from 2002 to 2007. Data were abstracted from the Medicare Patient Safety Monitoring System. The overall 30-day rate of readmission was 6.8%. There was no difference in readmission rate from 2002 to 2004 (7.1%) to 2005 to 2007 (6.3%) (odds ratio, 0.90; 95% confidence interval, 0.63-1.30; P = .58). The overall mean LOS was 4.2 ± 2.2 days. There was a significant reduction in LOS from 2002 to 2004 (4.4 ± 2.5 days) to 2005 to 2007 (3.8 ± 1.7 days) (odds ratio, 1.28; 95% confidence interval, 1.25-1.31; P < .0001). The most common causes for readmission were cardiac related. A reduction in LOS was not associated with an increase in the rate of readmission in this sample. Efforts to optimize cardiac status before discharge may lead to lower rates of readmission in the future.

    View details for DOI 10.1016/j.arth.2011.04.036

    View details for Web of Science ID 000294393000023

    View details for PubMedID 21723700

  • Effects of Intermittent Hydrostatic Pressure and BMP-2 on Osteoarthritic Human Chondrocyte Metabolism In Vitro JOURNAL OF ORTHOPAEDIC RESEARCH Smith, R. L., Lindsey, D. P., Dhulipala, L., Harris, A. H., Goodman, S. B., Maloney, W. J. 2011; 29 (3): 361-368

    Abstract

    This study examined effects of intermittent hydrostatic pressure (IHP) and a chondrogenic growth factor, bone morphogenetic protein-2 (BMP-2), on anabolic, catabolic, and other metabolic markers in human osteoarthritic (OA) chondrocytes in vitro.Articular chondrocytes, isolated from femoral OA cartilage and maintained in high-density monolayer culture, were examined for effects of BMP-2 and IHP on gene expression of matrix-associated proteins (aggrecan, type II collagen, and SOX9) and catabolic matrix metalloproteinases (MMP-2 and MMP-3) and culture medium levels of the metabolic markers MMP-2, nitric oxide (NO), and glycosaminoglycan (GAG). The results were analyzed using a mixed linear regression model to investigate the effects of load and growth factor concentration.IHP and BMP-2 modulated OA chondrocyte metabolism in accordance with growth factor concentration independently, without evidence of synergism or antagonism. Each type of stimulus acted independently on anabolic matrix gene expression. Type II collagen and SOX9 gene expression were stimulated by both IHP and BMP-2 whereas aggrecan was increased only by BMP-2. IHP exhibited a trend to decrease MMP-2 gene expression as a catabolic marker whereas BMP-2 did not. NO production was increased by addition of BMP-2 and IHP exhibited a trend for increased levels. GAG production was increased by BMP-2.This study confirmed the hypothesis that human OA chondrocytes respond to a specific type of mechanical load, IHP, through enhanced articular cartilage macromolecule gene expression and that IHP, in combination with a chondrogenic growth factor BMP-2, additively enhanced matrix gene expression without interactive effects.

    View details for DOI 10.1002/jor.21250

    View details for Web of Science ID 000287173500009

    View details for PubMedID 20882590

  • Effects of Tensile Strain and Fluid Flow on Osteoarthritic Human Chondrocyte Metabolism In Vitro JOURNAL OF ORTHOPAEDIC RESEARCH Mawatari, T., Lindsey, D. P., Harris, A. H., Goodman, S. B., Maloney, W. J., Smith, R. L. 2010; 28 (7): 907-913

    Abstract

    This study examined the hypothesis that tensile strain and fluid flow differentially influence osteoarthritic human chondrocyte metabolism. Primary high-density monolayer chondrocytes cultures were exposed to varying magnitudes of tensile strain and fluid-flow using a four-point bending system. Metabolic changes were quantified by real-time PCR measurement of aggrecan, IL-6, SOX-9, and type II collagen gene expression, and by determination of nitric oxide levels in the culture medium. A linear regression model was used to investigate the roles of strain, fluid flow, and their interaction on metabolic activity. Aggrecan, type II collagen, and SOX9 mRNA expression were negatively correlated to increases in applied strain and fluid flow. An effect of the strain on the induction of nitric oxide release and IL-6 gene expression varied by level of fluid flow (and visa versa). This interaction between strain and fluid flow was negative for nitric oxide and positive for IL-6. These results confirm that articular chondrocyte metabolism is responsive to tensile strain and fluid flow under in vitro loading conditions. Although the articular chondrocytes reacted to the mechanically applied stress, it was notable that there was a differential effect of tensile strain and fluid flow on anabolic and catabolic markers.

    View details for DOI 10.1002/jor.21085

    View details for Web of Science ID 000278654500011

    View details for PubMedID 20063382

  • In Vivo Femoral Head Damage and Its Effect on Polyethylene Wear JOURNAL OF ARTHROPLASTY Ito, H., Maloney, C. M., Crowninshield, R. D., Clohisy, J. C., McDonald, D. J., Maloney, W. J. 2010; 25 (2): 302-308

    Abstract

    The purposes of this study were to determine the spectrum of femoral head damage in patients undergoing revision total hip arthroplasty and to determine the impact of that damage on polyethylene wear. One hundred eight consecutive modular metal femoral heads were retrieved at revision surgery. The mean roughness (Ra) value was 0.18 +/- 0.18 microm. The roughest femoral heads (mean Ra, 0.56 microm) were from retrievals correlated with mode 2 wear (recurrent dislocation and complete wear through of the polyethylene liner). Five million cycles of wear tests were performed using retrieved femoral heads against both new conventional and highly cross-linked polyethylene. The mean wear rate of conventional polyethylene was 15.9 +/- 4.3 mg and that of highly cross-linked polyethylene was 0.04 +/- 0.14 mg per 1 million cycles (P < .001). Highly cross-linked polyethylene was more resistant to wear than conventional polyethylene, even when mated against roughened femoral heads.

    View details for DOI 10.1016/j.arth.2009.01.010

    View details for Web of Science ID 000277580900023

    View details for PubMedID 19201153

  • Adverse Events After Total Knee Arthroplasty A National Medicare Study JOURNAL OF ARTHROPLASTY Huddleston, J. I., Maloney, W. J., Wang, Y., Verzier, N., Hunt, D. R., Herndon, J. H. 2009; 24 (6): 95-100

    Abstract

    Adverse events from 2033 total knee arthroplasty patients were documented by nonphysician abstractors. The annual rate of adverse events from 2002 to 2004 was 9.2%, 6.4%, and 5.8%, respectively. Congestive heart failure (odds ratio, 2.1; 95% confidence interval, 1.2-3.5; P < .01) and chronic obstructive pulmonary disease (odds ratio, 1.8; 95% confidence interval, 1.2-2.7; P < .01) were associated with a significantly increased risk of experiencing any adverse event during the index hospitalization. The 30-day postprocedure rate of readmission for all causes was 5.5%. Experiencing an adverse event during the index hospitalization increased the length of stay (P < .001). The rate of symptomatic venous thromboembolism 30 days postprocedure was 1.7%. The 30-day postprocedure mortality rate was 0.3%. Experiencing any adverse event was associated with an increased 30-day postprocedure mortality (P < .001). Compared with previous studies of Medicare claims, these data reveal a substantial decrease in the mortality rate, an increased readmission rate, and no substantial change in the rate of venous thromboembolism.

    View details for DOI 10.1016/j.arth.2009.05.001

    View details for Web of Science ID 000269607800020

    View details for PubMedID 19577884

  • THA with Highly Cross-linked Polyethylene in Patients 50 Years or Younger CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Shia, D. S., Clohisy, J. C., Schinsky, M. F., Martell, J. M., Maloney, W. J. 2009; 467 (8): 2059-2065

    Abstract

    Highly cross-linked polyethylene has been associated with low in vitro wear, but also has decreased in vitro ultimate yield strength. We therefore asked whether highly cross-linked polyethylene would result in lower outcome scores, wear, or early failure in a young patient population. Seventy THAs in 64 patients were performed using a highly cross-linked (electron beam-irradiated to 9 Mrads) acetabular liner and a cobalt-chrome femoral head. The average age of the patients at surgery was 41 years (range, 19-50 years). The minimum followup was 2.4 years (average, 4 years; range, 2.4-6.5 years). We recorded demographic and clinical data, including Harris hip score. Polyethylene wear measurements were analyzed with a validated, computer-assisted, edge detection method. The average Harris hip score improved from 53 to 92 at last followup. There was no evidence of acetabular or femoral loss of fixation, subsidence, or loosening. Linear wear was undetectable at this followup interval. No patient experienced catastrophic failure or underwent revision surgery. These data show low polyethylene wear rates and no catastrophic failures at early followup in a young patient cohort.Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

    View details for DOI 10.1007/s11999-008-0697-2

    View details for Web of Science ID 000267779100019

    View details for PubMedID 19142685

  • Minimal Incision Surgery as a Risk Factor for Early Failure of Total Knee Arthroplasty JOURNAL OF ARTHROPLASTY Barrack, R. L., Barnes, C. L., Burnett, R. S., Miller, D., Clohisy, J. C., Maloney, W. J. 2009; 24 (4): 489-498

    Abstract

    A consecutive series of revision total knee arthroplasty (TKA) performed at 3 centers by 5 surgeons for a 3-year period was reviewed. Revisions performed for infection and rerevisions were excluded. Review of clinical and radiographic data determined incision type, sex, age, time to revision, and primary diagnosis at time of revision. Two-hundred thirty-seven first-time revision TKAs were performed, of which 44 (18.6%) had been a minimal incision surgery (MIS) primary TKA and 193 (81.4%) had been a standard primary TKA. Patients with MIS were younger (62.1 vs 66.2 years, P = .02). Most striking was the difference in time to revision, which was significantly shorter for the MIS group (14.8 vs 80 months, P < .001). Minimal incision surgery TKA accounted for a substantial percentage of revision TKA in recent years at these centers. The high prevalence of MIS failures occurring within 24 months is disturbing and warrants further investigation.

    View details for DOI 10.1016/j.arth.2009.02.004

    View details for Web of Science ID 000266846500001

    View details for PubMedID 19339153

  • Averaging Different Alignment Axes Improves Femoral Rotational Alignment in Computer-Navigated Total Knee Arthroplasty JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Siston, R. A., Cromie, M. J., Gold, G. E., Goodman, S. B., Delp, S. L., Maloney, W. J., Giori, N. J. 2008; 90A (10): 2098-2104

    Abstract

    Computer navigation systems generally establish the rotational alignment axis of the femoral component on the basis of user-defined anatomic landmarks. However, navigation systems can also record knee kinematics and average alignment axes established with multiple techniques. We hypothesized that establishing femoral rotational alignment with the use of kinematic techniques is more accurate and precise (repeatable) than the use of anatomic techniques and that establishing femoral rotational alignment by averaging the results of different alignment techniques is more accurate and precise than the use of a single technique.Twelve orthopaedic surgeons used three anatomic and two kinematic alignment techniques to establish femoral rotational alignment axes in a series of nine cadaver knees. The axes derived with the individual anatomic and kinematic techniques as well as the axes derived with six combination techniques--i.e., those involving averaging of the alignments established with two of the individual techniques--were compared against a reference axis established with computed tomography images of each femur.The kinematic methods were not more accurate (did not have smaller mean errors) or more precise (repeatable) than the anatomic techniques. The combination techniques were accurate (five of the six had a mean error of <5 degrees ) and significantly more precise than all but one of the single methods. The percentage of measurements with <5 degrees of error as compared with the reference epicondylar axis was 37% for the individual anatomic techniques, 30% for the individual kinematic techniques, and 58% for the combination techniques.Averaging the results of kinematic and anatomic techniques, which is possible with computer navigation systems, appears to improve the accuracy of rotational alignment of the femoral component. The number of rotational alignment outliers was reduced when combination techniques were used; however, they are still a problem and continued improvement in methods to accurately establish rotation of the femoral component in total knee arthroplasty is needed.

    View details for DOI 10.2106/JBJS.G.00996

    View details for Web of Science ID 000259873300006

  • Implementation of the American Society of Anesthesiologists Physical Status classification system in periodontal practice JOURNAL OF PERIODONTOLOGY Maloney, W. J., Weinberg, M. A. 2008; 79 (7): 1124-1126

    Abstract

    The American Society of Anesthesiologists Physical Status (ASA-PS) classification is a preoperative rating given to each patient by an anesthesia provider with the sole purpose of assessing the physical state of the patient before anesthesia is administered. It was designed originally as a standardized way for dentists and physicians to convey information about the patient's overall health status and allow outcomes to be stratified by a global assessment of their severity of illness. However, in practice, the ASA-PS classification is often misused as a measure of operative risk, which is the basis of much criticism. Modification of periodontal treatment may be necessary in certain medically complex patients. The ASA-PS classification serves an integral part of risk assessment in determining how a patient should be managed by the periodontist. It should be incorporated into all periodontal practices. Medical assessment of patients has become an essential part of dentistry, as even the most common medical problems may require modifications to routine periodontal care. Periodontists must assess and manage patients for underlying medical conditions and are required to provide dental care to a diversity of medically complex patients. Today many patients in a periodontal practice have multiple medical conditions and are taking many medications. It is more difficult to manage these types of patients, and proper assessment of their physical status is an important part of clinical practice. The ASA-PS classification system is a valuable assessment tool that subjectively categorizes patients into subgroups by preoperative physical fitness prior to administering anesthesia.

    View details for DOI 10.1902/jop.2008.070625

    View details for Web of Science ID 000257643600002

    View details for PubMedID 18597592

  • Orthopedic surgery core curriculum hip and knee reconstruction CANADIAN JOURNAL OF SURGERY Wadey, V. M., Maloney, W. J., Dev, P., Walker, D. 2008; 51 (2): 135-141

    Abstract

    To develop a core curriculum for orthopedic surgery and to conduct a national survey to assess the importance of 281 curriculum items. Attention was focused on 55 topics pertaining to hip and knee reconstruction.A 281-item curriculum was developed. We completed a content review and cross-sectional survey of a random selection of orthopedic surgeons whose primary affiliation was nonuniversity. We analyzed the data descriptively and quantitatively, using histograms, a modified Hotelling's T2 statistic with the p value determined by a permutation test, and the Benjamini- Hochberg/Yekutieli procedure. Our analyses assumed that each respondent answered questions independently of the answers of any other respondent but that the answers to different questions by the same respondent might be dependent.Of 156 orthopedic surgeons, 131 (84%) participated in this study. Of 55 items ranked by all respondents, 42 received an average mean score greater than 3.5/4.0, and 51 received an average mean score equal to or greater than 3.0/40 (the standard deviation for each item ranged from 0.00 to 0.08), suggesting that 92.7% of the items are important or probably important to know by the end of residency.This study demonstrates agreement that it is important to include 92.7% of the items that pertain to hip and knee reconstruction in a core curriculum for orthopedic surgery. Residency training programs may need to ensure that appropriate educational opportunities focusing on complex primary and revision surgery are available to meet the future needs of orthopedic surgeons whose primary affiliation is nonuniversity.

    View details for Web of Science ID 000254552400010

    View details for PubMedID 18377755

  • Highly cross-linked polyethylene bearing surfaces in total hip arthroplasty. Journal of surgical orthopaedic advances Atienza, C., Maloney, W. J. 2008; 17 (1): 27-33

    Abstract

    Polyethylene wear-induced osteolysis is the most significant primary factor limiting the life span of total joint arthroplasty. To reduce ultra-high-molecular-weight polyethylene (UHMWPE) particulate wear debris, highly cross-linked polyethylene (HXPE) bearings have been introduced in total hip arthroplasty (THA). In vitro hip simulator wear studies with HXPE have demonstrated a decrease in volumetric wear at the hip by 42% to 100% when compared with conventional metal-on-polyethylene bearings. Early to intermediate clinical results suggest that the in vivo wear properties of HXPE products are superior to those of conventional UHMWPE. Second-generation HXPE materials that utilize alternate cross-linking and free radical quenching techniques have been developed and propose to further minimize wear and oxidation.

    View details for PubMedID 18284901

  • Modified posterior approach total to hip arthroplasty to enhance joint stability CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Kim, Y. S., Kwon, S. Y., Sun, D. H., Han, S. K., Maloney, W. J. 2008; 466 (2): 294-299

    Abstract

    We modified the posterior approach by preserving the external rotator muscles to enhance joint stability after primary THA. We asked whether this modified posterior approach would have a lower dislocation rate than the conventional posterior approach, with and without a repair of external rotator muscles. We retrospectively divided 557 patients (670 hips) who had undergone primary THA into three groups based on how the external rotator muscles had been treated during surgery: (1) not repaired after sectioning, (2) repaired after sectioning, or (3) not sectioned and preserved. The minimum followup was 1 year. In the group with preserved external rotator muscles, we observed no dislocations; in comparison, the dislocation rates for the repaired rotator group and the no-repair group were 3.9% and 5.3%, respectively. This modified posterior approach, which preserves the short external rotator muscles, seemed effective in preventing early dislocation after primary THA.Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

    View details for DOI 10.1007/s11999-007-0056-8

    View details for Web of Science ID 000253164100007

    View details for PubMedID 18196409

  • Torsional strength estimates of femoral diaphyses with endosteal lytic lesions: Dual-energy x-ray Absorptiometry study JOURNAL OF ORTHOPAEDIC RESEARCH Robertson, D. D., Beck, T. J., Chan, B. W., Scott, W. W., Sharma, G. B., Maloney, W. J. 2007; 25 (10): 1343-1350

    Abstract

    Pathologic fracture is a significant problem for individuals with metastatic bone disease. Current guidelines for prophylactic internal fixation are neither reliable nor easily applied. The purpose of this study was to validate dual-energy X-ray absorptiometry (DXA) as an accurate method for estimating torsional bone strength of diaphyseal bone with endosteal lytic lesions. Endosteal lesions of varying sizes were simulated in the diaphyses of 12 adult cadaveric femurs. Unaltered contralateral femurs served as matched controls. Machined lesions ranged from 3 to 6.5 cm in length, 1 to 3 cm in width, 15 to 48 cm(2) in elliptical area, with 10% to 100% removal of the cortical thickness. Morphology and density data obtained from DXA images were used to estimate torsional strength. All femora were mechanically tested to failure in torsion. Physically measured torsional strength was not significantly correlated to lesion elliptical area (r = 0.542, p > 0.05) or percentage cortical thickness removed (r = 0.257, p > 0.05). Measured torsional strength was significantly correlated to DXA-based torsional strength estimates (r = 0.855, p < 0.01). Lesion size alone did not correlate with the strength of bones with simulated endosteal lytic lesions. In contrast, calculations based on DXA (morphology, density) did correlate with torsional strength. This is the first step in the development of a DXA-based tool for objectively estimating bone strength in the presence of endosteal lytic lesions.

