Bio

Bio


Dr. Cheung specializes in surgery related to the shoulder and elbow, including shoulder replacement surgery, complex revision surgery, fracture fixation, arthroscopy, rotator cuff repair, ligament reconstruction and repair. She has been in practice at Stanford since 2006. She is a Board-certified orthopedic surgeon, a Fellow of the American Academy of Orthopedic Surgery, Member of the prestigious American Shoulder Elbow Society, Member of the Association of Clinical Elbow and Shoulder Surgeons, Member of the Mayo Elbow Club, and a Board Member of the Northern California Orthopedic Society. She completed her Orthopaedic Surgery residency at Drexel University in Philadelphia, PA. She completed her Fellowship in Shoulder and Elbow Surgery at the Mayo Clinic, in Rochester, MN.

Voted "One of the Top 65 Orthopedic Surgeons" in the country nominated by other orthopedic surgeons in 2017 by Beckers Orthopedic Review.
Voted "One of the Top 70 Female Orthopedic Surgeons to Know" in 2011 by Beckers Orthopedic Review.

Her research has focused on clinical outcomes following revision of total shoulder replacements, revision of total elbow replacements, and treatment of complications following shoulder and elbow reconstruction procedures. Her publications include those in the Journal of Bone and Joint Surgery, Journal of Shoulder and Elbow Surgery, Journal of the American Academy of Orthopedic Surgeons, and Clinical Orthopedics and Related Research. She has presented her work and often lectures at regional and national orthpaedic surgery conferences, and has written numerous textbook chapters in the field of shoulder and elbow surgery.

She helps to train the next generation of orthopedic surgeons at Stanford.

Clinical Focus


  • Shoulder and Elbow Surgery
  • Orthopaedic Surgery
  • Shoulder replacement
  • Rotator cuff repair surgery
  • Arthroscopic surgery of shoulder and elbow
  • Shoulder / elbow /arm fracture surgery
  • Elbow replacement
  • Elbow reconstruction
  • Shoulder labral repair
  • Shoulder SLAP repair
  • Shoulder reconstruction

Academic Appointments


Honors & Awards


  • Founders Day Award, Primary Investigator for Residents, Stanford University Department of Orthopedic Surgery (2012, 2013)
  • Research Grant Award, American Shoulder Elbow Society (2010)
  • Nominee, American Orthopedic Association Residents Leadership Forum (2009)
  • Resident Research Grant, Primary Investigator, Orthopedic Research Education Foundation (2009)
  • First Place Award, Residents’ Bowl Philadelphia Orthopedic Society (2005)
  • Second Place Award, Drexel University Orthopedic Surgery Research Day (2005)
  • Third Place Award, Drexel University Orthopedic Surgery Research Day (2004)
  • Resident Research Award, Pennsylvania Orthopedic Society (2002)
  • Departmental Honors, UCLA (1996)
  • Alpha Lambda Delta National Honor Society, UCLA (1993-1996)
  • Phi Eta Sigma National Honor Society, UCLA (1993-1996)
  • Golden Key National Honor Society, UCLA (1992-1996)
  • Deans List, UCLA (1992-1993)

Boards, Advisory Committees, Professional Organizations


  • Faculty Shoulder and Elbow Service, Department of Orthopaedic Surgery, Stanford University (2006 - Present)
  • Achievement Award, American Academy of Orthopedic Surgeons (2015 - Present)
  • Member of Board of Directors, Northern California Western Orthopedic Association (2009 - 2011)
  • Diplomate, American Board of Orthopedic Surgery (2008 - Present)
  • Active Member, American Shoulder Elbow Society (2012 - Present)
  • Active Member, Association of Clinical Elbow and Shoulder Surgeons (2007 - Present)
  • Fellow, American Academy of Orthopedic Surgeons (2009 - Present)
  • Moderator, American Academy of Orthopedic Surgeons (2009 - Present)
  • Invited Faculty, International Congress of Joint Replacement, Shoulder (2014 - Present)
  • Invited Faculty, Orthopedic Learning Center, American Shoulder Elbow Society (2008 - Present)
  • Course Director, Stanford University Medical Scholars Program (2008 - Present)
  • Member, Mayo Elbow Club (2006 - Present)
  • Faculty/Lab Instructor, Mayo Clinic Annual Elbow Meeting (2006 - 2011)

Professional Education


  • Fellowship:Mayo Clinic Upper Extremity Fellowship (Shoulder and Elbow) (2006) MN
  • Residency:Drexel University College of Medicine Orthopaedic Surgery Program (2005) PA
  • Internship:Drexel University College of Medicine Orthopaedic Surgery Program (2001) PA
  • Medical Education:New York Medical College Registrar (2000) NY
  • Board Certification: Orthopaedic Surgery, American Board of Orthopaedic Surgery (2008)
  • BS, UCLA, Physiological Science

Research & Scholarship

Current Research and Scholarly Interests


Dr. Cheung specializes in surgery related to the shoulder and elbow, including fractures, joint replacements, rotator cuff repair, ligament repair, sports injuries and arthroscopic procedures. She is a Board-certified orthopedic surgeon, a Fellow of the American Academy of Orthopedic Surgery, Member of the prestigious American Shoulder Elbow Society, Member of the Association of Clinical Elbow and Shoulder Surgeons, Member of the Mayo Elbow Club, and a Board Member of the Northern California Orthopedic Society. She completed her Orthopaedic Surgery residency at Drexel University in Philadelphia, PA. She completed her Fellowship in Shoulder and Elbow Surgery at the world renowned Mayo Clinic, in Rochester, MN.

Her research has focused on clinical outcomes following revision of total shoulder replacements, revision of total elbow replacements, and treatment of complications following shoulder and elbow reconstruction procedures. Her publications include those in the Journal of Bone and Joint Surgery, Journal of Shoulder and Elbow Surgery, Journal of the American Academy of Orthopedic Surgeons, and Clinical Orthopedics and Related Research. She has presented her work and often lectures at regional and national orthpaedic surgery conferences, and has written numerous textbook chapters in the field of shoulder and elbow reconstruction. Her current research topics include localized bone mineral density in the shoulder after arthroplasty and 3-dimensional kinematic study of the shoulder girdle.

Teaching

2019-20 Courses


Publications

All Publications


  • Successful reversal of phrenic nerve blockade following washout of interscalene nerve block as demonstrated by ultrasonographic diaphragmatic excursion. Journal of clinical anesthesia Ngai, L. K., Ma, W., Costouros, J. G., Cheung, E. V., Horn, J., Tsui, B. C. 2019; 59: 46–48

    View details for DOI 10.1016/j.jclinane.2019.06.022

    View details for PubMedID 31212125

  • Clinical and radiographic comparison of a hybrid cage glenoid to a cemented polyethylene glenoid in anatomic total shoulder arthroplasty. Journal of shoulder and elbow surgery Friedman, R. J., Cheung, E., Grey, S. G., Flurin, P. H., Wright, T. W., Zuckerman, J. D., Roche, C. P. 2019

    Abstract

    This study reports the clinical and radiographic outcomes of a hybrid cage glenoid compared with an age-matched, sex-matched, and follow-up-matched cohort of cemented all-polyethylene peg glenoids in patients undergoing anatomic total shoulder arthroplasty with 2 years' minimum follow-up.We reviewed 632 primary anatomic total shoulder arthroplasty patients from an international multi-institutional database; 316 patients received hybrid cage glenoids and were matched for age, sex, and follow-up with 316 patients with cemented all-polyethylene peg glenoids. Each cohort received the same humeral component. Scoring was performed in all patients preoperatively and at latest follow-up using 5 outcome scoring metrics and 4 active range-of-motion measurements. A Student 2-tailed unpaired t test identified differences in outcomes; P < .05 denoted a significant difference.Cage glenoid patients had significantly lower rates of radiolucent glenoid lines (9.0% vs. 37.6%, P < .0001) and radiolucent humeral lines (3.0% vs. 9.1%, P = .0088) than all-polyethylene peg glenoid patients. In the cage glenoid cohort, 4 cases of aseptic glenoid loosening (1.3%) and 4 cases of articular surface dissociation (1.3%) occurred. In the all-polyethylene peg cohort, 12 cases of aseptic loosening (3.8%) occurred. Cage glenoid patients had a significantly lower revision rate than all-polyethylene peg glenoid patients (2.5% vs. 6.9%, P = .0088).At 50 months' mean follow-up, cage glenoids demonstrated equally good clinical outcomes to all-polyethylene peg glenoids. Cage glenoids had significantly fewer radiolucent lines around both the glenoid and humeral components and a lower revision rate. Longer-term follow-up is required to confirm these promising short-term results.

    View details for DOI 10.1016/j.jse.2019.04.049

    View details for PubMedID 31324502

  • Safety and Efficacy of Intraoperative Computer-Navigated Versus Non-Navigated Shoulder Arthroplasty at a Tertiary Referral ORTHOPEDIC CLINICS OF NORTH AMERICA Barrett, I., Ramakrishnan, A., Cheung, E. 2019; 50 (1): 95-+
  • Instability after reverse total shoulder arthroplasty JOURNAL OF SHOULDER AND ELBOW SURGERY Cheung, E. V., Sarkissian, E. J., Sox-Harris, A., Comer, G. C., Saleh, J. R., Diaz, R., Costouros, J. G. 2018; 27 (11): 1946–52
  • Instability after reverse total shoulder arthroplasty. Journal of shoulder and elbow surgery Cheung, E. V., Sarkissian, E. J., Sox-Harris, A., Comer, G. C., Saleh, J. R., Diaz, R., Costouros, J. G. 2018

    Abstract

    BACKGROUND: This study evaluated patients with and without a prosthetic dislocation after reverse total shoulder arthroplasty (RTSA) to identify risk factors for instability.METHODS: Dislocation and nondislocation cohorts were established for analysis in 119 patients who had undergone RTSA at our institution between 2011 and 2014. Preoperative history and parameters pertaining to RTSA design were evaluated for correlation with instability. A logistic regression model was used to analyze independent predictors.RESULTS: Eleven patients (9.2%) demonstrated instability in the early postoperative period. Dislocations occurred at an average of 8 weeks postoperatively (range, 3 days-5 months). The mean follow-up of all patients was 28 months (range, 6-106 months). Postoperative instability was associated with male gender, history of prior open shoulder surgery, and preoperative diagnoses of fracture sequelae, particularly proximal humeral or tuberosity nonunion. Absence of subscapularis repair was an independent predictor of instability. In addition, 5 of the 11 patients (45%) in the instability cohort sustained a second dislocation requiring another operation.CONCLUSIONS: Redislocation after revision surgery for the initial dislocation was an unexpected and alarming finding. Treatment for the initial dislocation event by placement of a thicker polyethylene insert was inadequate in 45% of patients of our cohort and required another revision with a larger glenosphere and thicker humeral inserts. Initial instability after RTSA must be carefully managed, especially in the revision and post-traumatic setting. Exchange to a thicker polyethylene insert only carries a higher risk of recurrent instability.