    View details for DOI 10.1002/jor.20419

    View details for Web of Science ID 000249671000010

    View details for PubMedID 17549708

  • The 2007 ABJS Marshall Urist Award - The impact of direct-to-consumer advertising in orthopaedics CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Bozic, K. J., Smith, A. R., Hariri, S., Adeoye, S., Gourville, J., Maloney, W. J., Parsley, B., Rubash, H. E. 2007: 202-219

    Abstract

    Direct-to-consumer advertising (DTCA) has become an influential factor in healthcare delivery in the United States. We evaluated the influence of DTCA on surgeon and patient opinions and behavior in orthopaedics by surveying orthopaedic surgeons who perform hip and knee arthroplasties and patients who were scheduled to have hip or knee arthro-plasty. Respondents were asked for their opinions of and experiences with DTCA, including the influence of DTCA on surgeon and patient decision making. Greater than 98% of surgeon respondents had experience with patients who were exposed to DTCA. The majority of surgeon respondents reported DTCA had an overall negative impact on their practice and their interaction with patients (74%), and their patients often were confused or misinformed about the appropriate treatment for their condition based on an advertisement (77%). Fifty-two percent of patient respondents recalled seeing or hearing advertisements related to hip or knee arthroplasty. These patients were more likely to request a specific type of surgery or brand of implant from their surgeon and to see more than one surgeon before deciding to have surgery. Direct-to-consumer advertising seems to play a substantial role in surgeon and patient decision making in orthopaedics. Future efforts should be aimed at improving the quality and accuracy of information contained in consumer-directed advertisements related to orthopaedic implants and procedures.

    View details for DOI 10.1097/BLO.0b013e31804fdd02

    View details for Web of Science ID 000246259200038

    View details for PubMedID 17353799

  • Clinical presentation of patients with tears of the acetabular labrum. journal of bone and joint surgery. American volume Burnett, R. S., Della Rocca, G. J., Prather, H., Curry, M., Maloney, W. J., Clohisy, J. C. 2006; 88 (7): 1448-1457

    Abstract

    The clinical presentation of a labral tear of the acetabulum may be variable, and the diagnosis is often delayed. We sought to define the clinical characteristics associated with symptomatic acetabular labral tears by reviewing a group of patients who had an arthroscopically confirmed diagnosis.We retrospectively reviewed the records for sixty-six consecutive patients (sixty-six hips) who had a documented labral tear that had been confirmed with hip arthroscopy. We had prospectively recorded demographic factors, symptoms, physical examination findings, previous treatments, functional limitations, the manner of onset, the duration of symptoms until the diagnosis of the labral tear, other diagnoses offered by health-care providers, and other surgical procedures that these patients had undergone. Radiographic abnormalities and magnetic resonance arthrography findings were also recorded.The study group included forty-seven female patients (71%) and nineteen male patients (29%) with a mean age of thirty-eight years. The initial presentation was insidious in forty patients, was associated with a low-energy acute injury in twenty, and was associated with major trauma in six. Moderate to severe pain was reported by fifty-seven patients (86%), with groin pain predominating (sixty-one patients; 92%). Sixty patients (91%) had activity-related pain (p < 0.0001), and forty-seven patients (71%) had night pain (p = 0.0006). On examination, twenty-six patients (39%) had a limp, twenty-five (38%) had a positive Trendelenburg sign, and sixty-three (95%) had a positive impingement sign. The mean time from the onset of symptoms to the diagnosis of a labral tear was twenty-one months. A mean of 3.3 health-care providers had been seen by the patients prior to the definitive diagnosis. Surgery on another anatomic site had been recommended for eleven patients (17%), and four had undergone an unsuccessful operative procedure prior to the diagnosis of the labral tear. At an average of 16.4 months after hip arthroscopy, fifty-nine patients (89%) reported clinical improvement in comparison with the preoperative status.The clinical presentation of a patient who has a labral tear may vary, and the correct diagnosis may not be considered initially. In young, active patients with a predominant complaint of groin pain with or without a history of trauma, the diagnosis of a labral tear should be suspected and investigated as radiographs and the history may be nonspecific for this diagnosis.Diagnostic Level IV. See Instructions to Authors for a complete description of levels of evidence.

    View details for PubMedID 16818969

  • Efficacy of combined modality prophylaxis including short-duration warfarin to prevent venous thromboembolism after total hip arthroplasty JOURNAL OF ARTHROPLASTY Keeney, J. A., Clohisy, J. C., Curry, M. C., Maloney, W. J. 2006; 21 (4): 469-475

    Abstract

    This study reviewed the effectiveness of a trimodality deep venous thrombosis (DVT) prophylactic regimen after primary and revision total hip arthroplasty. Seven hundred five patients were treated with pneumatic compression, adjusted dose warfarin (7 days), and early mobilization. Bilateral lower extremity venous ultrasonography was obtained on postoperative day 3 or 4. The incidence of asymptomatic DVT, symptomatic DVT/pulmonary embolus events within 90 days of surgery, and potential influence of risk factors was retrospectively assessed. Deep venous thrombosis incidence was 4.4% with one (0.1%) nonfatal pulmonary embolus. Increased age, male sex, and DVT history were significant risk factors for thromboembolic events within 90 days of hip arthroplasty. The combination of short-duration warfarin and mechanical prophylaxis with predischarge ultrasound screening was safe and effective in limiting the occurrence of venous thromboembolism.

    View details for DOI 10.1016/j.arth.2005.06.017

    View details for Web of Science ID 000238705200001

    View details for PubMedID 16781396

  • Management of acetabular bone loss. Instructional course lectures Maloney, W. J., Wadey, V. M. 2006; 55: 279-285

    Abstract

    Acetabular bone loss is a common complication associated with revision total joint replacement. Successful surgical management is enhanced by a systematic classification of bony defects. A variety of implants, fixation strategies, surgical techniques, and graft materials are required to address the spectrum of reconstructive complications encountered at revision surgery.

    View details for PubMedID 16958463

  • Removal of well-fixed cementless components. Instructional course lectures Maloney, W. J., Wadey, V. M. 2006; 55: 257-261

    Abstract

    Removal of stable, osseointegrated cementless components can be a challenge for the orthopaedic surgeon. Careful preoperative planning to assess the location and extent of the bone ingrowth or ongrowth as well as ensuring that the appropriate instrumentation is available in the operating room can help minimize complications when performing these procedures.

    View details for PubMedID 16958461

  • Acetabular and femoral radiographic abnormalities associated with labral tears CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Peelle, M. W., Della Rocca, G. J., Maloney, W. J., Curry, M. C., Clohisy, J. C. 2005: 327-333

    Abstract

    The purpose of our study was to define the incidence of acetabular and femoral osseous abnormalities associated with symptomatic acetabular labral tears. We reviewed the radiographs of 78 patients treated arthroscopically for labral tears and 22 patients with asymptomatic hips for comparison. Overall, 49% of patients with labral tears had at least one radiographic abnormality (17% acetabular, 14% femoral, and 18% both). Hip dysplasia was more prevalent in patients with labral tears (36%) compared with control subjects (0%). A decreased head-neck offset was present in 18% of patients with labral tears versus 5% of the control subjects. An anterolateral prominence at the femoral head-neck junction, creating an aspherical femoral head, was present in 29% of patients with labral tears. Sixty-one percent of those patients also met criteria for dysplasia and/or decreased head-neck offset. A retroverted acetabulum was present in 12% of patients with labral tears and none of the control subjects. Osteoarthritis was more common in patients with labral tears (33%) than in control subjects (9%). Because acetabular and femoral osseous abnormalities commonly are associated with labral tears, recognition of these abnormalities is important to optimize surgical treatment of patients with symptomatic labral disease. Level of Evidence: Diagnostic study, Level II (development of diagnostic criteria on consecutive patients-with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

    View details for DOI 10.1097/01.blo.0000181147.86058.74

    View details for Web of Science ID 000233794700049

    View details for PubMedID 16331022

  • Revision total knee arthroplasty for restricted motion CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Keeney, J. A., Clohisy, J. C., Curry, M., Maloney, W. J. 2005: 135-140

    Abstract

    Persistent stiffness is an infrequent but notable complication occurring after total knee arthroplasty. A limited approach (soft tissue releases and component retention with tibial insert downsizing) has previously been associated with poor results, although comprehensive revision of both components seems more successful. We retrospectively reviewed 23 patients (25 knees) who had revision total knee arthroplasty for painful limitation of motion. At a mean of 36.7 months after surgery we assessed pain, motion arc, and Knee Society clinical and functional scores. The effectiveness of a limited approach for selected patients (n = 12) was compared with more comprehensive revision of both components (n = 11). Patients with the limited approach had improvements in mean knee motion arc (25.7 degrees), mean clinical score (37.8 points), and mean functional score (20.8 points). Patients with component revision had a mean improvement in knee motion arc (17.9 degrees) but little change in the clinical score (3.6 points) or functional score (-1.0 points). The severity of preoperative flexion contractures and limited motion in patients having component revision likely contributed to the limited improvement. The data suggest a limited soft tissue approach may be appropriate for a select group of patients. The success of component revision for patients with severely restricted motion and more extensive flexion contracture was less predictable than authors of previous reports suggest.Therapeutic study, Level III-1 (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

    View details for DOI 10.1079/01.blo.0000185312.43955.c8

    View details for Web of Science ID 000233231000025

    View details for PubMedID 16239797

  • The surgical management of femoral osteolysis JOURNAL OF ARTHROPLASTY Maloney, W. J. 2005; 20 (4): 75-78

    Abstract

    Fifteen patients underwent reoperation for failed total hip arthroplasty. At surgery, patients who had proximal femoral osteolysis with osseointegrated femoral components were managed with lesional treatment that included debridement and bone grafting. The femoral components included 7 extensively coated stems, 5 proximally coated stems, and 3 modular femoral components. At a minimum 5-year follow-up evaluation, all 15 femoral components remained radiographically stable. Graft material in contained defects appeared to consolidate radiographically. For selected patients, debridement and grafting of femoral osteolytic defects provide satisfactory intermediate term outcomes.

    View details for DOI 10.1016/j.arth.2005.03.019

    View details for Web of Science ID 000230134300022

    View details for PubMedID 15991137

  • Magnetic resonance arthrography versus arthroscopy in the evaluation of articular hip pathology CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Keeney, J. A., Peelle, M. W., Jackson, J., Rubin, D., Maloney, W. J., Clohisy, J. C. 2004: 163-169

    Abstract

    In this study, we compared magnetic resonance arthrography results with hip arthroscopy findings to assess the diagnostic value of this imaging technique in evaluating acetabular labral tears and concurrent articular hip pathology. One hundred one consecutive patients (102 hips) with a clinical diagnosis of acetabular labral tear were assessed using magnetic resonance arthrography and had hip arthroscopy after failing to improve with nonoperative treatment. Magnetic resonance arthrography detected 71 of 93 (76%) acetabular labral tears (92 patients) with five false positive studies in five patients (4.9%). Articular cartilage findings diagnosed by magnetic resonance arthrography were confirmed by arthroscopy in 64 hips in 64 patients (62.7%). With respect to labral pathology, magnetic resonance arthrography showed a sensitivity of 71%, specificity of 44% positive predictive value of 93%, negative predictive value of 13%, and accuracy of 69%. With respect to articular cartilage pathology, magnetic resonance arthrography had a sensitivity of 47%, specificity of 89%, positive predictive value of 84%, negative predictive value of 59%, and accuracy of 67%. Although magnetic resonance arthrography is an excellent positive predictor in diagnosing acetabular labral tears and articular cartilage abnormalities, it has limited sensitivity. A negative imaging study does not exclude important intra-articular pathology that can be identified and treated arthroscopically.

    View details for DOI 10.1097/01.blo.0000150125.34906.7d

    View details for Web of Science ID 000225549900025

    View details for PubMedID 15577482

  • Biomechanics of large femoral heads - What they do and don't do CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Crowninshield, R. D., Maloney, W. J., Wentz, D. H., Humphrey, S. M., Blanchard, C. R. 2004: 102-107

    Abstract

    The stability and durability of total hip reconstruction is dependent on many factors that include the design and anatomic orientation of prosthetic components. An analysis of femoral component head size and acetabular component orientation shows an interdependency of these variables and joint stability. Increased femoral component head size can increase hip stability by increasing the prosthetic impingement-free range of hip motion and by increasing the inferior head displacement required before hip dislocation. Increasing the femoral head size from 22 mm to 40 mm increases the required displacement for dislocation by about 5 mm with the acetabular component at 45 degrees of abduction; however, increasing acetabular component abduction greatly diminishes this stability advantage of larger femoral heads. Vertical acetabular component orientation and femoral component head subluxation are each predicted to more than double the tensile stress with acetabular component polyethylene compared with components at 45 degrees of abduction. With a desirable acetabular component orientation, the use of larger femoral heads may result in improved joint stability and durable use of polyethylene. With high abduction acetabular component orientation, the use of larger femoral heads contributes little to joint stability and contributes to elevated stress within the polyethylene that may result in implant failure.

    View details for DOI 10.1097/01.blo.0000150117.42360.f9

    View details for Web of Science ID 000225549900016

    View details for PubMedID 15577473

  • Reasons for revision hip surgery - A retrospective review CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Clohisy, J. C., Calvert, G., Tull, F., McDonald, D., Maloney, W. J. 2004: 188-192

    Abstract

    The purpose of this study was to determine the indications for contemporary revision hip surgery in a consecutive series of patients. We retrospectively reviewed the clinical records and radiographs of 439 revision hip surgeries done between 1996 and 2003. Fifty-five percent of the surgeries were for aseptic loosening, 14% were for instability, 13% were for osteolysis around a well-fixed implant, 7% were for infection, 5% were for periprosthetic fracture, 3% were for conversion of a hemiarthroplasty, 1% was for psoas impingement, 1% was for loose recalled implants, and 1% was for implant fracture. As expected, aseptic loosening was the most common reason for revision surgery. Instability was a common reason for early revision whereas revision for osteolysis around a well-fixed implant was a more common reason for late revision.

    View details for DOI 10.1097/01.blo.0000150126.73024.42

    View details for Web of Science ID 000225549900029

    View details for PubMedID 15577486

  • Leg length discrepancy after total hip arthroplasty JOURNAL OF ARTHROPLASTY Maloney, W. J., Keeney, J. A. 2004; 19 (4): 108-110

    Abstract

    Restoration of hip biomechanics, including femoral offset and leg length are desired goals in performing total hip arthroplasty. Minor leg length discrepancies, less than a centimeter, are common after total hip arthroplasty and usually well tolerated. However in some patients, even these small discrepancies are a source of dissatisfaction. In addition, more significant discrepancies can be a risk factor for nerve injury and are a relatively common cause of litigation. Although leg length discrepancy cannot be eliminated after hip arthroplasty, it can be minimized through a series of steps both preoperatively and intraoperatively. These include physical examination to determine true and apparent leg length, and radiographic evaluation to both assess leg length and to preoperatively template the surgical procedure. Finally, the preoperative plan needs to be executed in the operating room using appropriate intraoperative cues.

    View details for DOI 10.1016/j.arth.2004.02.018

    View details for Web of Science ID 000222353400025

    View details for PubMedID 15190563

  • The role of proximal femoral support in stress development within hip prostheses CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Crowninshield, R. D., Maloney, W. J., Wentz, D. H., Levine, D. L. 2004: 176-180

    Abstract

    Bone remodeling commonly associated with implant loosening may require revision total hip replacement when there is substantial proximal femoral bone loss. Additionally, the surgical exposure required to remove primary implants may alter the proximal femur's structure. As a result, in many revision hip situations the proximal femur provides compromised support for the revision femoral component. Stress analyses of the proximal femur with extensively porous-coated prosthetic femoral components show that proximomedial femoral bone loss, ununited femoral osteotomy, and periprosthetic fracture can result in significant elevation of stress within revision prosthetic components. The first principal stress within prosthetic components can, in proximal bone loss conditions, be elevated significantly above a revision prostheses' fatigue strength. Loss of proximomedial bone is predicted to increase stress within a revision component by as much as 82%. An unhealed transverse femoral fracture or osteotomy is predicted to more than double the stress within a revision femoral component. In revision total hip replacement, efforts directed toward the restoration of proximal femoral bone and the use of larger prostheses may contribute to avoiding prostheses fatigue fracture. Similarly, protected weightbearing in patients with ununited femoral osteotomies and periprosthetic fractures may be important to preventing prosthetic fracture.

    View details for Web of Science ID 000220580200024

    View details for PubMedID 15057094

  • An AOA critical issue. The outcome of the outcomes movement. journal of bone and joint surgery. American volume Bourne, R. B., Maloney, W. J., Wright, J. G. 2004; 86-A (3): 633-640

    View details for PubMedID 14996894

  • Adenovirus mediated BMP-13 gene transfer induces chondrogenic differentiation of murine mesenchymal progenitor cells JOURNAL OF BONE AND MINERAL RESEARCH Nochi, H., Sung, J. H., Lou, J., Adkisson, H. D., Maloney, W. J., Hruska, K. A. 2004; 19 (1): 111-122

    Abstract

    Chondrogenic/osteogenic differentiation of a mesenchymal progenitor stimulated by BMP-13 (CDMP-2) was studied. C3H10T1/2 cells were transduced by an adenoviral construct containing BMP-13 or BMP-2. BMP-13 supported chondrogenesis but not terminal differentiation, whereas BMP-2 stimulated endochondral ossification. The studies show that BMP-13 may fail to support terminal chondrocyte differentiation.Bone morphogenetic protein (BMP)-13 is a member of the transforming growth factor beta (TGF-beta) superfamily of growth factors. Although the biological functions of BMP-13 remain poorly understood, continued postnatal expression of BMP-13 in articular cartilage suggests that this protein may function in an autocrine/paracrine fashion to regulate growth and maintenance of articular cartilage. The purpose of this study was to elucidate the role of BMP-13 in chondrogenic differentiation.Replication-deficient adenoviruses carrying human BMP-13 (Adv-hBMP13), bacterial beta-galactosidase (Adv-beta gal), and human BMP-2 (Adv-hBMP2) were constructed. Murine mesenchymal progenitor cells (C3H10T1/2) were transduced with these vectors, and differentiation to the chondrogenic lineage was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR), biochemical, and histological analyses.Our findings revealed that hBMP-13 transduced cells differentiated into round cells that stained with Alcian blue. Analysis of gene expression in hBMP-13-transduced cells demonstrated presence of cartilage-specific markers, absence of hypertrophic chondrocyte specific markers, and upregulation of proteoglycan biosynthesis. In particular, hBMP-13-transduced cells had significantly less and delayed expression of alkaline phosphatase activity and calcium mineral accumulation than hBMP-2-transduced cells. Except for BMPR-IB/ALK-6, expression of BMP receptors was identified constitutively in C3H10T1/2 cells and was not affected by the presence of either of the BMPs. In summary, hBMP-13, while stimulating chondrogenesis, failed to support differentiation to hypertrophic chondrocytes and endochondral ossification similar to hBMP-2. Thus, this may prove to be a useful strategy for cell-based regeneration of articular cartilage.