    View details for PubMedID 29934280

  • Are Age and Patient Gender Associated With Different Rates and Magnitudes of Clinical Improvement After Reverse Shoulder Arthroplasty? Clinical orthopaedics and related research Friedman, R. J., Cheung, E. V., Flurin, P., Wright, T., Simovitch, R. W., Bolch, C., Roche, C. P., Zuckerman, J. D. 2018; 476 (6): 1264–73

    Abstract

    BACKGROUND: An improved understanding of how gender differences and the natural aging process are associated with differences in clinical improvement in outcome metric scores and ROM measurements after reverse total shoulder arthroplasty (rTSA) may help physicians establish more accurate patient expectations for reducing postoperative pain and improving function.QUESTIONS/PURPOSES: (1) Is gender associated with differences in rTSA outcome scores like the Simple Shoulder Test (SST), the UCLA Shoulder score, the American Shoulder and Elbow Surgeons (ASES) Shoulder score, the Constant Shoulder score, and the Shoulder Pain and Disability Index (SPADI) and ROM? (2) Is age associated with differences in rTSA outcome scores and ROM? (3) What factors are associated with the combined interaction effect between age and gender? (4) At what time point during recovery does most clinical improvement occur, and when is full improvement reached?METHODS: We quantified and analyzed the outcomes of 660 patients (424 women and 236 men; average age, 72 ± 8 years; range, 43-95 years) with cuff tear arthropathy or osteoarthritis and rotator cuff tear who were treated with rTSA by 13 shoulder surgeons from a longitudinally maintained international database using a linear mixed effects statistical model to evaluate the relationship between clinical improvements and gender and patient age. We used five outcome scoring metrics and four ROM assessments to evaluate clinical outcome differences.RESULTS: When controlling for age, men had better SST scores (mean difference [MD] = 1.41 points [95% confidence interval {CI}, 1.07-1.75], p < 0.001), UCLA scores (MD = 1.76 [95% CI, 1.05-2.47], p < 0.001), Constant scores (MD = 6.70 [95% CI, 4.80-8.59], p < 0.001), ASES scores (MD = 7.58 [95% CI, 5.27-9.89], p < 0.001), SPADI scores (MD = -12.78 [95% CI, -16.28 to -9.28], p < 0.001), abduction (MD = 5.79° [95% CI, 2.74-8.84], p < 0.001), forward flexion (MD = 7.68° [95% CI, 4.15-11.20], p < 0.001), and passive external rotation (MD = 2.81° [95% CI, 0.81-4.8], p = 0.006). When controlling for gender, each 1-year increase in age was associated with an improved ASES score by 0.19 points (95% CI, 0.04-0.34, p = 0.011) and an improved SPADI score by -0.29 points (95% CI, -0.46 to 0.07, p = 0.020). However, each 1-year increase in age was associated with a mean decrease in active abduction by 0.26° (95% CI, -0.46 to 0.07, p = 0.007) and a mean decrease of forward flexion by 0.39° (95% CI, -0.61 to 0.16, p = 0.001). A combined interaction effect between age and gender was found only with active external rotation: in men, younger age was associated with less active external rotation and older age was associated with more active external rotation (beta0 [intercept] = 11.029, beta1 [slope for age variable] = 0.281, p = 0.009). Conversely, women achieved no difference in active external rotation after rTSA, regardless of age at the time of surgery (beta0 [intercept] = 34.135, beta1 [slope for age variable] = -0.069, p = 0.009). Finally, 80% of patients achieved full clinical improvement as defined by a plateau in their outcome metric score and 70% of patients achieved full clinical improvement as defined by a plateau in their ROM measurements by 12 months followup regardless of gender or patient age at the time of surgery with most improvement occurring in the first 6 months after rTSA.CONCLUSIONS: Gender and patient age at the time of surgery were associated with some differences in rTSA outcomes. Men had better outcome scores than did women, and older patients had better outcome scores but smaller improvements in function than did younger patients. These results demonstrate rTSA outcomes differ for men and women and for different patient ages at the time of surgery, knowledge of these differences, and also the timing of improvement plateaus in outcome metric scores and ROM measurements can both improve the effectiveness of patient counseling and better establish accurate patient expectations after rTSA.LEVEL OF EVIDENCE: Level III, therapeutic study.

    View details for PubMedID 29601384

  • Are Age and Patient Gender Associated With Different Rates and Magnitudes of Clinical Improvement After Reverse Shoulder Arthroplasty? CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Friedman, R. J., Cheung, E. V., Flurin, P., Wright, T., Simovitch, R. W., Bolch, C., Roche, C. P., Zuckerman, J. D. 2018; 476 (6): 1264–73
  • Functionally Graded, Bone- and Tendon-Like Polyurethane for Rotator Cuff Repair ADVANCED FUNCTIONAL MATERIALS Ker, D., Wang, D., Behn, A., Wang, E., Zhang, X., Zhou, B., Mercado-Pagan, A., Kim, S., Kleimeyer, J., Gharaibeh, B., Shanjani, Y., Nelson, D., Safran, M., Cheung, E., Campbell, P., Yang, Y. 2018; 28 (20)

    Abstract

    Critical considerations in engineering biomaterials for rotator cuff repair include bone-tendon-like mechanical properties to support physiological loading and biophysicochemical attributes that stabilize the repair site over the long-term. In this study, UV-crosslinkable polyurethane based on quadrol (Q), hexamethylene diisocyante (H), and methacrylic anhydride (M; QHM polymers), which are free of solvent, catalyst, and photoinitiator, is developed. Mechanical characterization studies demonstrate that QHM polymers possesses phototunable bone- and tendon-like tensile and compressive properties (12-74 MPa tensile strength, 0.6-2.7 GPa tensile modulus, 58-121 MPa compressive strength, and 1.5-3.0 GPa compressive modulus), including the capability to withstand 10 000 cycles of physiological tensile loading and reduce stress concentrations via stiffness gradients. Biophysicochemical studies demonstrate that QHM polymers have clinically favorable attributes vital to rotator cuff repair stability, including slow degradation profiles (5-30% mass loss after 8 weeks) with little-to-no cytotoxicity in vitro, exceptional suture retention ex vivo (2.79-3.56-fold less suture migration relative to a clinically available graft), and competent tensile properties (similar ultimate load but higher normalized tensile stiffness relative to a clinically available graft) as well as good biocompatibility for augmenting rat supraspinatus tendon repair in vivo. This work demonstrates functionally graded, bone-tendon-like biomaterials for interfacial tissue engineering.

    View details for PubMedID 29785178

  • Rate of Improvement in Clinical Outcomes with Anatomic and Reverse Total Shoulder Arthroplasty JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Simovitch, R. W., Friedman, R. J., Cheung, E. V., Flurin, P., Wright, T., Zuckerman, J. D., Roche, C. 2017; 99 (21): 1801–11

    Abstract

    This study quantifies the rate of improvement after anatomic and reverse total shoulder arthroplasty; a better understanding of the rate of improvement associated with each prosthesis type may better establish patient expectations for recovery.Prospectively collected data on 1,183 patients who underwent either anatomic total shoulder arthroplasty (n = 505) or reverse total shoulder arthroplasty (n = 678) were collected. The Simple Shoulder Test (SST), University of California at Los Angeles (UCLA) Shoulder, American Shoulder and Elbow Surgeons (ASES), Constant, and Shoulder Pain and Disability Index (SPADI) scores, along with range of motion, were recorded preoperatively and at routine postoperative time points. All included patients had a minimum follow-up of 2 years. The rate of improvement of these outcome measures was quantified for patients who underwent anatomic total shoulder arthroplasty and those who underwent reverse total shoulder arthroplasty to compare recovery over time.In this study, 3,587 visits by 1,183 patients were analyzed and several differences between prosthesis types were noted. Patients who underwent reverse total shoulder arthroplasty experienced larger improvements in the Constant score and active forward flexion, and patients who underwent anatomic total shoulder arthroplasty demonstrated better improvement in external rotation compared with patients who underwent reverse total shoulder arthroplasty at nearly all time points. By 72 months, improvement in flexion and abduction decreased for each prosthesis type, but in particular for reverse total shoulder arthroplasty. Full improvement was achieved by 24 months, although the majority of improvement was achieved in the first 6 months, with all 5 scoring metrics following a similar rate of improvement. The ASES, SPADI, and UCLA Shoulder scores closely mirrored each other in the magnitude of improvement, and the SST score demonstrated the largest improvement and the Constant score demonstrated the smallest improvement for both anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty.Both anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty reliably result in improved patient outcomes. However, anatomic total shoulder arthroplasty more reliably improves range of motion, particularly external rotation. Most improvement occurs by 6 months, with some additional improvement up to 2 years for both anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty. Although the indications for anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty are substantially different, in addition to the biomechanical differences, the improvement in outcome scores over time can be expected to be very similar. This study is helpful to patients and health-care providers to establish expectations regarding the rate of recovery after total shoulder arthroplasty.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

    View details for DOI 10.2106/JBJS.16.01387

    View details for Web of Science ID 000418580100009

    View details for PubMedID 29088034

  • Revision Total Elbow Arthroplasty JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Ramirez, M. A., Cheung, E. V., Murthi, A. M. 2017; 25 (8): E166–E174

    Abstract

    Despite recent technologic advances, total elbow arthroplasty has complication rates higher than that of total joint arthroplasty in other joints. With new antirheumatic treatments, the population receiving total elbow arthroplasty has shifted from patients with rheumatoid arthritis to those with posttraumatic arthritis, further compounding the high complication rate. The most common reasons for revision include infection, aseptic loosening, fracture, and component failure. Common mechanisms of total elbow arthroplasty failure include infection, aseptic loosening, fracture, component failure, and instability. Tension band fixation, allograft struts with cerclage wire, and/or plate and screw constructs can be used for fracture stabilization.

    View details for PubMedID 28737619

  • Treatment of Massive Irreparable Rotator Cuff Tears: A Cost-effectiveness Analysis ORTHOPEDICS Kang, J. R., Sin, A. T., Cheung, E. V. 2017; 40 (1): E65-E76

    Abstract

    Massive irreparable rotator cuff tears cause significant shoulder pain and dysfunction. Physical therapy (PT), arthroscopic debridement with biceps tenotomy (AD-BT), and hemiarthroplasty (HA) are treatments shown to reduce pain and improve quality of life. Reverse total shoulder arthroplasty (RTSA) is a newer surgical treatment option that may offer improved function. A cost-effectiveness analysis of these interventions has never been performed, and no head-to-head comparative effectiveness trials currently exist. A Markov decision analytic model was used to compare RTSA, HA, AD-BT, and PT as treatments for elderly patients with massive irreparable rotator cuff tears. Probabilities for complications, perioperative death, conversion procedures, and reoperations were derived from the literature, and costs were determined by average Medicare reimbursement rates from 2011. Reverse total shoulder arthroplasty yielded the most quality-adjusted life years (QALY) with 7.69, but greater benefits came at higher costs compared with other treatments. Sensitivity analyses showed that PT was the most cost-effective intervention at a health utility of 0.75 or greater (QALY 7.35). The health utility of RTSA was 0.72 or less (QALY 7.48) or RTSA probability of no complications was 0.83 or less (QALY 7.48 at cost of $23,830). Reverse total shoulder arthroplasty yielded benefits at a cost considered good value for money compared with other treatments. Reverse total shoulder arthroplasty is the preferred and most cost-effective treatment option for elderly patients with massive irreparable rotator cuff tears. For patients seeking pain relief without functional gains, AD-BT can be considered a cost-effective and cheaper alternative. The cost-effectiveness analysis approach can help guide clinical practice as well as the policies of health care systems and insurers. [Orthopedics. 2017; 40(1):e65-e76.].