    View details for Web of Science ID 000187567800014

    View details for PubMedID 14753743

  • Fluoroscopic analyses of cruciate-retaining and medial pivot knee implants CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Schmidt, R., Komistek, R. D., Blaha, J. D., Penenberg, B. L., Maloney, W. J. 2003: 139-147

    Abstract

    Contemporary posterior cruciate-retaining total knee designs have provided pain relief and improved knee function but have failed to reproduce the kinematics and stability of the normal nonarthritic knee. The Medial Pivot total knee design features a near constant radius of curvature of the femoral component. The tibial surface is highly congruent and asymmetric, permitting a medial pivot motion during knee flexion. The purpose of the current study was to analyze and compare the gait kinematics of the Sigma posterior cruciate-retaining total knee implant, the Advance Traditional posterior cruciate-retaining total knee implant, and the Advance Medial Pivot knee implant using fluoroscopic analysis. In vivo kinematics were determined for 15 clinically successful total knee arthroplasties. Five knee implants were evaluated from each group. The authors analyzed the kinematics of knee motion during the stance phase of gait for each patient. On average, subjects with the Medial Pivot knee implant had a medial pivot motion. Both posterior cruciateretaining designs had a paradoxical roll forward of the tibia on femur during knee flexion and had greater excursion of both condyles during knee flexion than the medial pivot design. Nine of 10 of the posterior cruciate-retaining designs had condylar lift-off averaging 1.7 mm whereas only one Medial Pivot knee implant had condylar lift-off measuring 1.1 mm.

    View details for DOI 10.1097/01.blo.0000063565.90853.a4

    View details for Web of Science ID 000182630400015

    View details for PubMedID 12771824

  • Human serum opsonization of orthopedic biomaterial particles: Protein-binding and monocyte/macrophage activation in vitro JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A Sun, D. H., Trindade, M. C., Nakashima, Y., Maloney, W. J., Goodman, S. B., Schurman, D. J., Smith, R. L. 2003; 65A (2): 290-298

    Abstract

    Wear particles generated after total joint arthroplasty activate monocyte/macrophages and incite formation of a granulomatous periprosthetic tissue associated with bone loss and implant loosening. This study tested the hypothesis that selective opsonization of orthopedic implant biomaterial wear particles by human serum proteins influences monocyte/macrophage activation. Serum protein binding to metallic, polymeric, and ceramic particles was determined by one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Individual proteins bound to particles were subsequently identified using two-dimensional SDS-PAGE, microsequencing techniques, and SWISS-PROT analysis. Effects of selective protein opsonization on particle-induced monocyte/macrophage activation were assessed by quantification of interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha release. Results from one-dimensional gel analyses revealed distinct serum protein-binding patterns specific for each material tested. Two-dimensional gel analysis together with amino acid sequencing of the prominent protein species confirmed the presence of albumin and alpha-1-antitrypsin bound to all particles tested. In contrast to the metallic particles, apolipoprotein was a major species associated with polymeric particles. Opsonization of PMMA particles with purified preparations of each of the identified proteins showed that albumin significantly enhanced particle-induced monocyte/macrophage activation. These data confirm orthopedic biomaterial specific binding of human serum proteins and demonstrate that albumin exacerbates particle-induced monocyte/macrophage activation. Alterations in the chemical and surface properties of orthopedic biomaterials to modulate protein interactions may improve implant longevity.

    View details for DOI 10.1002/jbm.a.10477

    View details for Web of Science ID 000182627600022

    View details for PubMedID 12734824

  • Cementless and cemented implants had similar survival in total knee replacement. journal of bone and joint surgery. American volume Maloney, W. J. 2003; 85-A (5): 973-?

    View details for PubMedID 12728060

  • Femoral component design and patellar clunk syndrome CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Schmidt, R., Sculco, T. P. 2003: 199-202

    Abstract

    The effect of patellar design of the femoral component on the prevalence of patellar clunk was examined by comparing 179 consecutive Insall-Burstein II posterior-stabilized total knee replacements with 210 consecutive primary Advanced posterior-stabilized total knee replacements. In the Advanced posterior-stabilized knee replacements, the patellofemoral groove had been extended posteriorly 7.5 mm compared with the Insall-Burstein II implant. At a minimum followup of 2 years, the prevalence of patellar clunk syndrome in the patients with a Insall-Burstein II knee replacement was 3.9% (seven of 179) compared with 0% in the patients with an Advanced posterior-stabilized knee replacement. Based on these data, it seems that the design change in patellofemoral groove of the Advanced posterior-stabilized knee replacement has eliminated the problem of patellar clunks.

    View details for DOI 10.1097/01.blo.0000063606.67412.96

    View details for Web of Science ID 000182630400022

    View details for PubMedID 12771831

  • Knee kinematics and total knee replacement design. Clinical orthopaedics and related research Maloney, W. J., Clohisy, J. C. 2003: 3-4

    View details for PubMedID 12771810

  • Orthopaedic crossfire--Larger femoral heads: a triumph of hope over reason! In opposition. journal of arthroplasty Maloney, W. J. 2003; 18 (3): 85-87

    Abstract

    For the past decade, large femoral heads have for the most part been avoided in total hip arthroplasty, especially in younger active patients, because of their association with increased polyethylene wear. However, it has become equally clear that large femoral heads offer a benefit in terms of hip stability and reducing postoperative dislocation. With increasing head size, there is less chance of component-on-component impingement and increased displacement for dislocation. Highly cross-linked polyethylene appears to be relatively insensitive to head size and may offer the surgeon the opportunity to use large femoral heads, especially in patients who are at high risk for dislocation.

    View details for PubMedID 12730936

  • Hip biomechanics: importance to functional imaging. Seminars in musculoskeletal radiology Robertson, D. D., Britton, C. A., Latona, C. R., Armfield, D. R., Walker, P. S., Maloney, W. J. 2003; 7 (1): 27-41

    Abstract

    Although well recognized the hip joint is not well understood. In many respects knowledge of the hip is similar to that of the knee several decades ago. Increased understanding of the hip's structure and function will improve our ability to diagnose and treat pre-end-stage hip joint disease. This article describes relevant anatomy and mechanics and details the crucial role that imaging plays in current assessments of hip function.

    View details for PubMedID 12888942

  • Stimulation of BMP-2 expression by pro-inflammatory cytokines IL-1 and TNF-alpha in normal and osteoarthritic chondrocytes. journal of bone and joint surgery. American volume Fukui, N., Zhu, Y., Maloney, W. J., Clohisy, J., Sandell, L. J. 2003; 85-A: 59-66

    Abstract

    Destruction of cartilage in osteoarthritis is a direct effect of an imbalance between catabolic and anabolic activities in the tissue. While a great deal is known about catabolism, we sought to determine the biochemical basis of the anabolic activity.Cartilage was isolated from normal and osteoarthritic patients and subjected to both cell and explant culture. mRNA expression levels of the growth and differentiation factors bone morphogenetic protein-2 (BMP-2), BMP-4, BMP-6, cartilage-derived morphogenetic protein-1 (CDMP-1), connective tissue growth factor (CTGF), and activin were determined. BMP-2 was localized in osteoarthritic cartilage by immunohistochemistry. To determine the mechanism of BMP-2 stimulation, chondrocytes were cultured with TGF-beta (transforming growth factor-beta), insulin-like growth factor-1 (IGF-1), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The BMP-2 response was monitored by quantitative real-time polymerase chain reaction to ascertain mRNA levels and by Western blot analysis, BMP-2 protein quantitation, and immunohistochemistry to determine protein levels.BMP-2 was found to be up-regulated in osteoarthritic chondrocytes and cartilage. In cell culture, IL-1beta and TNF-alpha increased BMP-2 mRNA and protein levels by eightfold and fifteenfold, respectively, whereas IGF-1 and TGF-beta1 had no effect. In cartilage explant cultures, IL-1beta and TNF-alpha increased BMP-2 levels both intracellularly and extracellularly. Functional relevance was suggested by co-localization of BMP-2 and newly synthesized type-II procollagen within the same cells.BMP-2 acts as a stimulus of anabolic activities in normal and osteoarthritic chondrocytes. Furthermore, the pro-inflammatory cytokines IL-1beta and TNF-alpha, known to be present in synovium and cartilage of patients with osteoarthritis, stimulate the production of active BMP-2.

    View details for PubMedID 12925611

  • Analysis of long-term cemented total hip arthroplasty retrievals CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Schmalzried, T., Harris, W. H. 2002: 70-78

    Abstract

    A detailed biomechanical, histologic, and histomorphometric analysis of autopsy specimens from patients who previously had cemented total hip arthroplasty has helped to elucidate the skeletal response to cemented components. Bone cement has the capacity to provide long-term implant stability. The biologic response to polyethylene wear debris has a more critical effect on destabilization of cemented sockets compared with the femoral side. In contrast, mechanical events tended to predominate the early mode of destabilization of cemented femoral components with debonding at the metal-cement interface and fracture in the cement. Fractures predominate in cement mantles less than 1 mm thick and are associated with mantle defects, debonded interfaces, and sharp corners of the implants. Correlation of the histologic findings at the cement-bone interface with radiolucencies seen on clinical radiographs show that on the acetabular side radiolucencies represent a soft tissue membrane that is the biologic response to polyethylene debris. In contrast, on the femoral side, most radiolucencies were as a result of skeletal remodeling. Femoral adaptive bone remodeling is a diffuse process that occurs over the entire fixation surface. The most profound disuse osteoporosis occurred proximally in the proximal medial quadrant; however, when one takes into account all four quadrants, anterior, posterior, medial, and lateral, the most severe osteoporosis occurred at the midpoint of the stem.

    View details for DOI 10.1097/01.blo.0000038060.29678.90

    View details for Web of Science ID 000179861400009

    View details for PubMedID 12461358

  • Enhanced cross-linked polymers: The promise - In the affirmative ORTHOPEDICS Maloney, W. J. 2002; 25 (9): 936-937

    View details for Web of Science ID 000178008700013

    View details for PubMedID 12269417

  • An American implant registry: A clinical use trip wire ORTHOPEDICS Maloney, W. J. 2002; 25 (9): 923-924

    View details for Web of Science ID 000178008700007

    View details for PubMedID 12269411

  • Case challenges in knee surgery - What would you do? JOURNAL OF ARTHROPLASTY Hanssen, A. D., Dorr, L. D., Kurosaka, M., Maloney, W. J., Romagnoli, S., Ranawat, C. S. 2002; 17 (4): 83-89

    Abstract

    In an interactive case presentation session, the faculty discussed management of complex primary and revision knee arthroplasty issues. Principles discussed included: preoperative evaluation of the failed knee arthroplasty, intra-articular versus extra-articular deformity correction, ligamentous balancing, managing the unstable total knee arthroplasty, bone deficiency management, rotational positioning of prosthetic components, selection of articular constraint in the revision knee, and extensor mechanism balancing.

    View details for DOI 10.1054/arth.2002.32546

    View details for Web of Science ID 000176377400024

    View details for PubMedID 12068413

  • Common threads in hip, knee, and shoulder arthroplasty JOURNAL OF ARTHROPLASTY Maloney, W. J. 2002; 17 (4): 2-2

    View details for DOI 10.1054/arth.2002.32544

    View details for Web of Science ID 000176377400002

    View details for PubMedID 12068391

  • The stiff total knee arthroplasty - Evaluation and management JOURNAL OF ARTHROPLASTY Maloney, W. J. 2002; 17 (4): 71-73

    Abstract

    Arthrofibrosis after total knee arthroplasty is a relatively common complication. A variety of modalities have been employed to treat this problem, including physical therapy, injections, and manipulations. We examined a group of consecutive posterior stabilized total knee arthroplasties to determine the prevalence of arthrofibrosis, as defined by flexion <90 degrees, and the effect of manipulation under anesthesia on outcome. Approximately 11% of the patients met the criteria for arthrofibrosis. Manipulation under anesthesia was successful in improving flexion from an average of 67 degrees premanipulation to 111 degrees postmanipulation. The group that required manipulation did as well statistically as the group as a whole, which had a mean flexion of 114 degrees at 1 year.

    View details for DOI 10.1054/arth.2002.32450

    View details for Web of Science ID 000176377400021

    View details for PubMedID 12068410

  • Biochemical analyses of human macrophages activated by polyethylene particles retrieved from interface membranes after failed total hip arthroplasty JOURNAL OF ARTHROPLASTY Chiba, J., Maloney, W. J., Inoue, K., Rubash, H. E. 2001; 16 (8): 101-105

    Abstract

    Human monocyte/macrophages (M/M) were exposed to retrieved ultra-high molecular weight polyethylene (UHMWPE) particles isolated after enzymatic digestion of revision total hip arthroplasty interface membrane tissue samples. The cellular response of human M/M to UHMWPE was compared with the response of these cells to latex particles and culture medium alone. We incubated macrophages in good contact with polyethylene particles using an inverted culture system. Chamber slides on which macrophages were attached were filled with polyethylene particle suspension and sealed with plastic sheets. After the slides were inverted, the incubation was completed. Retrieved UHMWPE particulate debris stimulated human M/M to secrete interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha. Human M/M exposed to retrieved UHMWPE particles secreted significantly more IL-1beta, IL-6, and TNF-alpha compared with M/M exposed to latex particles (P<.05).

    View details for Web of Science ID 000172831900018

    View details for PubMedID 11742459

  • National Joint Replacement Registries: has the time come? journal of bone and joint surgery. American volume Maloney, W. J. 2001; 83-A (10): 1582-1585

    View details for PubMedID 11679613

  • Knee challenges: What would you do? ORTHOPEDICS Maloney, W. J., Dorr, L. D., Cuckler, J. M., Whiteside, L. A., Cameron, H. U., Buechel, F. F. 2001; 24 (9): 911-913

    View details for Web of Science ID 000171117000034

    View details for PubMedID 11570483

  • Hip challenges: What would you do? ORTHOPEDICS Dorr, L. D., Maloney, W. J., Gie, G., Goldberg, V. M., Engh, C. A., Mallory, T. H. 2001; 24 (9): 907-909

    View details for Web of Science ID 000171117000033

    View details for PubMedID 11570482

  • G-protein activity requirement for polymethylmethacrylate and titanium particle-induced fibroblast interleukin-6 and monocyte chemoattractant protein-1 release in vitro JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Trindade, M. C., Schurman, D. J., Maloney, W. J., Goodman, S. B., Smith, R. L. 2000; 51 (3): 360-368

    Abstract

    Periprosthetic granulomatous membranes consisting of fibroblasts, macrophages, lymphocytes, foreign body giant cells, and abundant particulate debris occur at sites of implant loosening. Previous studies demonstrate that fibroblasts respond to particulate debris through the release of interleukin-6 (IL-6), prostaglandin E(2), and matrix metalloproteinases in vitro. C-C chemokines are observed in granulomatous tissue surrounding loosened prosthetic implants and are released by macrophages and fibroblasts in response to particle challenge in vitro. This study tested the hypothesis that G protein activity is required for fibroblast activation by titanium and polymethylmethacrylate (PMMA) particles, and that inhibition of G protein activity would alter IL-6 and and monocyte chemoattractant protein-1 (MCP-1) release from activated fibroblasts. The specific inhibitor of G protein activity, pertussis toxin, was added to the fibroblasts to examine the effects of G protein activity with respect to the production of IL-6 and MCP-1 by orthopedic biomaterial-challenged fibroblasts in vitro. Interleukin-1beta (IL-1beta), a proven activator of MCP-1 and interleukin-6, was used as a positive control. Exposure of fibroblasts to titanium and polymethylmethacrylate (PMMA) particles resulted in a dose-dependent release of MCP-1 and IL-6. Challenge with PMMA particles at doses of 0.150%, 0.300%, and 0.600% vol/vol increased the release of interleukin-6 by 7-, 19-, and 22-fold, respectively, compared to fibroblasts exposed to serum-free culture medium alone at 24 h. Challenge with PMMA particles at doses of 0.075%, 0.150%, 0.300%, and 0.600% vol/vol increased the release of MCP-1-6 by 2.5-, 3.6-, 4. 3-, and 4.5-fold, respectively, compared to fibroblasts exposed to serum-free culture medium alone. Challenge with titanium particles at concentrations of 0.075%, 0.150%, 0.300%, and 0.600% vol/vol increased the release of interleukin-6 by 2.6-, 6.4-, 9.6-, and 10. 0-fold, respectively, compared to fibroblasts exposed to serum-free culture medium alone at 24 h. Challenge with titanium particles at concentrations of 0.038%, 0.075%, 0.150%, 0.300%, and 0.600% vol/vol increased the release of MCP-1 by 2.9-, 3.1-, 5.8-, 5.4-, and 5. 8-fold, respectively, compared to fibroblasts exposed to serum-free culture medium alone. Pretreatment of fibroblasts with pertussis toxin inhibited the release of interleukin-6 and MCP-1 from PMMA and titanium particle challenged fibroblasts in a dose-dependent manner. PMMA particle induced fibroblast IL-6 release was inhibited by 23.6% and 35.3% with 20- and 200-ng/mL doses of pertussis toxin, respectively. Titanium particle induced fibroblast IL-6 release was inhibited by 48.2% and 56.3% with 20- and 200-ng/mL doses of pertussis toxin, respectively. PMMA particle-induced fibroblast MCP-1 release was inhibited by 36.0%, 50.4%, and 60.1% with 2-, 20- and 200-ng/mL doses of pertussis toxin, respectively. Titanium particle-induced fibroblast MCP-1 release was inhibited by 15.5%, 53.2%, and 64.6% with 2-, 20-, and 200-ng/mL doses of pertussis toxin, respectively. This study suggests that fibroblasts localized in periprosthetic membranes are a source of macrophage chemoattractant factors and proinflammatory mediators that may influence granuloma formation and lead to periprosthetic bone resorption. Furthermore, this study shows that G proteins are involved in particle-induced fibroblast activation, as evidenced by decrease levels of particle induced IL-6 and MCP-1 release following pertussis toxin treatment. (c) 2000 John Wiley & Sons, Inc.

    View details for Web of Science ID 000087914500009

    View details for PubMedID 10880077

  • Socket retention: Staying in place ORTHOPEDICS Maloney, W. J. 2000; 23 (9): 965-966

    View details for Web of Science ID 000089386300018

    View details for PubMedID 11003101

  • The bearing surface in total hip arthroplasty: evolution or revolution. Instructional course lectures Sharkey, P. F., Hozack, W. J., Dorr, L. D., Maloney, W. J., Berry, D. 2000; 49: 41-56

    Abstract

    Highly cross-linked polyethylenes represent a new class of polyethylenes that demonstrate dramatic improvements of wear characteristics in laboratory tests. Cross-linked polyethylenes can be manufactured by a number of methods, all of which lead to some changes in the physical properties of the polyethylene. The very limited clinical information about cross-linked polyethylenes available has been favorable. Cross-linked polyethylenes appear to hold promise as an alternative to conventional polyethylene and to hard-on-hard bearing surfaces, but much more clinical information will be required before they can be recommended for routine clinical use.

    View details for PubMedID 10829160

  • Interferon-gamma exacerbates polymethylmethacrylate particle-induced interleukin-6 release by human monocyte/macrophages in vitro JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Trindade, M. C., Lind, M., Goodman, S. B., Maloney, W. J., Schurman, D. J., Smith, R. L. 1999; 47 (1): 1-7

    Abstract

    Periprosthetic membranes commonly observed at sites of total joint implant loosening exhibit abundant macrophages and particulate debris. Macrophages phagocytose orthopedic debris and release the pro-inflammatory mediators interleukin-1, interleukin-6, tumor necrosis factor-alpha, and prostaglandin E2. In addition, other immunologic agents, such as interferon-gamma, are present in tissues harvested from the bone-implant interface of failed orthopedic implants. The present study examined the effects of interferon-gamma on polymethylmethacrylate (PMMA) particle-challenged monocyte/macrophages in vitro. The effects of interferon-gamma were determined by measuring interleukin-6 and tumor necrosis factor-alpha release by primary human monocyte/macrophages following exposure to PMMA particles. Exposure of the monocyte/macrophages to PMMA particles resulted in a dose-dependent release of interleukin-6 and tumor necrosis factor-alpha at 48 h. The interleukin-6 release in response to PMMA particle challenge was stimulated by 76% and 127% in the presence of 1.0 and 10.0 ng/mL of interferon-gamma, respectively. Interferon-gamma challenge alone did not alter interleukin-6 release relative to controls. In contrast to interleukin-6, interferon-gamma challenge stimulated tumor necrosis factor-alpha release in a dose-dependent manner. In the presence of particles, addition of 1.0 and 10.0 ng/mL of interferon-gamma resulted in 17% and 171% increases in the levels of tumor necrosis factor-alpha release, respectively, relative to cultures challenged solely with particles. Blocking antibody to IFN-gamma inhibited the effect of IFN-gamma on particle-induced interleukin-6 and tumor necrosis factor-alpha release. The data presented in this study demonstrate that the immunologic modulator interferon-gamma exacerbates monocyte/macrophage release of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha in response to PMMA particle challenge in vitro.

    View details for Web of Science ID 000081599800001

    View details for PubMedID 10400874

  • Reduced bone stress as predicted by composite beam theory correlates with cortical bone loss following cemented total hip arthroplasty JOURNAL OF ORTHOPAEDIC RESEARCH Silva, M. J., Reed, K. L., Robertson, D. D., Bragdon, C., Harris, W. H., Maloney, W. J. 1999; 17 (4): 525-531

    Abstract

    Clinical and experimental evidence suggest that periprosthetic bone loss following total hip arthroplasty is caused in part by stress-shielding. Changes in bone stress in the proximal femur following implantation can be estimated with use of composite beam theory. We hypothesized that the degree of stress-shielding predicted by beam theory correlates with the magnitude of bone loss following cemented total hip arthroplasty. We analyzed cross sections from the proximal femur of 13 patients who had undergone unilateral cemented total hip arthroplasty. A matching implant was inserted contralaterally, and the cross-sectional properties of the implant and bone and the bone density were determined. Bone loss was calculated on the basis of differences between contralateral (control) and ipsilateral (remodeled) sections and correlated to several beam-theory parameters calculated from the control sections: implant rigidity, bone rigidity, ratio of implant to bone rigidity, and predicted decrease in bone stress. All parameters except implant rigidity were significantly correlated with bone loss (p < 0.05). Parameters that included implant and bone properties were more strongly correlated with bone loss than were those based on bone properties alone. The predicted decrease in bone stress explained 50-60% of the variance in bone loss. The data also indicated that patients were not likely to lose substantial amounts of bone unless the reduction in bone stress exceeded a threshold value. Although limited by a small and heterogeneous sample, these results indicate that beam-theory predictions correlate with the degree of femoral resorption and should be investigated further as a means to identify patients at high risk for bone loss.

    View details for Web of Science ID 000082015400008

    View details for PubMedID 10459758

  • Reexpression of type IIA procollagen by adult articular chondrocytes in osteoarthritic cartilage ARTHRITIS AND RHEUMATISM Aigner, T., Zhu, Y., Chansky, H. H., MATSEN, F. A., Maloney, W. J., Sandell, L. J. 1999; 42 (7): 1443-1450

    Abstract

    To test for the reexpression of the chondroprogenitor splice variant of the gene COL2A1, type IIA procollagen (containing a cysteine-rich NH2 propeptide), in adult articular chondrocytes in osteoarthritic (OA) joint disease.In situ hybridization and immunohistochemical localization were performed on normal and OA articular cartilage specimens. The presence of type IIA procollagen messenger RNA (mRNA) expression was confirmed by Northern blot analysis.In normal articular cartilage, no expression of mRNA or presence of type IIA procollagen was found. In OA articular cartilage, focally intense staining for type IIA protein was detected. Consistent with this, chondrocytes, particularly in the middle zones of articular cartilage, expressed type IIA procollagen mRNA. OA repair cartilage typically showed a broad zone of cells expressing type IIA mRNA and protein.Type IIA procollagen is reexpressed by adult articular chondrocytes in OA cartilage degeneration, indicating the potential reversion of the cells to a chondroprogenitor cellular phenotype. The absence of type IIA mRNA and protein in normal adult articular cartilage and its onset in the diseased state suggests type IIA procollagen as a marker of OA.

    View details for Web of Science ID 000081259400018

    View details for PubMedID 10403272

  • Signaling pathways for tumor necrosis factor-alpha and interleukin-6 expression in human macrophages exposed to titanium-alloy particulate debris in vitro. journal of bone and joint surgery. American volume Nakashima, Y., Sun, D. H., Trindade, M. C., Maloney, W. J., Goodman, S. B., Schurman, D. J., Smith, R. L. 1999; 81 (5): 603-615

    Abstract

    Loosening of the implant after total joint arthroplasty remains a serious problem. The activation of macrophages by wear debris from implants, mediated by the release of cytokines that elicit bone resorption, may lead to loosening. The purpose of the present study was to elucidate the mechanisms of macrophage activation by titanium particles from the components of implants and to identify the signaling pathways involved in particle-mediated release of cytokines.Macrophages were isolated from mononuclear leukocytes obtained from healthy human donors and were exposed to titanium-alloy particles that had been obtained from periprosthetic membranes collected at revision total joint arthroplasties and then enzymatically prepared. The experimental protocols included examination of the effects of the inhibition of phagocytosis and the binding of antibodies to macrophage complement receptors on particle-induced macrophage activation. The release of the proinflammatory cytokines TNF-alpha (tumor necrosis factor-alpha) and IL-6 (interleukin-6) was used to assess macrophage activation. The signaling pathways involved in the induction of cytokine release were analyzed by identification of phosphorylated proteins with use of the Western blot technique and by translocation of the transcription factors nuclear factor-kappa B (NF-kappaB) and nuclear factor-interleukin-6 (NF-IL-6) into the nuclear protein fraction with use of electrophoretic mobility shift assays. The role of serine/threonine and tyrosine kinase pathways in the activation of nuclear factors and the release of cytokines was examined with use of selective pharmacological agents.Exposure of macrophages to titanium-alloy particles in vitro for forty-eight hours resulted in a fortyfold increase in the release of TNF-alpha and a sevenfold increase in the release of IL-6 (p<0.01). Phagocytosis of particles occurred in approximately 73 percent of the macrophages within one hour of exposure. Pretreatment of the macrophages with cytochalasin B reduced phagocytosis by 95 percent but did not reduce the release of TNF-alpha or IL-6. Thus, phagocytosis of particles was not necessary for induction of the release of TNF-alpha or IL-6 in the cultured macrophages. Ligation of the macrophage CD11b/CD18 receptors by integrin-specific antibodies also increased the release of TNF-alpha and IL-6. Antibodies to CD11b/ CD18 receptors (macrophage Mac-1 receptors) reduced phagocytosis of particles by 50 percent (p<0.05). (The CD11b/CD18 macrophage receptor is the macrophage receptor for the complement component CR3bi. The CD11b/CD18 macrophage receptor can also bind to ICAM-1 and ICAM-2. CD is the abbreviation for cluster of differentiation, and ICAM is the abbreviation for intercellular adhesion molecule.) Inhibition of phagocytosis was not accompanied by a decrease in the release of TNF-alpha and IL-6. Blocking RNA synthesis with actinomycin D or preventing protein synthesis with cycloheximide abolished or decreased particle-induced release of TNF-alpha and IL-6 from the macrophages. Macrophage release of TNF-alpha and IL-6 in response to particles coincided with increased tyrosine phosphorylation and mitogen-activated protein kinase activation. Inhibition of tyrosine and serine/threonine kinase activity decreased the particle-induced release of cytokines. Exposure of macrophages to either titanium-alloy particles or to antibodies to the receptor proteins CD11b and CD18 for thirty minutes activated the transcription factors NF-kappaB and NF-IL-6. Inhibition of particle phagocytosis did not block activation of the transcription factors. However, inhibition of tyrosine and serine/threonine kinase activity decreased the activation of NF-kappaB and NF-IL-6.These data suggest that particle induced macrophage release of TNF-alpha and IL-6 does not require phagocytosis but is dependent on tyrosine and serine/threonine kinase activity culminating in activation of

    View details for PubMedID 10360689

  • Induction of macrophage C-C chemokine expression by titanium alloy and bone cement particles. journal of bone and joint surgery. British volume Nakashima, Y., Sun, D. H., Trindade, M. C., Chun, L. E., Song, Y., Goodman, S. B., Schurman, D. J., Maloney, W. J., Smith, R. L. 1999; 81 (1): 155-162

    Abstract

    Particulate wear debris is associated with periprosthetic inflammation and loosening in total joint arthroplasty. We tested the effects of titanium alloy (Ti-alloy) and PMMA particles on monocyte/macrophage expression of the C-C chemokines, monocyte chemoattractant protein-1 (MCP-1), monocyte inflammatory protein-1 alpha (MIP-1alpha), and regulated upon activation normal T expressed and secreted protein (RANTES). Periprosthetic granulomatous tissue was analysed for expression of macrophage chemokines by immunohistochemistry. Chemokine expression in human monocytes/macrophages exposed to Ti-alloy and PMMA particles in vitro was determined by RT-PCR, ELISA and monocyte migration. We observed MCP-1 and MIP-1alpha expression in all tissue samples from failed arthroplasties. Ti-alloy and PMMA particles increased expression of MCP-1 and MIP-1alpha in macrophages in vitro in a dose- and time-dependent manner whereas RANTES was not detected. mRNA signal levels for MCP-1 and MIP-1alpha were also observed in cells after exposure to particles. Monocyte migration was stimulated by culture medium collected from macrophages exposed to Ti-alloy and PMMA particles. Antibodies to MCP-1 and MIP-1alpha inhibited chemotactic activity of the culture medium samples. Release of C-C chemokines by macrophages in response to wear particles may contribute to chronic inflammation at the bone-implant interface in total joint arthroplasty.

    View details for PubMedID 10068024

  • A new classification system for the management of acetabular osteolysis after total hip arthroplasty. Instructional course lectures Rubash, H. E., Sinha, R. K., Paprosky, W., Engh, C. A., Maloney, W. J. 1999; 48: 37-42

    View details for PubMedID 10098026

  • Adhesion and reliability of interfaces in cemented total joint arthroplasties JOURNAL OF ORTHOPAEDIC RESEARCH Ohashi, K. L., Romero, A. C., McGowan, P. D., Maloney, W. J., Dauskardt, R. H. 1998; 16 (6): 705-714

    Abstract

    Debonding of the prosthetic/polymethylmethacrylate interface has been implicated in the initial failure process of cemented total hip arthroplasties. However, little quantitative understanding of the debonding process, as well as of the optimum interface morphology for enhanced resistance to debonding, exists. Accordingly, a fracture-mechanics approach has been used in which adhesion at the interface is characterized in terms of the interface fracture energy, G (J/m2), and shown to be a strong function of the morphology, debonding length, and loading mode of the interface. Double-cantilever-beam and four-point-flexure fracture-mechanics samples containing four clinically relevant prosthetic surface preparations were prepared to survey a range of interface roughness and loading modes. Adhesion at the interface could not be characterized with a single-valued material property but was found to exhibit resistance-curve behavior in which resistance to debonding increased with both the initial debond extension and the roughness of the interface. Values of debonding initiation, Go, were relatively insensitive to the roughness of the surface and the loading mode, whereas steady-state fracture resistance of the interface, Gss, increased significantly with the roughness and shear loading of the interface. These quantitative results suggest that debonding of the prosthetic/polymethylmethacrylate interface may be primarily attributed to surface interactions such as interlocking and the pullout of rough asperities that occur behind the debond tip. A simple mechanics analysis of such interactions was performed and revealed increases in the fracture resistance of the interface that were consistent with experimentally measured values.

    View details for Web of Science ID 000077786300011

    View details for PubMedID 9877395

  • Importance of a thin cement mantle - Autopsy studies of eight hips CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Kawate, K., Maloney, W. J., Bragdon, C. R., Biggs, S. A., Jasty, M., Harris, W. H. 1998: 70-76

    Abstract

    The question whether thin cement mantles around cemented femoral components led to an increased frequency of cracks in the cement was asked. Microscopically, multiple cross sections of eight femurs retrieved at autopsy from clinically successful total hip replacements after prolonged in vivo service containing well fixed Harris Design 2 cemented femoral components were studied. None of the components were loose by radiographic criteria. All were fixed solidly when loaded in vitro in simulated stair climbing and gait, as assessed by high resolution micromotion sensors. The specimens were sectioned transversely at 5-mm increments. The cross sections were examined under a dissecting microscope at x 100. A thin mantle arbitrarily was defined as a mantle of less than 1 mm in thickness. The analysis of the contact radiographs showed that the routine anteroposterior and lateral radiographs underestimated the prevalence of thin cement mantles and mantle defects. Although overall on all the cross sections 9% of the aggregated cement mantles was classified as having thin cement, 92 of the 101 cement cracks occurred in areas of the mantles that were less than 1 mm thick.

    View details for Web of Science ID 000077148700008

    View details for PubMedID 9917592

  • Cemented femoral component surface finish mechanics CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Crowninshield, R. D., Jennings, J. D., Laurent, M. L., Maloney, W. J. 1998: 90-102

    Abstract

    A cemented femoral component's surface finish may influence implant function through variations in cement adhesion and abrasion properties. Morphologic characterization of historic and current femoral hip prosthesis surface finishes show greater than x 20 range in implant roughness. Early implants typically had relatively smooth surfaces, whereas many of the more recent implants have rougher surface finishes. Smoother implant surfaces have lower cement-metal interface fixation strength, whereas rougher surfaces have greater fixation strength. With interface motion, the smoother surfaces are less abrasive of bone cement, whereas rougher implant surfaces are more abrasive. Because of enhanced bone cement attachment, rougher implant surfaces may have a lower probability of interface motion, while at the same time, a higher debris generation consequence if motion occurs. In contrast, smoother implant surfaces may have a higher probability of interface motion with a lower debris generating consequence of that motion. The prolonged use of cemented total hip replacement may be approached by either extending the duration of implant function after cement-metal interface loosening with smooth surfaced implants or, in contrast, by extending the duration of cement-metal interface adhesion with rougher surfaced implants.

    View details for Web of Science ID 000077148700010

    View details for PubMedID 9917594

  • Osteolysis in association with a total hip arthroplasty with ceramic bearing surfaces. journal of bone and joint surgery. American volume Yoon, T. R., Rowe, S. M., Jung, S. T., Seon, K. J., Maloney, W. J. 1998; 80 (10): 1459-1468

    Abstract

    The results of 103 total hip arthroplasties performed with insertion of a ceramic femoral head and acetabular component in ninety-six patients were reviewed to determine the radiographic prevalence of osteolysis. After a mean duration of follow-up of ninety-two months (range, sixty to 125 months), femoral osteolysis was observed in twenty-three hips (22 per cent), in one of two distinct patterns: linear osteolysis (twelve hips) or scalloping expansile-type osteolysis (eleven hips). The most common locations of osteolysis in the femur were in zones I and VII as described by Gruen et al. Serial radiographs demonstrated that the extent of the osteolysis progressed over time. Osteolysis of the pelvis, noted in forty-nine hips, was always associated with migration of the acetabular socket. No focal osteolysis was observed in association with the stable sockets. Ten patients (ten hips) had a revision because of loosening and migration of the acetabular component. In three of these patients, the femoral stem also was revised. Gross examination revealed evidence of wear of the ceramic bearing surface in all ten patients. Scanning electron microscopy showed cracking and wear marks on the weight-bearing surface. Histological evaluation of the tissue in the periprosthetic membrane demonstrated abundant ceramic wear particles. The interface membrane was composed of a vascularized fibrous connective tissue with macrophages. Ultrastructurally, the macrophages contained numerous phagosomes of various sizes, with electron-dense material within the cytoplasm of the cell. The mean size of the ceramic particles, as determined with scanning electron microscopy, was 0.71 micrometer (range, 0.13 to 7.20 micrometers). This study supports the concept that ceramic wear particles can stimulate a foreign-body response and periprosthetic osteolysis.

    View details for PubMedID 9801214

  • Effects of serum protein opsonization on cytokine release by titanium-alloy particles JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Maloney, W. J., Sun, D. H., Nakashima, Y., James, R., Smith, R. L. 1998; 41 (3): 371-376

    Abstract

    This study tested whether macrophages respond differently to retrieved titanium-alloy particles than they do to machined titanium-alloy particles and assessed whether pretreatment of machined titanium-alloy particles with human serum would influence macrophage activation and cytokine release in vitro. Human monocyte/macrophages were isolated from normal healthy donors and exposed to increasing concentrations of machined and retrieved titanium-alloy particles. The profile of cytokine release was determined by commercially available ELISA kits. Machined titanium-alloy particles were opsonized with human serum and added to macrophage cultures. Serum protein binding was confirmed by SDS-PAGE analysis. The results showed that machined titanium-alloy particles and retrieved titanium-alloy particles stimulate a similar level of cytokine release when tested at comparable concentrations. Opsonization of the machined particles with human serum increased the macrophage release of cytokines in the first 12 h after exposure compared to nonopsonized particles. At 24 h, the opsonized particles stimulated significantly higher levels of cytokine release, but only at the greatest particle concentrations. This study demonstrates that machined titanium alloy induces a metabolic response in macrophages similar to that of titanium-alloy particles retrieved from failed total hip arthroplasty. In addition, these data show that serum protein binding to orthopedic biomaterial debris alters the macrophage reaction to the particles.

    View details for Web of Science ID 000074523300005

    View details for PubMedID 9659605

  • Induction of matrix metalloproteinase expression in human macrophages by orthopaedic particulate debris in vitro. journal of bone and joint surgery. British volume Nakashima, Y., Sun, D. H., Maloney, W. J., Goodman, S. B., Schurman, D. J., Smith, R. L. 1998; 80 (4): 694-700

    Abstract

    We exposed human macrophages isolated from the peripheral blood of healthy donors to metal and bone-cement particles from 0.2 to 10 microm in size. Zymography showed that macrophages exposed to titanium alloy and polymethylmethacrylate (PMMA) particles released a 92- and 72-kDa gelatinase in a dose- and time-dependent manner. Western immunoblotting confirmed that the 92- and 72-kDa gelatinolytic activities corresponded to matrix metalloproteinase-9 and matrix metalloproteinase-2 (MMP-9, MMP-2), respectively. Western immunoblotting also indicated that titanium alloy and PMMA particles increased the release of MMP-1. Northern blotting showed elevated mRNA signal levels for MMP-1, MMP-2, and MMP-9 after exposure to both types of particle. Collagenolytic activity also increased in the macrophage culture medium in response to both types of particle. Our findings support the hypothesis that macrophages release MMPs in proportion to the amount of particulate debris within periprosthetic tissues.