    View details for DOI 10.3928/01477447-20160926-06

    View details for Web of Science ID 000397082400010

  • Hemiarthroplasty for Proximal Humerus Fractures TECHNIQUES IN SHOULDER AND ELBOW SURGERY Cheung, E. V. 2016; 17 (3): 110–15
  • Shoulder Arthroplasty: Key Steps to Improve Outcomes and Minimize Complications. Instructional course lectures Cheung, E. V., Diaz, R., Athwal, G. S., Sanchez-Sotelo, J., Sperling, J. W. 2016; 65: 109-126

    Abstract

    Advances in shoulder replacement surgery have allowed for the successful treatment of various shoulder conditions. As the elderly population increases and the surgical indications for shoulder replacement surgery continue to expand, the number of shoulder replacements performed annually will continue to increase. Accordingly, the number of complications also will be expected to increase. Successful shoulder replacement outcomes require surgeons to have a thorough understanding of the surgical indications, surgical technique, and potential complications of the procedure. By reviewing the key aspects of shoulder replacement surgery and focusing on the surgical technique and common complications for both anatomic and reverse total shoulder arthroplasty, surgeons can help improve outcomes and minimize complications.

    View details for PubMedID 27049185

  • Posterior Glenoid Wear in Total Shoulder Arthroplasty: Eccentric Anterior Reaming Is Superior to Posterior Augment CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Wang, T., Abrams, G. D., Behn, A. W., Lindsey, D., Giori, N., Cheung, E. V. 2015; 473 (12): 3928-3936

    Abstract

    Uncorrected glenoid retroversion during total shoulder arthroplasty may lead to an increased likelihood of glenoid prosthetic loosening. Augmented glenoid components seek to correct retroversion to address posterior glenoid bone loss, but few biomechanical studies have evaluated their performance.We compared the use of augmented glenoid components with eccentric reaming with standard glenoid components in a posterior glenoid wear model. The primary outcome for biomechanical stability in this model was assessed by (1) implant edge displacement in superior and inferior edge loading at intervals up to 100,000 cycles, with secondary outcomes including (2) implant edge load during superior and inferior translation at intervals up to 100,000 cycles, and (3) incidence of glenoid fracture during implant preparation and after cyclic loading.A 12°-posterior glenoid defect was created in 12 composite scapulae, and the specimens were divided in two equal groups. In the posterior augment group, glenoid version was corrected to 8° and an 8°-augmented polyethylene glenoid component was placed. In the eccentric reaming group, anterior glenoid reaming was performed to neutral version and a standard polyethylene glenoid component was placed. Specimens were cyclically loaded in the superoinferior direction to 100,000 cycles. Superior and inferior glenoid edge displacements were recorded.Surviving specimens in the posterior augment group showed greater displacement than the eccentric reaming group of superior (1.01 ± 0.02 [95% CI, 0.89-1.13] versus 0.83 ± 0.10 [95% CI, 0.72-0.94 mm]; mean difference, 0.18 mm; p = 0.025) and inferior markers (1.36 ± 0.05 [95% CI, 1.24-1.48] versus 1.20 ± 0.09 [95% CI, 1.09-1.32 mm]; mean difference, 0.16 mm; p = 0.038) during superior edge loading and greater displacement of the superior marker during inferior edge loading (1.44 ± 0.06 [95% CI, 1.28-1.59] versus 1.16 ± 0.11 [95% CI, 1.02-1.30 mm]; mean difference, 0.28 mm; p = 0.009) at 100,000 cycles. No difference was seen with the inferior marker during inferior edge loading (0.93 ± 0.15 [95% CI, 0.56-1.29] versus 0.78 ± 0.06 [95% CI, 0.70-0.85 mm]; mean difference, 0.15 mm; p = 0.079). No differences in implant edge load were seen during superior and inferior loading. There were no instances of glenoid vault fracture in either group during implant preparation; however, a greater number of specimens in the eccentric reaming group were able to achieve the final 100,000 time without catastrophic fracture than those in the posterior augment group.When addressing posterior glenoid wear in surrogate scapula models, use of angle-backed augmented glenoid components results in accelerated implant loosening compared with neutral-version glenoid after eccentric reaming, as shown by increased implant edge displacement at analogous times.Angle-backed components may introduce shear stress and potentially compromise stability. Additional in vitro and comparative long-term clinical followup studies are needed to further evaluate this component design.

    View details for DOI 10.1007/s11999-015-4482-8

    View details for PubMedID 26242283

  • Complications of Elbow Trauma HAND CLINICS Cheung, E. V., Sarkissian, E. J. 2015; 31 (4): 683-?

    Abstract

    The elbow is a highly congruent trochoginglymoid joint allowing motion in both flexion-extension and pronosupination across 3 articulations. Therefore, treatment of fractures of the elbow can be technically challenging to manage, even after initial surgery. The posttraumatic elbow is prone to complications such as stiffness associated with heterotopic ossification, instability or subluxation (posterolateral rotatory instability and varus posteromedial instability patterns), and wound complications. This article discusses the pathoanatomy, prevention, and treatment of these complications.

    View details for DOI 10.1016/j.hcl.2015.06.012

    View details for PubMedID 26498555

  • Determining Center of Rotation and Scapular Notching in Reverse Total Shoulder Arthroplasty: A Reliability Study TECHNIQUES IN SHOULDER AND ELBOW SURGERY Bragg, W., Niu, E., Harris, A. S., Nguyen, M., Cheung, E. 2015; 16 (2): 52–58
  • Patient adherence with postoperative restrictions after rotator cuff repair. Journal of shoulder and elbow surgery Silverio, L. M., Cheung, E. V. 2014; 23 (4): 508-513

    Abstract

    This study aimed to measure self-reported patient adherence to postoperative restrictions after rotator cuff repair, to evaluate correlations between adherence and functional outcome, and to identify possible indicators of poor adherence. We believed that poor adherence would correlate with poor functional outcome.Fifty consecutive patients undergoing repair for rotator cuff tears were included and instructed to wear an abduction brace for 6 weeks after surgery. Functional evaluations, including American Shoulder and Elbow Surgeons score, University of California-Los Angeles shoulder score, and Simple Shoulder Test, were made preoperatively and postoperatively. Patients commented on their adherence with a medical adherence measurement questionnaire.Average adherence was 88% (range, 59.2-100). There were no significant correlations between adherence and improvement in American Shoulder and Elbow Surgeons, University of California-Los Angeles, or Simple Shoulder Test scores after rotator cuff repair (P = .06245, .5891, and .7688). Of the patient demographics analyzed, only smoking status had a positive effect on adherence (P = .00432; coefficient, 9.867). All other demographics, including hand dominance, mechanism of injury, repair complexity, comorbidities, living status, employment status, and age, had no significant effect on self-measured adherence to postoperative restrictions (P = .7876, .5889, .6444, .4190, .0609, .4171, .5402).Patients' self-reported adherence did not correlate with shoulder outcome as measured on any of 3 functional outcome scores.