    View details for PubMedID 9699840

  • Deep venous thrombosis prophylaxis for knee replacement: warfarin and pneumatic compression. American journal of orthopedics (Belle Mead, N.J.) Woolson, S. T., Robinson, R. K., Khan, N. Q., Roqers, B. S., Maloney, W. J. 1998; 27 (4): 299-304

    Abstract

    A prospective study of the prevalence of proximal deep venous thrombosis in total knee replacement patients who had prophylaxis for thrombosis with a combination of low-dose warfarin and intermittent pneumatic compression was done. Two hundred and ninety-seven patients who underwent 377 consecutive total knee replacements were studied. All patients were treated with low-dose warfarin and intermittent pneumatic compression using thigh-high sleeves. Surveillance for proximal thrombosis was done by duplex ultrasonography. Proximal thrombosis was detected in 19 patients, for a prevalence of 5%. There were 3 patients who had a major bleeding complication, for a prevalence of 0.9% for the 337 procedures performed. Although there was no concurrent control group of patients treated with another means of prophylaxis to compare with these patients, the low prevalence of proximal thrombosis and the low risk of major bleeding complications that was found compares well with recent reports on the effectiveness and safety of low-molecular-weight heparin.

    View details for PubMedID 9586729

  • Factor V Leiden and the risk of proximal venous thrombosis after total hip arthroplasty JOURNAL OF ARTHROPLASTY Woolson, S. T., Zehnder, J. L., Maloney, W. J. 1998; 13 (2): 207-210

    Abstract

    Deep vein thrombosis (DVT) remains a major cause of morbidity in patients undergoing total hip arthroplasty (THA). Despite postoperative DVT prophylaxis, 20-50% of THA patients still develop DVT. Currently, there is no accurate way of predicting which patients will develop DVT despite standard prophylaxis. The presence of factor V Leiden is the most common cause of inherited DVT risk. It has been postulated that patients who have factor V Leiden and are subjected to thrombogenic stressors such as THA would have an increased risk of thrombosis. The factor V Leiden genotype of 36 patients who developed proximal DVT after surgery and 45 control patients who had THA but did not develop DVT was determined. All patients had had prophylaxis against thrombosis using intermittent pneumatic compression alone or in combination with warfarin or aspirin. Surveillance for proximal DVT was performed on all patients prior to discharge by duplex ultrasound. The 2 groups were similar in age, sex, and type of operation. Three of 36 study patients who had developed DVT (8%) and 2 of 45 control patients who had not developed DVT (4%) were heterozygotes for factor V Leiden; these prevalences were not statistically different. Heterozygosity for factor V Leiden is not associated with DVT prophylaxis failure in patients undergoing THA.

    View details for Web of Science ID 000072498700014

    View details for PubMedID 9526216

  • Osteolysis: Cause and effect INSTRUCTIONAL COURSE LECTURES, VOL 47 - 1998 Sinha, R. K., Shanbhag, A. S., Maloney, W. J., Hasselman, C. T., Rubash, H. E. 1998; 47: 307-320

    View details for Web of Science ID 000074947000036

    View details for PubMedID 9571432

  • Osteolysis: Surgical treatment INSTRUCTIONAL COURSE LECTURES, VOL 47 - 1998 Rubash, H. E., Sinha, R. K., Maloney, W. J., Paprosky, W. G. 1998; 47: 321-329

    View details for Web of Science ID 000074947000037

    View details for PubMedID 9571433

  • Fatigue fracture of a forged cobalt-chromium-molybdenum femoral component inserted with cement. A report of ten cases. journal of bone and joint surgery. American volume Woolson, S. T., Milbauer, J. P., Bobyn, J. D., Yue, S., Maloney, W. J. 1997; 79 (12): 1842-1848

    Abstract

    Ten patients who had had a total hip replacement with a forged cobalt-chromium-molybdenum femoral prosthesis (Precoat or Precoat Plus) inserted with cement were seen with a fatigue fracture of the stem an average of fifty months (range, nineteen to seventy-four months) postoperatively. The average age of the patients was sixty-one years (range, forty-three to seventy-three years), and the average weight was ninety-six kilograms (range, seventy to 130 kilograms). Eight patients had had a primary total hip replacement, and two had had a revision; all of the acetabular components had been inserted without cement. Radiographs that had been made before the fracture were available for four of the eight hips that had had a primary replacement; all four had radiographic evidence of debonding of the cement mantle from the proximal end of the stem. This probably caused exaggerated cantilever bending stresses on the proximal aspect of the stem as the distal end of the stem was well fixed. The radiographs of both hips that had had a revision demonstrated a non-union of the greater trochanter, which had resulted in separation at the cement-bone interface at the proximal portion of the femur before the fracture. Scanning electron micrographs of five of the ten fractured prostheses demonstrated a fatigue fracture that began near the anterolateral corner of the prosthesis, through characters that had been etched on the implant with a laser. Metallurgical analysis indicated subsurface voids or inclusions, or both, immediately under the region that had been etched. This finding is consistent with thermal changes to the microstructure of the alloy that probably caused a focal reduction in the material strength. A high proportion (seven) of the ten stems had a poor cement mantle. Also, of the seven small stems that were used, six had been implanted in patients who weighed more than eighty kilograms, so there was relative undersizing of the prostheses. Early debonding of the proximal end of a Precoat femoral prosthesis from the cement mantle may occur as a result of a thin cement mantle, leading to loosening and possibly to early fatigue fracture of the stem if the distal portion of the stem remains solidly fixed in the distal portion of the cement column. On the basis of our experience, we recommend that patients who have radiographic evidence of a debonded Precoat femoral component should be informed of the risk of fatigue fracture of the stem and be followed closely even though there may be no symptoms of loosening of the femoral component.

    View details for PubMedID 9409798

  • Treatment of pelvic osteolysis associated with a stable acetabular component inserted without cement as part of a total hip replacement. journal of bone and joint surgery. American volume Maloney, W. J., Herzwurm, P., Paprosky, W., Rubash, H. E., Engh, C. A. 1997; 79 (11): 1628-1634

    Abstract

    Thirty-five patients who had had a primary total hip replacement with a porous-coated acetabular component inserted without cement had a revision procedure to treat pelvic osteolysis. The mean age at the time of the revision operation was forty-nine years (range, twenty-nine to eighty-five years). Forty-six distinct pelvic osteolytic lesions were noted radiographically around the thirty-five cups. These lesions ranged in size from 0.5 by 0.5 centimeter to 6.3 by 2.7 centimeters (mean, 2.6 by 1.7 centimeters). Fourteen of the thirty-five patients had no or only slight occasional pain at the time of diagnosis of the pelvic osteolysis, fifteen patients had pain attributed to a loose femoral component, one had pain related to a spontaneous fracture of the greater trochanter, and one had pain related to recurrent subluxation. The remaining four patients had pain in the groin despite radiographically stable implants. All of the metal-backed porous-coated acetabular components were stable according to the preoperative radiographs, and the stability was confirmed at the time of the revision. The metal shell was left in place and the acetabular liner was exchanged in all thirty-five patients. The osteolytic lesions were debrided, and thirty-four of the forty-six lesions were filled with allograft bone chips. The patients were evaluated a minimum of two years (range, two to five years; mean, 3.3 years) after the revision operation, and all thirty-five sockets were found to be radiographically stable. The bone grafts appeared to have consolidated, and none of the osteolytic defects had progressed. One-third of the lesions were no longer visible on radiographs, regardless of whether or not they had been filled with bone graft. The remaining lesions had decreased in size. It appears that, in the short-term, exchange of the liner and debridement of the granuloma, with or without use of allograft bone chips in the osteolytic defect, is a reasonable alternative to revision of the socket provided that the metal shell is solidly fixed at the time of the revision operation. If the metal shell has been markedly damaged by the femoral head, the locking mechanism for the polyethylene liner is not intact, or a satisfactory replacement liner is not available, then revision of the porous-coated acetabular component is indicated. These results must be considered preliminary. Since osteolysis may take several years to redevelop after a revision, additional follow-up is required.

    View details for PubMedID 9384421

  • The Otto Aufranc Award. Skeletal response to well fixed femoral components inserted with and without cement. Clinical orthopaedics and related research Maloney, W. J., Sychterz, C., Bragdon, C., McGovern, T., Jasty, M., Engh, C. A., Harris, W. H. 1996: 15-26

    Abstract

    Previous studies evaluating femoral remodeling after total hip arthroplasty have used clinical radiographs and dual energy xray absorptiometry. Limitation of these techniques make it impossible to quantify the magnitude of bone loss in terms of cortical thinning and cortical bone area and bone mineral density changes. Femoral cortical bone remodeling after cemented and cementless replacement was quantified and possible determinants of bone remodeling in terms of clinical and radiographic variables were evaluated. Forty-eight anatomic specimen femora from 24 patients with unilateral cemented and cementless hip replacements were analyzed. Cortical thickness, cortical bone area, and bone mineral density was assessed in 4 quadrants at 5 discrete levels. The maximum cortical bone loss by level was at the middle section for the cemented femurs and at the midproximal and middle sections for the cementless femurs. However, if one examines individual quadrants, the proximal medial cortex still represents the specific region of maximal bone loss for both types of implant fixation. The posterior cortex had substantially more bone loss, even in the diaphyseal levels, than had been previously appreciated. A strong correlation was noted between the bone mineral density of the control femur and the percentage decrease of bone mineral density in the remodeled femur. Based on this data, it seems that the less dense the bone is before hip replacement surgery, the greater the extent of bone loss after total hip arthroplasty regardless of the fixation type.

    View details for PubMedID 8981879

  • RT-PCR analysis of MMP-9 expression in human articular cartilage chondrocytes and synovial fluid cells BIOTECHNIC & HISTOCHEMISTRY Tsuchiya, K., Maloney, W. J., Vu, T., Hoffman, A. R., Schurman, D. J., Smith, R. L. 1996; 71 (4): 208-213

    Abstract

    This report presents a method for analyzing matrix metalloproteinase-9 (92 kD gelatinase) MMP-9 mRNA expression using reverse transcription polymerase chain reaction (RT-PCR). With this method, chondrocytes isolated from small samples of osteoarthritic cartilage showed significantly elevated signal for MMP-9 mRNA compared to normal cartilage. In addition, cells of synovial fluid samples aspirated from osteoarthritic joints also exhibited MMP-9 expression using this technique. RT-PCR proved to be a sensitive method for assessing MMP-9 regulation in osteoarthritic and normal cartilage, and may provide a useful index of arthritic cartilage and synovial fluid cell metabolism when limited tissue is available.

    View details for Web of Science ID A1996VE64300007

    View details for PubMedID 8874859

  • In vitro activation of human fibroblasts by retrieved titanium alloy wear debris JOURNAL OF ORTHOPAEDIC RESEARCH Manlapaz, M., Maloney, W. J., Smith, R. L. 1996; 14 (3): 465-472

    Abstract

    Titanium-aluminum-vanadium wear particles isolated from the soft-issue membrane of a failed total hip arthroplasty were added to human fibroblasts in cell culture. The cellular response to particle challenge was determined by assaying for levels of interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, prostaglandin E2, basic fibroblast growth factor, platelet-derived growth factor-AB, and transforming growth factor-beta. Collagenase and gelatinase activities were analyzed by zymography and [3H]collagen degradation. Cell viability was assessed by measuring the uptake of [3H]thymidine. Over the range of particle concentrations tested, cell viability, as demonstrated by [3H]thymidine uptake, remained unaffected. Fibroblasts exhibited a dose-dependent release of interleukin-6 in response to exposure to titanium-aluminum-vanadium particles. At 6 and 48 hours, the highest concentration of titanium alloy particles (0.189% [vol/vol]) resulted in 7-fold and 16-fold increases in interleukin-6 release, respectively, when compared with negative controls. Neither interleukin-1 beta nor tumor necrosis factor-alpha was detected in the culture medium at any particle concentration tested for both dermal and foreskin fibroblasts. The pattern of prostaglandin E2 release by fibroblasts mirrored the pattern of interleukin-6 release. Fibroblasts exposed to the highest concentration of titanium alloy particles showed an increase in collagenase activity, starting at 12 hours. When medium samples were treated with amino phenylmercuric acetate to activate latent enzymes, a statistically significant increase in collagenase activity was observed as early as 6 hours (p < 0.001). Substrate gel analysis of medium from fibroblasts stimulated by high particle concentrations also showed an increase in gelatinolytic activity when compared with unstimulated controls. Analysis of medium samples for growth factors showed an increase in basic fibroblast growth factor at low particle concentrations, beginning at 12 hours. Levels of platelet-derived growth factor-AB and transforming growth factor-beta were not detectable in the controls or at any particle concentration tested. The results of this study showed that fibroblasts exposed to titanium alloy wear particles become activated and release proinflammatory mediators that influence bone metabolism. These data support the hypothesis that direct activation of fibroblasts by particulate wear may play a role in particle-mediated osteolysis. Fibroblast activation coupled with the biologic response of macrophages to wear debris in the loosening membrane may have a synergistic effect on pathologic bone resorption.

    View details for Web of Science ID A1996UT65500016

    View details for PubMedID 8676260

  • Chondrocytes from osteoarthritic cartilage have increased expression of insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) and -5, but not IGF-II or IGFBP-4 JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Olney, R. C., Tsuchiya, K., Wilson, D. M., Mohtai, M., Maloney, W. J., Schurman, D. J., Smith, R. L. 1996; 81 (3): 1096-1103

    Abstract

    Osteoarthritis is a disease in which articular cartilage metabolism is altered, leading to cartilage destruction. As insulin-like growth factor-I (IGF-I) is the major anabolic mediator for articular cartilage, and the IGF-binding proteins (IGFBPs) are an integral part of the IGF axis, they may play a role in the pathophysiology of osteoarthritis. Chondrocytes isolated from fibrillated and normal appearing areas of osteoarthritic human cartilage and from normal cartilage were studied for IGF and IGFBP expression. IGF and IGFBP messenger ribonucleic acids were analyzed by a RT-quantitative PCR technique and Northern blotting. In osteoarthritic chondrocytes, IGF-I message was increased 3.5-fold, IGFBP-3 was increased 24-fold, and IGFBP-5 was increased 16-fold over normal chondrocytes. Chondrocytes from normal appearing areas of cartilage from osteoarthritic joints had intermediate levels. Message levels for beta-actin, IGF-II, and IGFBP-4 were unchanged between the cartilage types. IGF and IGFBP production were analyzed by Western ligand blots and RIAs of conditioned medium from cartilage cultured in serum-free conditions. IGF-I was undetectable in conditioned medium from normal cartilage and increased in that from osteoarthritic cartilage. Osteoarthritic cartilage samples produced IGFBP-2, -3, and -4; glycosylated IGFBP-4; and IGFBP-5. IGFBP-2, -3, and -5 production was increased in osteoarthritic cartilage. Proteases with activity against IGFBP-3 and -5 were also produced by osteoarthritic cartilage. The observation that IGFBP-3 and -5 expression and production are elevated in osteoarthritic cartilage suggests that they may be acting as a competitor for IGF-I in osteoarthritic cartilage, thus reducing the anabolic stimulation of this tissue and contributing to the net loss of cartilage in this disease.

    View details for Web of Science ID A1996TZ90600042

    View details for PubMedID 8772582

  • Increasing incidence of femoral osteolysis in association with uncemented Harris-Galante total hip arthroplasty - A follow-up report JOURNAL OF ARTHROPLASTY Maloney, W. J., Woolson, S. T. 1996; 11 (2): 130-134

    Abstract

    Sixty-nine consecutive uncemented total hip arthroplasties were performed in 59 patients using the Harris-Galante prosthesis (Zimmer, Warsaw, IN). The patients were reviewed an average of 44 and 71 months after surgery. Patients in whom femoral osteolysis was identified at the time of the first review were again evaluated at the second review to determine if the size of the osteolytic lesion had increased over time. At the initial review an average of 44 months postsurgery, the overall incidence of femoral osteolysis was 22%. At the second review, the incidence of femoral osteolysis had increased from 22 to 52%. Two thirds of the lytic lesions diagnosed at the time of the first review had increased in size. This study demonstrated that the incidence of femoral osteolysis in cementless hip arthroplasties increases with time and that the majority of existing lesions enlarge over time. Once lesions are identified, more frequent follow-up evaluations are recommended. Revision surgery may be required for progressive femoral osteolysis, despite the absence of significant clinical symptoms.

    View details for Web of Science ID A1996TX39900005

    View details for PubMedID 8648304

  • Human macrophage response to retrieved titanium alloy particles in vitro CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., James, R. E., Smith, R. L. 1996: 268-278

    Abstract

    Titanium alloy particles were isolated from membranes obtained at revision arthroplasty. Addition of these retrieved particles to human monocytes/macrophages in cell culture resulted in morphologic change and metabolic activation. Cells exposed to these particles actively phagocytized the metallic debris, resulting in an increase in cytoplasm and a polarization of ingested metal. The metabolic response of the macrophages included increased release of prostaglandin E2, interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha, and increased hexosaminidase activity. Increased release of interleukin-1 beta was maximal 6 to 12 hours after particle exposure. These data show that retrieved titanium alloy particles activate macrophages in vitro in an analogous fashion to that observed around failed arthroplasties.

    View details for Web of Science ID A1996TP57400032

    View details for PubMedID 8542704

  • ISOLATION AND CHARACTERIZATION OF WEAR PARTICLES GENERATED IN PATIENTS WHO HAVE HAD FAILURE OF A HIP-ARTHROPLASTY WITHOUT CEMENT JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Maloney, W. J., Smith, R. L., Schmalzried, T. P., Chiba, J., HUENE, D., Rubash, H. 1995; 77 (9): 1301-1310

    Abstract

    Wear particles from thirty-five membranes obtained during revision hip-replacement operations were studied after digestion of the soft tissue with papain. The particles were isolated and were characterized with use of light and scanning electron microscopic techniques, x-ray microanalysis, and an automated particle analyzer. The mean size of the polyethylene particles was 0.5 micrometer, and the metal particles were a mean of 0.7 micrometer, as determined with scanning electron microscopy. The automated particle analyzer revealed a mean particle diameter of 0.63 micrometer (more than 90 per cent of all particles were less than 0.95 micrometer) and a mean of 1.7 billion particles per gram of tissue, compared with only 143 million per gram of tissue for the control samples. X-ray microanalysis revealed metal debris in sixteen (46 per cent) of the thirty-five membranes after digestion. Thirteen (50 per cent) of the twenty-six membranes surrounding a titanium-alloy stem contained metal particles, compared with three of the nine membranes surrounding a chromium-cobalt stem. Metal debris was present in only one of the twelve membranes surrounding a titanium-alloy stem without a porous coating, compared with twelve of the fourteen membranes surrounding a titanium-alloy stem with a porous coating. This tenfold difference in prevalence was significant (p < 0.005). On the average, the total number of particles (expressed in millions per gram of tissue) associated with the bipolar acetabular components was twice that associated with the fixed acetabular components. In addition, there was a trend toward a larger mean size of the polyethylene particles in association with the bipolar cups. Our data indicate that particulate prosthetic debris in the tissues around failed femoral components that have been inserted without cement constitutes a class of particles that are predominantly less than one micrometer in size and are present in amounts of more than one billion particles per gram of tissue. Routine histological methods did not detect this class of wear debris and led to a gross underestimation of the amount of debris in these membranes.

    View details for Web of Science ID A1995RV56800002

    View details for PubMedID 7673277

  • COMPENSATING FOR CHANGES IN MUSCLE LENGTH IN TOTAL HIP-ARTHROPLASTY - EFFECTS ON THE MOMENT GENERATING CAPACITY OF THE MUSCLES CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Vasavada, A. N., Delp, S. L., Maloney, W. J., Schurman, D. J., Zajac, F. E. 1994: 121-133

    Abstract

    Alterations in the location of the hip center may change the lengths and moment arms of the muscles, and thereby affect their capacity to generate force and moment about the hip. This study demonstrates some of the differences between compensating and not compensating for changes in muscle length that arise from displacement of the hip center. A computer model was developed to estimate the maximum isometric moment generating capacity of the hip muscles under two conditions. In the compensated condition, the hip center was displaced, but the muscles were restored to their original lengths and orientations by altering proximal femoral geometry. In the uncompensated condition, femoral geometry remained constant; thus, muscle lengths and orientations changed with displacement of the hip center. The computer simulations showed large differences between the two conditions. For example, a 2-cm superior displacement of the hip center decreased the moment generating capacity of the hip abductors 18% with compensation and 49% without compensation. Similarly, a 1-cm medial displacement of the hip center increased the moment generating capacity of the abductors 17% with compensation, but decreased it 4% without compensation. In contrast, a 1-cm inferior displacement decreased the moment generating capacity of flexors 6% with compensation, but increased it 12% without compensation. The results presented here demonstrate that compensating for changes in muscle length can be important in terms of preserving the moment generating capacity of the muscles when the hip center is displaced superiorly and medially, but not when the hip center is displaced in the inferior direction.

    View details for Web of Science ID A1994NL07400020

    View details for PubMedID 8168289

  • A quantitative in vitro assessment of fit and screw fixation on the stability of a cementless hemispherical acetabular component. journal of arthroplasty Kwong, L. M., O'Connor, D. O., SEDLACEK, R. C., Krushell, R. J., Maloney, W. J., Harris, W. H. 1994; 9 (2): 163-170

    Abstract

    This investigation quantifies in vitro the effect of component fit, as well as the effect of adjuvant screw fixation, on the initial stability of cementless hemispherical titanium acetabular total hip arthroplasty components and assesses apposition of the acetabular components to bone. Six, fresh human hemipelvi (3 matched pairs) were harvested at autopsy. Titanium alloy acetabular components with a porous surface of commercially pure titanium fiber mesh (Harris Galante Porous acetabular components, Zimmer, Warsaw, IN) were used for implantation. Initially, each acetabulum was underreamed to achieve a 2 mm press-fit with the acetabular component. Pressure-sensitive film had been placed along the dome and medial wall at the bone-implant interface to assess the completeness of seating. After the implant was impacted into the acetabular cavity, relative motion between the implant and bone was measured during simulated single leg stance. Adjuvant fixation of the implant was then obtained with the insertion of four 6.5 mm cancellous screws. High-contrast roentgenograms of the specimens in multiple views were obtained after initial cup insertion and again after screw insertion. The stability of each implant under load was measured with four, three, two, one, and no screws in place. Further reaming of the bone was done to create a 1 mm press-fit. The sequence was then repeated. Further reaming was done to create an exact-fit and the sequence was repeated again. Under these conditions, 1 mm press-fit with or without screws provided the optimum combination of fit stability.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for PubMedID 8014647

  • Severe osteolysis of the pelvic in association with acetabular replacement without cement. journal of bone and joint surgery. American volume Maloney, W. J., Peters, P., Engh, C. A., Chandler, H. 1993; 75 (11): 1627-1635

    Abstract

    We reviewed the cases of fourteen patients (fifteen lesions) who had osteolysis following the replacement of the acetabulum without cement. Nine women and five men, seventeen to sixty-seven years old, were involved in the study. One woman had bilateral pelvic osteolysis. Eight of the fifteen index acetabular reconstructions were done with a titanium-alloy implant and seven, with a chromium-cobalt-alloy implant. Eleven of the fifteen acetabular components had holes in the metal shell that may have acted as a conduit through which wear debris could gain access to the implant-bone interface, but only two of the acetabular components had been fixed with screws. In these two acetabular components, all available screw holes were not filled. The polyethylene liner was eight millimeters thick or less in twelve of the fifteen acetabular components; all of the liners were ten millimeters thick or less. The diameter of the head of eleven of the fifteen femoral components was thirty-two millimeters. Fourteen of the fifteen femoral components were placed without cement, and all but one was radiographically stable. The duration from the index operation to the appearance of pelvic osteolysis ranged from fifty-three to eighty-four months (mean, sixty-five months). At the time of the diagnosis, the patients were functioning well clinically, and all but three had a Harris hip score of 90 points or better, despite extensive destruction of bone in some instances. Since these patients were functioning well, the pelvic osteolysis was diagnosed radiographically at a regular follow-up examination. Only one patient had evidence of migration of the acetabular component on serial radiographs.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for PubMedID 8245055

  • Fibroblast response to metallic debris in vitro. Enzyme induction cell proliferation, and toxicity. journal of bone and joint surgery. American volume Maloney, W. J., Smith, R. L., CASTRO, F., Schurman, D. J. 1993; 75 (6): 835-844

    Abstract

    Bovine synovial fibroblasts in primary monolayer culture were exposed to particulate metallic debris. The effects of the metallic particles on the synthesis and secretion of proteolytic enzymes and on cell proliferation and viability were examined. Uniform suspensions of titanium, titanium-aluminum, cobalt, and chromium particles, ranging in size from approximately 0.1 to ten micrometers (average, one to three micrometers), were prepared; the particle concentrations (the volume of particles divided by the total volume of the suspension) ranged from 0.0005 to 5 per cent. Aliquots of the particle suspensions were added to the synovial fibroblast cultures. The final particle concentrations in the media ranged from 0.0000083 to 0.83 per cent. After seventy-two hours of exposure, each medium was harvested and was assayed for proteolytic and collagenolytic activity and for hexosaminidase levels. Neutral metalloproteases, quantified by collagenolytic and caseinolytic (proteolytic) activity, represent enzymes, secreted by cells, that are capable of degrading extracellular matrix. Hexosaminidase is a marker for lysosomal enzyme activity that can include more than thirty enzymes, such as proteases, lipases, nucleases, and phosphatases. Cell proliferation was quantified by uptake of 3H-thymidine. Cell morphology was examined by scanning electron microscopy. Titanium, titanium-aluminum, and chromium significantly stimulated 3H-thymidine uptake at low particle concentrations (p < 0.01, p < 0.002, and p < 0.002, respectively). Exposure to cobalt, even at the lowest particle concentration, resulted in a significant decrease in thymidine uptake (p = 0.027). At the highest particle concentrations, all particles were toxic, as evidenced by the absence of thymidine uptake. At high particle concentrations, all of the metals caused a decrease in caseinolytic (proteolytic) and collagenolytic activity in the culture media. Titanium elevated the lysosomal enzyme marker, hexosaminidase, except at high concentrations. Chromium and titanium-aluminum had no significant effect on hexosaminidase at any particle concentration, while cobalt decreased all enzyme markers at mid-particle to high-particle concentrations. Scanning electron microscopy demonstrated that the morphological response of fibroblasts to titanium included membrane-ruffling and extension of filopodia, typical of active fibroblasts. In contrast, exposure to cobalt at the same concentration resulted in cell crenation, indicative of cell death.

    View details for PubMedID 8314824

  • SEGMENTAL CEMENT EXTRACTION AT REVISION TOTAL HIP-ARTHROPLASTY CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Schurman, D. J., Maloney, W. J. 1992: 158-163

    Abstract

    Cement removal in revision total hip arthroplasty can be technically challenging. Traditional methods involve using a combination of chisels, power burrs, and drills, as well as windowing the femoral cortex to gain access to cement distally. These methods can be associated with femoral fracture or uncontrolled cortical perforation and bone loss. A new technique had been developed that permits segmental extraction of bone cement from the femoral canal. Fresh cement is introduced into the old cement mantle and a threaded rod is placed into the wet cement and held in place while the cement hardens. The thread-forming rod is then removed leaving a threaded channel in the cement. Extraction rods are then screwed 1.5 to 2.5 cm into the threaded channel. A slap hammer, which attaches to the opposite end of the extraction rod, is used to remove 1.5- to 2.5-cm segments of cement. Fifteen cases involving revision of cemented femoral components were analyzed using this system. Complete cement removal was achieved in 12 cases with much less damage to the femur when compared with conventional methods. In two cases, there was retained cement along the medial wall of the femur and, in one case, the plug could not be extracted using this system. There were no fractures or cortical perforations in this series.

    View details for Web of Science ID A1992KB63200021

    View details for PubMedID 1446433

  • Bone ingrowth into a low-modulus composite plastic porous-coated canine femoral component. journal of arthroplasty Jasty, M., Bragdon, C. R., Maloney, W. J., Mulroy, R., HAIRE, T., Crowninshield, R. D., Harris, W. H. 1992; 7 (3): 253-259

    Abstract

    Bone ingrowth into low-modulus canine femoral components made of composite plastics and porous coated with titanium fiber mesh was evaluated and compared to that found in femoral components of the same design made of titanium alloy and porous coated with titanium fiber mesh. Both types of components demonstrated extensive bone ingrowth into the porous coatings at 6 weeks and there were no differences in the histologic appearance of the tissue ingrowth in the two groups. The amount of bone that grew into the porous surface, the areal density of bone within the available pore space, and the extent of the prosthesis periphery with bone ingrowth were not significantly varied in the two different components. The results of this study show that adequate fixation of low-modulus composite femoral components porous coated with titanium fiber mesh by bone ingrowth can occur and that further investigation of these materials for femoral components may be warranted.

    View details for PubMedID 1402939

  • BEAD LOOSENING FROM A POROUS-COATED ACETABULAR COMPONENT - A FOLLOW-UP NOTE CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Davey, J. R., Harris, W. H. 1992: 112-114

    Abstract

    Beaded porous-coated implants are commonly used in total joint arthroplasty. In this study, the authors extended the follow-up period for the Davey and Harris study of bead loosening in beaded cementless acetabular components. When 56 primary total hip arthroplasties were first reviewed, at an average of 2.5 years after surgery, the incidence of bead loosening was 8.9%. Reevaluation at a mean of 4.5 years after surgery revealed that the incidence of loosening had increased to 19.6%. Bead loosening was associated with acetabular migration in one component and a broken screw in a second. In the absence of loose beads, there were no broken fixation screws or socket migration. Radiolucencies at the bone-implant interface were seen in association with loose beads in only one case. Although long-term implications of bead loosening are not clear, bead migration may increase the possibility of macrophage response to metallic debris.

    View details for Web of Science ID A1992JG97700019

    View details for PubMedID 1499196

  • PROPHYLAXIS FOR HETEROTOPIC BONE-FORMATION AFTER TOTAL HIP-ARTHROPLASTY USING LOW-DOSE RADIATION IN HIGH-RISK PATIENTS CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Jasty, M., Willett, C., MULROY, R. D., Harris, W. H. 1992: 230-234

    Abstract

    Fifteen consecutive total hip arthroplasties (THAs) in 14 patients considered at risk for developing significant heterotopic ossification (HO) were treated postoperatively with 7.5 Gy of external beam radiation in three fractions. Eight hips in eight of the patients (Group I) had developed previous Brooker Class III or IV HO after THA and were radiated after having excision of HO in conjunction with a revision THA. Three additional hips in three patients (Group II) were radiated after primary THA, because they developed significant HO on the contralateral hip after a previous THA. The remaining four hips in three patients (Group III) were radiated after primary THA because they had bilateral hypertrophic arthritis. Precision shielding was employed to minimize the volume of tissue in the radiation field and to protect the bone-implant interface around porous-coated components and the trochanteric osteotomy sites. Of the eight hips in which Class III or IV bone was excised during revision THA (Group I), no new bone formed in five hips and in the other three hips, only Class I bone formed. No heterotopic bone formed in the remaining seven hips of Groups II and III. All six trochanteric osteotomies healed. There were no wound healing problems. There were no significant radiolucencies around any of the components and there was no radiographic evidence of implant instability. This regimen using 7.5 Gy over three fractions minimizes the radiobiologic impact, whereas the use of precision shielding minimizes the total volume of tissue treated. This regimen is an effective means of preventing significant HO after THA in high-risk patients while minimizing radiation exposure.

    View details for Web of Science ID A1992JC24600030

    View details for PubMedID 1611750

  • THE EFFECTS OF IMPLANT DESIGN ON RANGE OF MOTION AFTER TOTAL KNEE ARTHROPLASTY - TOTAL CONDYLAR VERSUS POSTERIOR STABILIZED TOTAL CONDYLAR DESIGNS CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Schurman, D. J. 1992: 147-152

    Abstract

    Range of motion (ROM) after total knee arthroplasty (TKA) is an important variable in determining clinical outcome. Recent design modifications have been aimed at improving final motion. The posterior stabilized total knee prosthesis was introduced as a modification of the total condylar design, changing the center of curvature of the femoral component to allow greater ROM. In this study, all primary TKAs performed at the authors' institution from July 1982 until December 1986 were reviewed to determine the effect of this design modification on outcome. A total condylar (TC) group comprised 51 arthroplasties and was compared to 53 arthroplasties in a posterior stabilized (PSTC) group. the postoperative protocol was identical in both groups. The mean postoperative flexion was 11 better in the PSTC group; however, the mean preoperative flexion had initially been 10 degrees better in the PSTC group. The maximum flexion achieved by any patient in both groups was similar, but the TC group actually gained slightly more arc of motion. The better motion in the PSTC group may be secondary to better motion preoperatively and not implant design in this series. The more limited the preoperative ROM, the greater the quadriceps stiffness is likely to be, which is an important determinant of postoperative flexion. Review of the literature supports present observations that a group with less mean preoperative motion paradoxically gains a slightly greater increment of flexion. Differences in flexion after TKA are difficult to attribute to design in either the current study or by a review of the literature. This is because determinants of flexion after TKA are multifactorial and outcome data limited, notwithstanding the similarities among modern prostheses.

    View details for Web of Science ID A1992HR56200024

    View details for PubMedID 1563146

  • The progression of femoral cortical osteolysis in association with total hip arthroplasty without cement. journal of bone and joint surgery. American volume Tanzer, M., Maloney, W. J., Jasty, M., Harris, W. H. 1992; 74 (3): 404-410

    Abstract

    Twenty hips in twenty patients had development of femoral endosteal cortical erosion after a cementless total hip replacement with the Harris-Galante porous-coated implant. Serial anteroposterior and lateral radiographs of all of the affected femora were reviewed to determine the interval between the operation and the first recognition of the osteolytic lesion or lesions, as well as to evaluate the radiographic appearance and progression of the lesions. The twenty affected hips were followed for an average of fifty-three months (range, twenty to seventy-seven months) after the operation. Osteolysis was first noted radiographically at twelve to sixty-six months (mean, thirty-nine months) postoperatively; in most patients, it occurred around the distal portion of the prosthetic stem. Twelve (60 per cent) of the femoral components were shown to be loose, as proved either radiographically or operatively. Three of these components had been judged radiographically to be stable when the endosteal erosion had first been identified, but they had subsequently migrated. The remaining eight hips had no evidence of loosening. The osteolysis was more severe in the femora in which the component was loose than in those in which it was stable. Of the fourteen patients who were followed, twelve (86 per cent) had an increase in the size of the osteolytic lesions with time, and only one patient had some radiographic evidence of healing.

    View details for PubMedID 1548268

  • THE HISTOLOGY OF THE RADIOLUCENT LINE JOURNAL OF BONE AND JOINT SURGERY-BRITISH VOLUME Kwong, L. M., Jasty, M., MULROY, R. D., Maloney, W. J., Bragdon, C., Harris, W. H. 1992; 74 (1): 67-73

    Abstract

    The radiographic and histological features of radiolucent areas at the cement-bone interface were correlated in 15 specimens retrieved at post-mortem from patients who had undergone cemented total hip arthroplasty, two weeks to 15 years prior to death. All but one of the components were securely fixed, as demonstrated by direct measurements of micromotion. Extensive radiolucencies were present in all but one case. In 11 of the 14 specimens with radiolucencies, histological examination showed that the radiolucent areas represented regions of osteoporosis and bone remodelling. The remodelling changes were characterised by osteoporosis, cancellisation and thinning of the endosteal cortex, and osteopenia of the trabecular bone. In two specimens the appearance of radiolucency was found to be due to fibrous tissue at the cement-bone interface and in one specimen there was a mixed picture of osteolysis and fibrosis. The study demonstrates that radiolucent lines can occur with well-fixed components and that they may commonly represent osteoporosis rather than the presence of a fibrous membrane at the cement-bone interface.

    View details for Web of Science ID A1992HA16800017

    View details for PubMedID 1732269

  • Cementless total hip arthroplasty using a porous-coated prosthesis for bone ingrowth fixation. 3 1/2-year follow-up. journal of arthroplasty Woolson, S. T., Maloney, W. J. 1992; 7: 381-388

    Abstract

    The clinical and radiologic results of a consecutive series of 59 patients (69 hips) who had primary total hip arthroplasty using cementless prostheses was studied. Harris-Galante acetabular and femoral prostheses, which have a porous fiber-metal mesh coating intended to encourage bone ingrowth fixation, were used in all cases. Two femoral components were revised during the follow-up period, one for aseptic loosening and the other for late septic loosening. In the remaining 67 hips, the average Harris hip score rose from a preoperative 52 to 94 at the last follow-up examination (average follow-up period, 44 months). Eighty-eight percent of these hips had an excellent result (Harris hip score of 90 or more). Radiologic analysis demonstrated that all the acetabular components were stable. Eighty-three percent of the femoral components appeared to have stable bone ingrowth fixation, five components (7%) had stable fibrous ingrowth, and seven (10%) were unstable. Parallel radiodense lines were seen around the smooth portion of the stem in 93% of hips, but this finding appeared to have no clinical importance. Significant stress shielding of the proximal femur was seen in 16% of hips. Endosteal lysis of the distal femur occurred in 22% of hips, including large lesions in two patients who will require future revision surgery because of femoral diaphysis weakening. Femoral lysis was not associated with hip or thigh pain and was most common in young, male patients who had high activity levels.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for PubMedID 1431920

  • In vitro study of initial stability of a conical collared femoral component. journal of arthroplasty Fischer, K. J., Carter, D. R., Maloney, W. J. 1992; 7: 389-395

    Abstract

    This in vitro experimental study compared the initial stability of an uncemented conical collared femoral component to that of the same component with the collar removed. The two configurations examined simulated joint resultant forces encountered in single leg stance and stair climbing. For the simulated single leg stance loads, the data do not allow any inferences about relative component stability. With the exception of one collarless control, all micromotion for single leg stance loading was under 150 microns, measured approximately 1.5 cm below the resection line. For scaled stair-climbing loads, however, the conical collared component group was significantly more stable than the collarless control group in transverse (primarily rotational) micromotion. The overall average measured transverse motion for the collarless control group was more than 3.7 times greater than that of the conical collar group at scaled stair-climbing loads. The two conical collared components loaded to full peak stair-climbing load (2,100 N) exhibited micromotion under 160 microns. The results suggest that the conical collar may improve stability of an uncemented prosthesis under loads that include an out-of-plane (rotational) component.