    View details for DOI 10.1016/j.jse.2013.09.018

    View details for PubMedID 24581418

  • MRI detection of forearm soft tissue injuries with radial head fractures. Hand (New York, N.Y.) McGinley, J. C., Gold, G., Cheung, E., Yao, J. 2014; 9 (1): 87-92

    Abstract

    This study aims to evaluate the incidence of forearm soft tissue abnormalities associated with radial head fracture severity based on the Mason classification system.Eighteen patients (age 18-45 years) were prospectively evaluated with elbow radiographs and magnetic resonance imaging (MRI) following longitudinal forearm trauma. MRI was performed within 10 days of the initial injury. Radiographs and MR images were evaluated in a blinded fashion by two musculoskeletal radiologists.Thirteen of 18 patients presented with Mason type I radial head fractures. In all patients with Mason type I fractures, the interosseous membrane (IOM) was intact. Two patients had Mason type II fractures with associated partial and compete tearing of the IOM and three patients had Mason type III fractures with complete tearing of the IOM. Edema was noted in the pronator quadratus in six of 13 type I injuries and seen in all type II and III injuries. No structural forearm soft tissue abnormalities were present in patients with Mason type I injuries. The presence of edema within the pronator quadratus correlated with distal forearm pain.The severity of radial head fracture correlates with longitudinal forearm injury evidenced by the presence of IOM tearing. The findings suggest patients with Mason type II or III fractures of the radial head should undergo further evaluation of the forearm for associated soft tissue injuries. Edema within the pronator quadratus was present following forearm trauma regardless of the severity of fracture and was related to symptomatic forearm pain.

    View details for DOI 10.1007/s11552-013-9561-2

    View details for PubMedID 24570643

  • Biomechanical evaluation of a coracoclavicular and acromioclacicular ligament reconstruction technique utilizing a single continuous intramedullary free tendon graft. Journal of shoulder and elbow surgery Abrams, G. D., McGarry, M. H., Jain, N. S., Freehill, M. T., Shin, S., Cheung, E. V., Lee, T. Q., Safran, M. R. 2013; 22 (7): 979-985

    Abstract

    Reconstruction of only the coracoclavicular (CC) ligaments may restore superior-inferior (S-I) but not anterior-posterior (A-P) stability of the acromioclavicular (AC) joint. Concomitant reconstruction of both the AC and CC ligaments may more reliably restore intact biomechanical characteristics of the AC joint.Ten matched pairs of shoulders were utilized. Five specimens underwent CC ligament reconstruction while an equal number underwent combined AC and CC ligament reconstruction utilizing an intramedullary tendon graft. Each of the reconstructions was compared with the intact contralateral control. Translational and load to failure characteristics were compared between groups.No difference was found in S-I translation between intact specimens and CC-only reconstructions (P = .20) nor between intact specimens and AC/CC reconstructions (P = .33) at 10 Newton (N) loads. Significant differences were noted in A-P translation between intact specimens and CC-only reconstructions (P < .001) but no difference in A-P translation between intact specimens and AC/CC reconstructions (P = .34).The A-P and S-I translational biomechanical characteristics of the AC joint were restored using the new technique described. Reconstruction of the CC ligaments only (versus AC/CC combined) led to significantly increased translational motion in the A-P plane as compared to intact control specimens.

    View details for DOI 10.1016/j.jse.2012.09.013

    View details for PubMedID 23313367

  • Response to letter to editor regarding "Risk factors for development of heterotopic ossification of the elbow after fracture fixation". Journal of shoulder and elbow surgery Abrams, G. D., Bellino, M. J., Cheung, E. V. 2013; 22 (7)

    View details for DOI 10.1016/j.jse.2013.03.011

    View details for PubMedID 23623207

  • Risk factors for development of heterotopic ossification of the elbow after fracture fixation JOURNAL OF SHOULDER AND ELBOW SURGERY Abrams, G. D., Bellino, M. J., Cheung, E. V. 2012; 21 (11): 1550-1554

    Abstract

    Postoperative heterotopic ossification (HO) about the elbow may occur after surgical fixation of fractures and can contribute to dysfunction. Factors associated with HO formation after surgical fixation of elbow trauma are not well understood.All patients who underwent surgery for elbow trauma at our institution from October 2001 through August 2010 were retrospectively reviewed. Patients with prior injury or deformity to the involved elbow were excluded. Demographic data; fracture type; surgical treatment; and presence, location, and size of HO were recorded. The Fisher exact test, χ(2) test, and multivariate logistic regression were used with an α value of .05 used for significance.A total of 159 patients were identified, with 89 (37 men and 52 women) meeting inclusion and exclusion criteria. The mean age was 54.4 years (range, 18-90 years), and the mean follow-up time was 180 days. Age, male gender, lateral collateral ligament repair, and dual-incision approach were not associated with increased ectopic bone formation. Distal humeral fractures were a significant predictor of heterotopic bone. In patients in whom HO ultimately developed, it was visible on radiographs obtained 2 weeks postoperatively in 86% of cases.This investigation found predictors for the development of HO after surgical fixation of intra-articular elbow fractures. Furthermore, HO went on to develop at the time of final follow-up in only 14% of patients without HO on radiographs obtained 2 weeks postoperatively. This may suggest that absence of HO on radiographs obtained 2 weeks postoperatively may predict a more favorable outcome.