    View details for PubMedID 1431921

  • Ingrowth of bone in failed fixation of porous-coated femoral components. journal of bone and joint surgery. American volume Jasty, M., Bragdon, C. R., Maloney, W. J., HAIRE, T., Harris, W. H. 1991; 73 (9): 1331-1337

    Abstract

    In five straight-stemmed, proximally porous-coated femoral components that were retrieved at revision arthroplasty from patients who had radiographic and clinical evidence of loosening, there was growth of bone into the porous coating. The components had been inserted during a primary arthroplasty in one woman and four men. The patients ranged in age from thirty-seven to sixty-seven years. Three patients were heavy, and all five were active. All patients had had an excellent early result from the initial arthroplasty; at the one-year follow-up, the mean Harris hip score had been 91 points. Pain in the hip developed in all of the patients, between one and three years after the index procedure. Initial radiographs had revealed excellent position and fixation of the prosthetic components, but the components then subsided between one and three and one-half years after the index procedure. All of the femoral components were found to be grossly loose at the revision operation. Nevertheless, all of the prosthetic components demonstrated growth of bone into 4 to 44 per cent (mean, 24 per cent) of the pore spaces available for ingrowth. Woven bone and fracture callus were found in the curettings from the proximal part of the femur. The findings in these five patients suggest that late failure of uncemented porous-surfaced femoral components can occur despite the presence of extensive ingrowth of bone. These failures may be the result of fatigue fractures of the trabeculae of the osseous ingrowth into the porous surfaces. Caution is warranted in the liberal use of these prosthetic components in heavy, active patients.

    View details for PubMedID 1918115

  • THE INITIATION OF FAILURE IN CEMENTED FEMORAL COMPONENTS OF HIP ARTHROPLASTIES JOURNAL OF BONE AND JOINT SURGERY-BRITISH VOLUME Jasty, M., Maloney, W. J., Bragdon, C. R., OCONNOR, D. O., HAIRE, T., Harris, W. H. 1991; 73 (4): 551-558

    Abstract

    We studied 16 femora retrieved at post-mortem from symptomless patients who had a satisfactory cemented total hip arthroplasty from two weeks to 17 years earlier, with the aim of delineating the initial mechanisms involved in loosening. Only one specimen showed radiographic evidence of loosening; the other 15 were stable to mechanical testing at 17.0 Nm of torque. In all 16 specimens, the cement-bone interface was intact with little fibrous tissue formation. By contrast, separation at the cement-prosthesis interface and fractures in the cement mantle were frequent. The most common early feature was debonding of the cement from the metal, seen at the proximal and distal ends of the prosthesis. Specimens which had been in place for longer also showed circumferential fractures in the cement, near the cement-metal interface, and radial fractures extending from this interface into the cement and sometimes to the bony interface. The most extensive cement fractures appeared to have started at or near sharp corners in the metal, or where the cement mantle was thin or incomplete. Fractures were also related to voids in the cement. The time relationship in this series suggested that long-term failure of the fixation of cemented femoral components was primarily mechanical, starting with debonding at the interface between the cement and the prosthesis, and continuing as slowly developing fractures in the cement mantle.

    View details for Web of Science ID A1991FZ05900005

    View details for PubMedID 2071634

  • INTRAOPERATIVE MEASUREMENT OF ROTATIONAL STABILITY OF FEMORAL COMPONENTS OF TOTAL HIP-ARTHROPLASTY CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Harris, W. H., MULROY, R. D., Maloney, W. J., Burke, D. W., Chandler, H. P., ZALENSKI, E. B. 1991: 119-126

    Abstract

    High out-of-plane forces acting on the hip joint can produce important rotational micromotion of the femoral component. This micromotion at the prosthesis interface may be detrimental to the stability of the implant. In cementless femoral implants this could prevent bone ingrowth, and in the cemented component this could cause generation of particulate debris, lysis, and loosening. The introduction of the torque wrench micrometer for assessment of intraoperative femoral component stability can quantify the initial stability of primary cementless femoral components and critically evaluate the stability (at either the initial or revision arthroplasty) of both cemented and cementless femoral components. It allows the surgeon to produce a known torque in the direction and magnitude of the out-of-plane forces that load the hip in vivo.

    View details for Web of Science ID A1991FK40100019

    View details for PubMedID 2019039

  • Incidence of heterotopic ossification after total hip replacement: effect of the type of fixation of the femoral component. journal of bone and joint surgery. American volume Maloney, W. J., Krushell, R. J., Jasty, M., Harris, W. H. 1991; 73 (2): 191-193

    Abstract

    The incidence and severity of heterotopic ossification after sixty-five consecutive primary uncemented total hip replacements were compared with those after seventy consecutive primary hybrid total hip replacements (consisting of an uncemented acetabular component and a cemented femoral component). All patients had had the arthroplasty because of osteoarthrosis. The sex distribution, prevalence of bilateral disease of the hip, and frequency of previous operations were similar in both groups. All of the operations were performed by one surgeon who used the same operative approach. Preoperative, immediate postoperative, and six-month follow-up radiographs were reviewed for all patients. For 90 per cent of the hips, radiographs that were made after a minimum follow-up of one year were also reviewed. In the group of patients who had an uncemented femoral component, there was a statistically significant increase in the frequency of heterotopic bone and in its severity. Either none or only class-I ectopic bone developed in 74 per cent of the hips in the hybrid group, compared with 40 per cent of the hips in the uncemented group (p less than 0.005). In contrast, class-III or IV heterotopic ossification was evident in 13 per cent of the hips in the uncemented group (p less than 0.005). None of the patients in the hybrid group needed reoperation for excision of ectopic bone, but four (6 per cent) of the patients in the uncemented group needed such a reoperation because of severe limitation of motion.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for PubMedID 1899666

  • SIMULTANEOUS CORRECTION OF PELVIC OBLIQUITY, FRONTAL PLANE, AND SAGITTAL PLANE DEFORMITIES IN NEUROMUSCULAR SCOLIOSIS USING A UNIT ROD WITH SEGMENTAL SUBLAMINAR WIRES - A PRELIMINARY-REPORT JOURNAL OF PEDIATRIC ORTHOPAEDICS Maloney, W. J., Rinsky, L. A., Gamble, J. G. 1990; 10 (6): 742-749

    Abstract

    Ten patients with neuromuscular scoliosis and pelvic obliquity had segmental spinal instrumentation using a unit Luque rod with sublaminar wires and fixation into the pelvis. Nine of the 10 patients also had anterior spinal fusion without instrumentation before the posterior procedure. Average preoperative pelvic obliquity was 42 degrees which was corrected to 6 degrees (82% correction). Average preoperative scoliosis was 92 degrees, which was corrected to 16 degrees (81% correction). Complications included a wound hematoma in one patient and a superficial wound dehiscence in another. There have been no pseudarthroses or hardware failures to date. Excellent correction of the pelvic obliquity and the spinal curve in neuromuscular scoliosis can be obtained with use of a unit rod and without use of anterior instrumentation.

    View details for Web of Science ID A1990EF61000007

    View details for PubMedID 2250058

  • BONE LYSIS IN WELL-FIXED CEMENTED FEMORAL COMPONENTS JOURNAL OF BONE AND JOINT SURGERY-BRITISH VOLUME Maloney, W. J., Jasty, M., Rosenberg, A., Harris, W. H. 1990; 72 (6): 966-970

    Abstract

    We have reviewed 25 cases of focal femoral osteolysis in radiographically stable, cemented femoral implants. In three hips retrieved at post-mortem from two patients, we have been able to make a detailed biomechanical and histological analysis. The interval between arthroplasty and the appearance of focal osteolysis on clinical radiographs ranged from 40 to 168 months, and in over 70% of the cases this did not appear until after five or more years. Few had significant pain and there was no relation to age, sex or original diagnosis. The most common site for osteolysis were Gruen zones 2 and 3 on the anteroposterior radiograph and zones 5 and 6 on the lateral radiograph. In 15 cases (60%), the area of osteolysis corresponded to either a defect in the cement mantle or an area of very thin cement. The rate of progression of these lesions was variable, but to date only one has progressed to gross loosening of the femoral component. The back-scatter scanning electron microscopic examination of serial sections and biomechanical testing of the post-mortem specimens demonstrated focal cement fracture around implants that were otherwise rigidly fixed. In eight cases from which tissue was available, histology showed a histiocytic reaction with evidence of particulate polymethylmethacrylate. We consider that this local fragmentation was the stimulus for local osteolysis in an otherwise stable cemented femoral component.

    View details for Web of Science ID A1990EG84200003

    View details for PubMedID 2246299

  • Comparison of a hybrid with an uncemented total hip replacement. A retrospective matched-pair study. journal of bone and joint surgery. American volume Maloney, W. J., Harris, W. H. 1990; 72 (9): 1349-1352

    Abstract

    The efficacy of a type of uncemented total hip replacement was compared with that of a hybrid total hip replacement in which an uncemented acetabular and a cemented femoral component were used. Twenty-five patients who had had a hybrid total hip replacement were matched, by age, weight, sex, and diagnosis, with twenty-five patients who had had an uncemented total hip replacement. All of the operations were done by one surgeon, who used the same operative approach and the same regimen of postoperative rehabilitation. All of the patients were followed for at least two years. The mean postoperative hip score was 96 points for the hybrid group and 84 points for the cementless group (p less than 0.02). Twenty-four (96 per cent) of the patients who had a hybrid prosthesis reported no or only slight pain postoperatively. In the uncemented group, of the six patients (24 per cent) who reported mild to severe pain, five had pain in the thigh, a limp occurred more frequently, five femoral components had migrated, and four hips needed reoperation. The results with the hybrid replacement that had a cemented femoral component were superior to those with the uncemented femoral component over the relatively brief period for which these patients were followed.

    View details for PubMedID 2229111

  • Histomorphological studies of the long-term skeletal responses to well fixed cemented femoral components. journal of bone and joint surgery. American volume Jasty, M., Maloney, W. J., Bragdon, C. R., HAIRE, T., Harris, W. H. 1990; 72 (8): 1220-1229

    Abstract

    Thirteen femora that were obtained at autopsy from patients in whom a cemented total hip replacement had been implanted from forty months to 17.5 years earlier were evaluated radiographically and morphologically. All of the patients had been functioning well, and only one of the prostheses showed radiographic evidence of loosening. Serial sections of the proximal portion of the femur that enclosed the femoral component of the prosthesis showed that the host bone was intimately and directly apposed to the cement, and fibrous tissue intervened only rarely. The bone-remodeling processes had created a dense shell of substantial new bone around the cement-mantle that resembled a new cortex, attached to the outer cortex by new trabecular struts. Evidence of ingrowth of bone from this dense shell of bone into the undulating surface of the cement was found in many areas. In the adjacent femoral cortex, there was substantial osteoporosis and cortical thinning. The cement-bone interface was intact and excellent throughout, despite the presence of fractures within the cement-mantle and de-bonding at the cement-prosthesis interface in some specimens. The cemented femoral components were well tolerated by the skeleton over a long period of use, and fibrous tissue had rarely formed at the femoral cement-bone interface of these well fixed and clinically successful prostheses. The cement-mantle was well supported by extensive medullary bone-remodeling and formation of a dense shell of new bone. The internal bone-remodeling helped to maintain the cemented femoral components over time and did not cause loosening of the prosthesis.

    View details for PubMedID 2398093

  • B-mode ultrasound scanning in the detection of proximal venous thrombosis after total hip replacement. journal of bone and joint surgery. American volume Woolson, S. T., MCCRORY, D. W., Walter, J. F., Maloney, W. J., Watt, J. M., CAHILL, P. D. 1990; 72 (7): 983-987

    Abstract

    A prospective study of the accuracy of real-time B-mode ultrasonography in detecting deep venous thrombosis in the femoral and popliteal veins of the lower extremity was conducted on a consecutive series of patients who had had a total hip replacement. Ascending venography was used as a diagnostic standard. One hundred and forty-three patients had ultrasound studies of both lower extremities and a venographic study of the operatively treated lower extremity at an average of 7.6 days postoperatively. The two tests were done within twenty-four hours of each other. Both ultrasonography and venography were done on 152 extremities. Two paired studies were excluded from the analysis of results because the ultrasound scans could not be interpreted. In 131 extremities, both diagnostic tests were negative for proximal thrombosis. Eight extremities had isolated thrombosis of a vein in the calf that was detected only by venography. In nineteen extremities, old or fresh thrombosis was diagnosed by venography. In four extremities, an old thrombosis of the superficial femoral vein was detected by both studies. In four of the extremities that had a new thrombus in the common femoral vein and in nine that had a new thrombus in the superficial femoral vein, abnormal findings on ultrasound scans correlated with those on venograms. There were two false-negative ultrasound scans and one false-negative venogram. The sensitivity, specificity, and accuracy of ultrasonography were 89, 100, and 99 per cent for the diagnosis of thrombosis of the proximal veins of the lower limb and 63, 100, and 93 per cent for the diagnosis of thrombosis when the entire venous system of the limb was included.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for PubMedID 2200790

  • Endosteal erosion in association with stable uncemented femoral components. journal of bone and joint surgery. American volume Maloney, W. J., Jasty, M., Harris, W. H., Galante, J. O., Callaghan, J. J. 1990; 72 (7): 1025-1034

    Abstract

    Sixteen cases of patients who had focal femoral osteolysis after total hip replacement without cement were identified. Fourteen of them were included in a retrospective review of 474 consecutive total hip replacements without cement in 441 patients who had been followed for at least two years. The criteria for inclusion in the study were focal osteolysis with a femoral component that appeared stable radiographically, and no subsidence or change of position of the implant. All but two patients were men and were quite active. The average age was forty-seven years (range, twenty to sixty-five years). Fourteen of the sixteen patients had an excellent clinical result (a Harris hip score of 90 points or more). In two patients, the hip replacement was revised and, in a third, a biopsy was done. In all three patients, the implant was found to be firmly fixed to the femur. In the two hips that were revised, extensive ingrowth of bone was demonstrated histologically, there was no evidence of infection, and a well defined fibrous membrane was found around the smooth portion of the stem. The histological specimens from these two hips contained focal aggregates of macrophages with particulate polyethylene and metallic debris. In the biopsy material from the hip that was not revised, a fine fibrous membrane lined a cystic cavity. Although the membrane contained an occasional macrophage, no foreign material was identified. Trabecular microfracture and osteoclastic resorption of bone were seen next to the fibrous lining. With one exception, osteolysis was not identified less than two years postoperatively. In most patients, osteolysis appeared after three years. This study showed that femoral osteolysis can occur around uncemented components.

    View details for PubMedID 2384501

  • THE INFLUENCE OF CONTINUOUS PASSIVE MOTION ON OUTCOME IN TOTAL KNEE ARTHROPLASTY CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Schurman, D. J., HANGEN, D., Goodman, S. B., Edworthy, S., Bloch, D. A. 1990: 162-168

    Abstract

    All primary condylar total knee replacement arthroplasties (TKAs) performed from 1977 to 1984 at the authors' institution were divided into two groups based on the use of continuous passive motion (CPM) in the immediate postoperative period. The control group consisted of 73 patients who were treated with 95 TKAs without postoperative CPM. The average age was 65.4 years. The study group consisted of 38 patients who had 51 TKAs in which CPM was used postoperatively. The mean patient age was 62.8 years. The most common diagnoses in both groups were osteoarthritis and rheumatoid arthritis. Range of motion (ROM) was recorded preoperatively, at discharge, at three months, one year, two years, and at the last follow-up visit. There were no statistically significant differences in the ROM between the two groups at any of these time periods. At two years, the mean flexion and extension in the study group were 99 degrees and -4 degrees, respectively, compared to 103 degrees and -5 degrees in the control group. The average hospital stay was 11.2 days in the study group, whereas it was 15.1 days in control group. In the control group, there was one superficial infection, no deep infections, and four pulmonary emboli compared with three superficial infections, two deep infections, and no pulmonary emboli in the study group. There was no difference in the transfusion requirements between the two groups. CPM is advocated by the authors to help achieve discharge ROM earlier, but the protocol has been changed to begin CPM on the second postoperative day to allow the wound to stabilize.

    View details for Web of Science ID A1990DM91300023

    View details for PubMedID 2364605

  • HYBRID TOTAL HIP-ARTHROPLASTY CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Harris, W. H., Maloney, W. J. 1989: 21-29

    Abstract

    One hundred twenty-six primary total hip arthroplasties composed of a hybrid cemented femoral component and a cementless acetabular component were followed for a minimum of two years (mean, 42 months). The average patient age was 63 years. The most common diagnosis was osteoarthritis (85 hips), although 13 of the cases were severe or total congenital dislocations. Overall, the results were excellent. The mean Harris hip score was 93. Postoperative pain was rated as none or slight in 94% of the cases. No patient had moderate or severe pain. No femoral or acetabular components were revised. Roentgenographically no femoral component was definitely or probably loose. One acetabular reconstruction component had migrated. The authors conclude that the selective use of cemented and cementless fixation by anatomic site in this hybrid form of hip arthroplasty provided excellent results for five and one-half years.

    View details for Web of Science ID A1989CC62800004

    View details for PubMedID 2582670

  • BIOMECHANICAL AND HISTOLOGIC INVESTIGATION OF CEMENTED TOTAL HIP ARTHROPLASTIES - A STUDY OF AUTOPSY-RETRIEVED FEMURS AFTER INVIVO CYCLING CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Jasty, M., Burke, D. W., OCONNOR, D. O., ZALENSKI, E. B., Bragdon, C., Harris, W. H. 1989: 129-140

    Abstract

    Eleven whole anatomic specimens of the femur were retrieved at autopsy from patients who previously had cemented total hip arthroplasty. Implant duration ranged from 0.5 to 210 months. Clinically and roentgenographically the implants were stable. A detailed biomechanical analysis evaluated bone strains and implant stability in both the single-limb stance and stair-climbing positions using a 100-pound spinal load. The stability offered by cement in these well-fixed prostheses was remarkable, with the maximum axial micromotion being 40 mu. This is a reflection of intimate osseointegration at the bone-cement interface with only rare intervening fibrous tissue. The strain gauge and photoelastic strain-coating studies revealed that marked stress shielding in the proximal medial femoral cortex persists long after a cemented femoral component is inserted. Even 17 years after surgery, the strain in the calcar region did not normalize.

    View details for Web of Science ID A1989CC62800015

    View details for PubMedID 2582664

  • External iliac arteriovenous fistula following total hip arthroplasty. A case report. journal of arthroplasty Woolson, S. T., Maloney, W. J., Tanner, J. B. 1989; 4 (3): 281-284

    Abstract

    An external iliac arteriovenous fistula developed 3 years after revision of the acetabular component of a total hip arthroplasty in a patient with rheumatoid arthritis. The mechanism of this complication, which also produced disseminated intravascular coagulopathy, was chronic erosion of the iliac artery from a large bolus of bone cement and/or the protrusio shell that were used to reconstruct a severe acetabular protrusio. Care must be taken to avoid intrapelvic intrusion of hardware or cement during acetabular reconstruction to avoid immediate and late injury to the iliac vessels.

    View details for PubMedID 2795035

  • CAST IMMOBILIZATION AFTER TOTAL ELBOW ARTHROPLASTY - A SAFE COST-EFFECTIVE METHOD OF INITIAL POSTOPERATIVE CARE CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Schurman, D. J. 1989: 117-122

    Abstract

    Seventeen nonconstrained total elbow replacements were inserted in 12 patients. One patient died prior to the one-year follow-up examination, and two others required revision in the immediate postoperative period. The remaining 14 primary total elbow arthroplasties in 11 patients were included in this study. There were eight women and three men with an average age of 58.1 years. The diagnosis was rheumatoid arthritis in 12 patients and posttraumatic arthritis and juvenile rheumatoid arthritis each in one patient. Postoperatively, patients were immobilized in a long arm cast. The mean hospital stay was 4.3 days. At four weeks, the patients were seen for cast removal. Instructions were given for range of motion (ROM) exercises and patients were encouraged to resume normal daily activities as tolerated. No formal physical therapy was prescribed. The average follow-up period was 32 months. Preoperatively, the mean elbow motions were flexion 124 degrees, extension 34 degrees, pronation 65 degrees, and supination 44 degrees. At the last follow-up examination, ROM had improved significantly in all directions except extension (flexion 141 degrees, extension 36 degrees, pronation 77 degrees, and supination 61 degrees). There was one ulnar nerve palsy that only partially resolved. Another patient's elbow had initially subluxed due to excessive shortening of the humerus; however, he had an excellent ROM and was asymptomatic at 31 months. There were no dislocations or wound healing problems. Cast immobilization provides an effective means of promoting soft-tissue healing, permitting early discharge from the hospital and simplifying the postoperative rehabilitation while achieving satisfactory ROM without formal physical therapy.

    View details for Web of Science ID A1989AJ74100018

    View details for PubMedID 2752611

  • DIGIT REPLANTATION APPLYING THE LEECH HIRUDO-MEDICINALIS CLINICAL ORTHOPAEDICS AND RELATED RESEARCH BRODY, G. A., Maloney, W. J., Hentz, V. R. 1989: 133-137

    Abstract

    Digits that were formerly assessed as nonreplantable may now be replanted with the help of the leech Hirudo medicinalis. The early experience with a series of patients who had relative contraindications for replantation is reported. In each case, venous repair was either marginal or technically impossible. Postoperative venous congestion developed following replantation and was treated with the application of medicinal leeches. Patient acceptance was high, and no infections developed. No patient required transfusion. The authors conclude that the use of medicinal leeches shows promise as a safe and effective method of providing temporary venous drainage in replanted digits.

    View details for Web of Science ID A1989AJ74100020

    View details for PubMedID 2752613

  • UNUNITED LOWER-LIMB FRACTURES WESTERN JOURNAL OF MEDICINE CSONGRADI, J. J., Maloney, W. J. 1989; 150 (6): 675-680

    Abstract

    Nonunion is a fairly common complication of fracture management, with an overall rate of about 3% for the skeleton as a whole and 9% for the tibia. High-energy injury fractures have a nonunion rate as high as 75%. Other factors that may lead to nonunion are inappropriate treatment, infection, and preexisting disease. The diagnosis of nonunion is based largely on clinical examination. Plain radiographs and tomograms, computed tomograms, and contrast imaging may be used to confirm nonhealing. Radionuclide imaging can help determine the presence of infection, an impaired blood supply, or impaired osteogenic activity at the fracture site. The treatment of ununited fractures is based on the principles of good fracture management: adequate immobilization, asepsis and soft tissue cover, osteoconduction (bone contact), osteoinduction (stimulation of bone growth), and metabolic well-being. New modalities for osteoinduction are promising adjuncts to standard treatment, the autogenous bone graft, but conclusive proof of efficacy in humans does not yet exist.

    View details for Web of Science ID A1989AB02300005

    View details for PubMedID 2665320

  • BENIGN METASTASIZING GIANT-CELL TUMOR OF BONE - REPORT OF 3 CASES AND REVIEW OF THE LITERATURE CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Maloney, W. J., Vaughan, L. M., Jones, H. H., Ross, J., Nagel, D. A. 1989: 208-215

    Abstract

    Three cases of benign giant-cell tumor (GCT) of bone with pulmonary metastasis are reported. In addition, 28 cases from the literature are reviewed. The patients were followed for a mean of 7.8 years (range from two to 29 years). The interval to metastasis ranged from zero to ten years with a mean of 3.2 years. Metastasis was not related to the number of previous operations. The local recurrence rate in the tumors that metastasized was 63%, suggesting that GCTs that metastasize may be an aggressive form of the tumor. The overall mortality rate was 16%. Persistent pulmonary disease does not carry a poor prognosis; surgical resection of accessible pulmonary nodules is recommended to provide histologic confirmation of the diagnosis, and prevent future complications secondary to local growth of the implants, as well as provide a potential cure. Chemotherapy has not improved survival and is associated with significant morbidity and is thus not recommended. Adjuvant radiation is recommended only for control of surgically unresectable lesions because of its potential association with sarcomatous degeneration in GCT.

    View details for Web of Science ID A1989U954000033

    View details for PubMedID 2656024

  • SUPERFICIAL FEMORAL PSEUDOANEURYSM AND ARTERIAL THROMBOEMBOLISM CAUSED BY AN OSTEOCHONDROMA JOURNAL OF PEDIATRIC ORTHOPAEDICS Woolson, S. T., Maloney, W. J., James, D. R. 1989; 9 (3): 335-337

    Abstract

    A 13-year-old boy with a symptomatic distal femoral osteochondroma was found to have a pseudoaneurysm of the superficial femoral artery caused by the tumor and occlusion of the anterior tibial artery due to arterial thromboembolism. Excision of the exostosis followed by saphenous vein grafting resulted in an excellent clinical recovery.

    View details for Web of Science ID A1989U380200014

    View details for PubMedID 2723054

  • Time-related improvement in the range of motion of the hip after total replacement. journal of bone and joint surgery. American volume Woolson, S. T., Maloney, W. J., Schurman, D. J. 1985; 67 (8): 1251-1254

    Abstract

    We studied the progression of improvement in the range of motion of the hip after total hip replacement as it was related to time postoperatively. One hundred and eight hip replacements performed by members of the Stanford University Division of Orthopaedic Surgery in ninety-two patients were included in the analysis. The hips had no major postoperative complications, and the range of motion was examined preoperatively; at six months, one year, and two years, postoperatively; and at a last follow-up examination at a minimum of 4.5 years. There was no statistically significant improvement in the flexion and abduction of the hip after the one-year follow-up visit, but adduction and internal and external rotation were improved significantly at the last follow-up (average, 7.5 years). Of multiple variables that were studied, including those related to the patient, to the size and design of the prosthesis, and to the orientation of the total hip components, only the preoperative range of motion of the hip and a history of previous surgical treatment were major determining factors in the postoperative improvement of the range of motion.

    View details for PubMedID 4055850

  • Methemoglobinemia in an infant. Arizona medicine Maloney, W. J., MACFARLANE, M. T., Rimsza, M. E. 1983; 40 (10): 700-702

    View details for PubMedID 6651539

Conference Proceedings


  • Age and Obesity Are Risk Factors for Adverse Events After Total Hip Arthroplasty Huddleston, J. I., Wang, Y., Uquillas, C., Herndon, J. H., Maloney, W. J. SPRINGER. 2012: 490-496

    Abstract

    Defining the epidemiology of adverse events after THA will aid in the development of strategies to enhance perioperative care.We identified (1) risk factors for adverse events in Medicare beneficiaries while hospitalized after THA and (2) trends in the rates of adverse events.Data were abstracted from medical records of 1809 Medicare beneficiaries who underwent THA from 2002 to 2007. We used the hierarchical generalized linear modeling approach to assess the odds of change in adverse events over time, the association of adverse events with outcomes, and the relationship of adverse events with patient characteristics by modeling the log-odds of adverse events as a function of demographic and clinical variables adjusted for year variable.The overall rate of adverse events was 5.8%; the 30-day mortality rate was 1.00%. Increased age, obesity, and year of procedure were risk factors for experiencing any adverse event. Annual rates of adverse events from 2002 to 2007 were 9.1%, 8.2%, 4.9%, 4.1%, 3.5%, and 3.0%, respectively. Experiencing any adverse event was associated with an increased length of stay and an increased chance of readmission but not with an increased chance of mortality. The annual rate of all adverse events decreased from 2002-2004 to 2005-2007 (odds ratio = 0.83; 95% confidence interval, 0.74-0.92).Older and obese patients should be counseled regarding their increased risk for the development of adverse events after THA. The cause of the decline in the rate of adverse events between two time periods is unclear and warrants further investigation to confirm and identify the cause.

    View details for DOI 10.1007/s11999-011-1967-y

    View details for Web of Science ID 000299056000022

    View details for PubMedID 21796477

  • Surgical treatment of pelvic osteolysis Maloney, W. J., Paprosky, W., Engh, C. A., Rubash, H. SPRINGER. 2001: 78-84

    Abstract

    Sixty-eight well-fixed acetabular cups with osteolysis in the pelvis and polyethylene wear were identified from a series of 124 reoperations for failed cementless sockets. The well-fixed sockets requiring reoperation were subdivided based on whether the liner was exchanged and lytic lesion grafted (Type I case) or the socket was removed and a complete revision was done (Type II case). In 40 patients (Type I cases), the polyethylene liner was exchanged and the osteolytic lesions were debrided. Allograft bone chips were packed into the lytic defect in 29 patients. In the remaining 11 patients, the lesions were debrided but not grafted. At final followup, all of the acetabular components were radiographically stable. No new osteolytic lesions were identified. Approximately 1/3 of the lesions had resolved completely regardless of whether they were grafted. The remaining 2/3 had decreased in size. In 28 patients (Type II cases), the socket was revised. Both strategies were successful in arresting the process of osteolysis during the course of this study (mean, 3.5 years). However, removal of well-fixed sockets was associated with significantly more bone loss.

    View details for Web of Science ID 000172493400010

    View details for PubMedID 11764374

  • Fixation, polyethylene wear, and pelvic osteolysis in primary total hip replacement Maloney, W. J., Galante, J. O., Anderson, M., Goldberg, V., Harris, W. H., Jacobs, J., Kraay, M., Lachiewicz, P., Rubash, H. E., Schutzer, S., Woolson, S. T. SPRINGER. 1999: 157-164

    Abstract

    A multicenter retrospective review was performed analyzing 1081 primary total hip replacements in 944 patients using the Harris Galante-I cementless acetabular component with screw fixation. All patients were followed up for a minimum of 5 years with a mean followup of 81 months. Linear polyethylene wear averaged 0.11 mm/year (range, 0-0.86 mm/year). Pelvic osteolysis was seen in 25 patients (2.3%). Migration of the acetabular component was seen in four hips. A subgroup of patients was reanalyzed at a minimum followup of 10 years. The mean linear polyethylene wear rate remained 0.11 mm/year. In this group, only one socket had migrated. There was an association between wear rate and age. On average, younger patients had higher wear rates. The risk for having pelvic osteolysis develop and the need for revision surgery also was age-related. Twenty-two percent of hip replacements (15 hips) in patients younger than 50 years of age at the time of their index operation had pelvic osteolysis develop. In contrast, for patients older than 50 years of age at the time of surgery only 7.8% (eight hips) had osteolysis of the pelvis develop. For patients older than 70 years of age at the time of primary total hip replacement, none had pelvic osteolysis develop.

    View details for Web of Science ID 000084102600017

    View details for PubMedID 10611870

  • Interleukin-4 inhibits granulocyte-macrophage colony-stimulating factor, interleukin-6, and tumor necrosis factor-alpha expression by human monocytes in response to polymethylmethacrylate particle challenge in vitro Trindade, M. C., Nakashima, Y., Lind, M., Sun, D. H., Goodman, S. B., Maloney, W. J., Schurman, D. J., Smith, R. L. JOHN WILEY & SONS INC. 1999: 797-802

    Abstract

    The outcome of total joint arthroplasty is determined by biological events at the bone-implant interface. Macrophages phagocytose implant or wear debris at the interface and release proinflammatory mediators such as interleukins 1 and 6, tumor necrosis factor-alpha, and prostaglandin E2. These mediators are thought to contribute to the resorption of periprosthetic bone. Previous studies of tissues harvested from the bone-implant interface of failed orthopaedic implants demonstrated a possible role for two other cytokines, granulocyte-macrophage colony-stimulating factor and interleukin-4. The present study examined the effects of in vitro challenge with polymethylmethacrylate particles on the expression of granulocyte-macrophage colony-stimulating factor by primary human monocytes/macrophages and the role of interleukin-4 in regulating this expression. The polymethylmethacrylate particles caused a dose-dependent release of granulocyte-macrophage colony-stimulating factor at 48 hours. This release was accompanied by increased expression of interleukins 6 and 1beta and tumor necrosis factor-alpha. Release of the lysosomal enzyme hexosaminidase also increased in response to the particles. Interleukin-4 inhibited the expression of granulocyte-macrophage colony-stimulating factor, interleukin-6, and tumor necrosis factor-alpha at 48 hours in a dose-dependent manner. The data presented in this study confirm the hypothesis that interleukin-4 downregulates particle-induced activation of macrophages, as demonstrated by the decreased release of proinflammatory mediators.

    View details for Web of Science ID 000084603300001

    View details for PubMedID 10632444

  • Osteoarthritis: Differential expression of matrix metalloproteinase-9 mRNA in nonfibrillated and fibrillated cartilage Tsuchiya, K., Maloney, W. J., Vu, T., Hoffman, A. R., Huie, P., Sibley, R., Schurman, D. J., Smith, R. L. WILEY-BLACKWELL. 1997: 94-100

    Abstract

    Expression of matrix metalloproteinase-9 mRNA in osteoarthritic and normal cartilage was analyzed using reverse transcription-polymerase chain reaction and in situ hybridization. Fifty-four osteoarthritic cartilage samples were obtained from 24 patients undergoing total knee arthroplasty. Sixteen normal cartilage samples were obtained from non-osteoarthritic knees of four autopsy cases. With normal cartilage, reverse transcription-polymerase chain reaction analysis for matrix metalloproteinase-9 mRNA showed that chondrocytes exhibited only a trace signal. In analysis of osteoarthritic cartilage, chondrocytes of moderately and severely fibrillated cartilage exhibited a 73-fold and 110-fold increase in matrix metalloproteinase-9 mRNA signal, respectively, relative to normal cartilage. Chondrocytes of nonfibrillated osteoarthritic cartilage exhibited a 6-fold increase (p < 0.02) in matrix metalloproteinase-9 mRNA signal relative to normal cartilage. Analysis of matrix metalloproteinase-9 mRNA expression in fresh-frozen sections of normal and osteoarthritic cartilage by in situ hybridization confirmed these results. This study showed that reverse transcription-polymerase chain reaction provides a sensitive index of mRNA levels in normal and osteoarthritic cartilage samples and suggests that increased expression of matrix metalloproteinase-9 precedes fibrillation of cartilage in the development of osteoarthritis.

    View details for Web of Science ID A1997WL95000013

    View details for PubMedID 9066532

  • Osteoblast adhesion to orthopaedic implant alloys: Effects of cell adhesion molecules and diamond-like carbon coating Kornu, R., Maloney, W. J., Kelly, M. A., Smith, R. L. JOHN WILEY & SONS INC. 1996: 871-877

    Abstract

    In total joint arthroplasty, long-term outcomes depend in part on the biocompatibility of implant alloys. This study analyzed effects of surface finish and diamond-like carbon coating on osteoblast cell adhesion to polished titanium-aluminum-vanadium and polished or grit-blasted cobalt-chromium-molybdenum alloys. Osteoblast binding was tested in the presence and absence of the cell adhesion proteins fibronectin, laminin, fibrinogen, and vitronectin and was quantified by measurement of DNA content. Although adherence occurred in serum-free medium, maximal osteoblast binding required serum and was similar for titanium and cobalt alloys at 2 and 12 hours. With the grit-blasted cobalt alloy, cell binding was reduced 48% (p < 0.05) by 24 hours. Coating the alloys with diamond-like carbon did not alter osteoblast adhesion, whereas fibronectin pretreatment increased cell binding 2.6-fold (p < 0.05). In contrast, fibrinogen, vitronectin, and laminin did not enhance cell adhesion. These results support the hypothesis that cell adhesion proteins can modify cell binding to orthopaedic alloys. Although osteoblast binding was not affected by the presence of diamond-like carbon, this coating substance may influence other longer term processes, such as bone formation, and deserves further study.

    View details for Web of Science ID A1996WC77400004

    View details for PubMedID 8982128

  • Periprosthetic osteolysis in total hip arthroplasty: The role of particulate wear debris Maloney, W. J., Smith, R. L. AMER ACAD ORTHOPAEDIC SURGEONS. 1996: 171-182

    View details for Web of Science ID A1996BH44V00020

    View details for PubMedID 8727736

  • AUTOPSY STUDIES OF THE BONE-CEMENT INTERFACE IN WELL-FIXED CEMENTED TOTAL HIP ARTHROPLASTIES Schmalzried, T. P., Maloney, W. J., Jasty, M., Kwong, L. M., Harris, W. H. CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS. 1993: 179-188

    Abstract

    Although knowledge of the clinical status of the implant is important, only instrumented mechanical testing of retrieved specimens provides quantitative assessment of implant fixation. This measurement allows placement of the implant along a continuum of loosening and is the foundation for the interpretation of subsequent findings. Analysis of implants that have been proven to be well fixed by instrumented testing reveals significant differences in the initial events in the loosening of femoral and acetabular components. Although radiolucencies were observed around all of these well-fixed femoral and acetabular components, the histology (and therefore the etiology) of the radiolucency is different and variable on the two sides of the articulation. The majority of femoral radiolucencies appear to be due to age and stress-related remodeling while particulate-induced bone resorption plays an important role in acetabular radiolucencies. A finding common to both sides of the articulation in these stable components, however, was intimate contact of bone with cement without any interposed soft tissue even after 17.5 years of service. Primary incompatibility and/or failure of the cement was not identified as a factor in initiating either femoral or acetabular component loosening. These studies document the long-term compatibility of bone with cement in bulk form. Improvements in cemented femoral component fixation should focus on stem design and cementing technique. Long-term acetabular component fixation can be improved by reduction or elimination of polyethylene wear and optimization of the bone-implant interface.

    View details for Web of Science ID A1993KW98700011

    View details for PubMedID 8478634

  • THE CEMENT INTERFACE - RETRIEVAL STUDIES Maloney, W. J., Schmalzried, T. P., Jasty, M., Kwong, L. M., Harris, W. H. RAVEN PRESS. 1993: 51-69

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