    View details for DOI 10.1016/j.jse.2012.05.040

    View details for PubMedID 22947234

  • Arthroscopic Rotator Cuff Repair-Traditional Anchor Techniques OPERATIVE TECHNIQUES IN SPORTS MEDICINE Cheung, E. V., Safran, M. R. 2012; 20 (3): 213-219
  • Postoperative pain associated with orthopedic shoulder and elbow surgery: a prospective study JOURNAL OF SHOULDER AND ELBOW SURGERY Desai, V. N., Cheung, E. V. 2012; 21 (4): 441-450

    Abstract

    In the last 2 decades, extensive research in postoperative pain management has been undertaken to decrease morbidity. Orthopedic procedures tend to have increased pain compared with other procedures, but further research must be done to manage pain more efficiently. Postoperative pain morbidities and analgesic dependence continue to adversely affect health care.The study assessed the pain of 78 elbow and shoulder surgery patients preoperatively and postoperatively using the Short-Form McGill Pain Questionnaire (SF-MPQ). Preoperatively, each patient scored their preoperative pain (PP) and anticipated postoperative pain (APP). Postoperatively, they scored their 3-day (3dpp) and 6-week postoperative pain (6wpp). The pain intensities at these 4 intervals were then compared and analyzed using Pearson coefficients.APP and PP were strong predictors of postoperative pain. The average APP was higher than the average postoperative pain. The 6wpp was significantly lower than the 3dpp. Sex, chronicity, and type of surgery were not significant factors; however, the group aged 18 to 39 years had a significant correlation with postoperative pain.PP and APP were both independent predictors of increased postoperative pain. PP was also predictive of APP. Although, overall postoperative pain was lower than APP or PP due to pain management techniques, postoperative pain was still significantly higher in patients with increased APP or PP than their counterparts. Therefore, surgeons should factor patient's APP and PP to better manage their patient's postoperative pain to decrease comorbidities.

    View details for DOI 10.1016/j.jse.2011.09.021

    View details for PubMedID 22192767

  • Arthroscopic Rotator Cuff Repair - Traditional Anchor Techniques Operative Techniques in Sports Medicine Emilie Cheung, M., Marc Safran, MD 2012; 20 (3): 213-219
  • The "anconeus slide'': rotation flap for management of posterior wound complications about the elbow JOURNAL OF SHOULDER AND ELBOW SURGERY Fleager, K. E., Cheung, E. V. 2011; 20 (8): 1310-1316

    Abstract

    Wound dehiscence at the tip of the olecranon is not an uncommon complication associated with surgical approaches to the elbow that involve a posterior skin incision. Various flaps have been described in the treatment of such soft tissue defects, but have associated morbidity. The "anconeus slide" rotation flap has low morbidity and is technically simple. In this study, we review the surgical technique and describe our experience with the anconeus rotation flap in 20 consecutive patients.The records of 20 patients who underwent an anconeus rotation flap by a single surgeon, from September 2006 to March 2010 were reviewed. The procedure was performed in the setting of total elbow arthroplasty (TEA) in 12 patients, revision total elbow arthroplasty in 3 patients, wound complications in 4 patients, and for an acute open distal humerus fracture in 1 patient. Patients were evaluated postoperatively for wound healing, pain, and postoperative Mayo Elbow Performance Scores (MEPS).All 20 patients healed their surgical wounds completely. Postoperative MEPS scores averaged 79.3 (range, 50-100).The anconeus rotational flap is a technically simple, reliable, and safe option for treatment of posterior wound complications about the elbow, and in the setting of primary and revision TEA when wound healing is a clinical concern. We recommend its use in patients who have either compromised posterior soft tissue coverage, triceps insufficiency, or factors associated with the potential for compromised wound healing.

    View details for DOI 10.1016/j.jse.2010.11.031

    View details for PubMedID 21396832

  • Complications in Reverse Total Shoulder Arthroplasty JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Cheung, E., Willis, M., Walker, M., Clark, R., Frankle, M. A. 2011; 19 (7): 439-449

    Abstract

    Reverse total shoulder arthroplasty was initially used to manage complex shoulder problems. Indications have been expanded to include rotator cuff arthropathy, massive rotator cuff tear, failed shoulder arthroplasty, and fracture sequelae. Increased use of primary reverse total shoulder arthroplasty has led to reports of associated problems unique to the procedure. The most common complications include neurologic injury, periprosthetic fracture, hematoma, infection, scapular notching, dislocation, mechanical baseplate failure, and acromial fracture. Little information has been published regarding best practices for managing these complications.

    View details for PubMedID 21724923

  • Strategies in Biologic Augmentation of Rotator Cuff Repair: A Review CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Cheung, E. V., Silverio, L., Sperling, J. W. 2010; 468 (6): 1476-1484

    Abstract

    Degenerative rotator cuff tears are increasing with the aging population, and healing is not uniform after surgery. Rotator cuffs may show improved healing when biologic factors are added during surgery.We asked: (1) What cellular processes are involved in normal bone-to-tendon healing? (2) What approaches are being developed in tendon augmentation? (3) What approaches are being developed with the addition of growth factors?We reviewed research in relating to biologic augmentation and cellular processes involved in rotator cuff repair, focusing on animal models of rotator cuff repair and nonrandomized human trials.Regular bone-to-tendon healing forms a fibrous junction between tendon and bone that is distinct from the original bone-to-tendon junction. Tendon augmentation with cellular components serves as scaffolding for fibroblastic cells and a possible source of growth factors and fibroblastic cells. Extracellular matrices provide a scaffold for incoming fibroblastic cells, although current research does not conclusively confirm which if any of these scaffolds enhance repair owing in part to intermanufacturer variations and the limited human research. Growth factors and platelet-rich-plasma are established in other fields of research and may enhance repair but have not been rigorously tested.There is potential application of biologic augmentation to improve healing after rotator cuff repair. However, research in this field is still inconclusive and has not been sufficiently demonstrated to merit regular clinical use. Future human trials can elucidate the use of biologic augmentation in rotator cuff repairs.

    View details for DOI 10.1007/s11999-010-1323-7

    View details for PubMedID 20352390

  • Delivered growth factor therapy to improve healing after rotator cuff repair. Stem cells and cloning : advances and applications Cheung, E. V., Silverio, L., Yao, J. 2010; 3: 135-144

    Abstract

    Degenerative rotator cuff tears are a significant cause of shoulder pain in the aging population. Rotator cuff repair surgery may be more successful when growth factors are delivered to the repair site. This study was designed to determine the cellular processes involved in normal bone-to-tendon healing and the current approaches used for biologic augmentation of rotator cuff repair.This review focuses on animal studies of rotator cuff repair and early human trials.Regular bone-to-tendon healing forms a fibrous junction between tendon and bone that is markedly different from the original bone-to-tendon junction. Tendon augmentation with cellular components serves as scaffolding for endogenous fibroblastic cells and a possible source of growth factors and fibroblastic cells. Extracellular matrices provide a scaffold for incoming fibroblastic cells. However, research in extracellular matrices is not conclusive due to intermanufacturer variation and the lack of human subject research. Growth factors and platelet-rich plasma are established in other fields of research and show promise, but have not yet been rigorously tested in rotator cuff repair augmentation.Rotator cuff repair can benefit from biologic augmentation. However, research in this field is still young and has not yet demonstrated that the benefits in healing rates are significant enough to merit regular clinical use. Randomized controlled trials will elucidate the use of biologic augmentation in rotator cuff repairs.

    View details for DOI 10.2147/SCCAA.S7359

    View details for PubMedID 24198519

  • Delivered growth factor therapy to improve healing after rotator cuff repair STEM CELLS AND CLONING-ADVANCES AND APPLICATIONS Cheung, E. V., Silverio, L., Yao, J. 2010; 3: 135–44
  • External Fixation and Centralization Versus External Fixation and Ulnar Osteotomy: The Treatment of Radial Dysplasia Using the Resolved Total Angle of Deformity JOURNAL OF PEDIATRIC ORTHOPAEDICS McCarthy, J. J., Kozin, S. H., Tuohy, C., Cheung, E., Davidson, R. S., Noonan, K. 2009; 29 (7): 797-803

    Abstract

    The purpose of this study is to compare preliminary external fixation and centralization to ulnar osteotomy with external fixation for the treatment of radial dysplasia as measured by the resolved total angle (RTA) of deformity.This is a retrospective review of 11 patients (14 limbs) with radial dysplasia. The 3-dimensional deformity was measured by the RTA. Six patients (8 limbs, group 1) underwent correction of their angular deformity with preliminary external fixator distraction followed by centralization. Five patients (6 limbs, group 2) underwent ulnar osteotomy with external fixation. Mean age was 9 years, with a mean follow-up of 41 months.Initial RTA was 112 degrees for group 1, which improved to 38 degrees postoperatively, but worsened to 71 degrees at follow-up. In group 2 the initial RTA was 88 degrees, which improved to 50 degrees, with a worsening to 95 degrees at follow-up. The RTA was found to have high interrater and intrarater reliability.The RTA defines the maximum deformity in radial dysplasia and is a reliable measure. Using the RTA, we showed that preliminary external fixation and centralization are more effective than ulnar osteotomy with external fixation, but both have a high recurrence rate.III.

    View details for DOI 10.1097/BPO.0b013e3181b76855

    View details for Web of Science ID 000270499800025

    View details for PubMedID 20104165

  • Open distal clavicle resection : isolated or with adjunctive acromioplasty ACTA ORTHOPAEDICA BELGICA Cheung, E. V., Sperling, J. W., Zarkadas, P. C., Cofield, R. H. 2009; 75 (5): 581-587

    Abstract

    The purpose of this study was to assess outcomes following open distal clavicle resection for acromioclavicular joint arthritis or distal clavicle osteolysis, with and without associated acromioplasty. Patients with painful clinical findings limited to the acromioclavicular joint had isolated distal clavicle excision (23 shoulders). Patients with acromioclavicular joint abnormalities and rotator cuff tendinopathy also underwent acromioplasty (41 shoulders). At average follow-up of 8.3 years, pain scores improved from 4.7 (1 to 5 scale) to 2.3 (p < 0.001). Patient satisfaction improved from 1.8 (1 to 10 scale) to 8.3 (p < 0.001). Postoperatively the mean Simple Shoulder Test (SST) score was 10.9. The mean American Shoulder and Elbow Surgeons (ASES) Score was 88.3. There were no statistical differences in pain, satisfaction, motion, and shoulder scores between the two groups. Results of distal clavicle resection with or without acromioplasty are favourable with a low rate of complications and seldom is further surgery required.

    View details for Web of Science ID 000271598900002

    View details for PubMedID 19999867

  • Surgical Approaches to the Elbow JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Cheung, E. V., Steinmann, S. R. 2009; 17 (5): 325-333

    Abstract

    Surgical exposures for complex injuries about the elbow are technically demanding because of the high density of neurologic, vascular, and ligamentous elements around the elbow. The posterior approaches (ie, olecranon osteotomy, triceps-reflecting, triceps-splitting, triceps-reflecting anconeus pedicle flap, paratricipital) include techniques used to navigate the area around the triceps tendon and anconeus muscle. These approaches may be extended to gain access to the entire joint. The ulnar nerve, the anterior and posterior capsules, and the coronoid process are addressed by means of a medial approach. Lateral approaches are useful in addressing pathology at the radial head, capitellum, coronoid process, and anterior and posterior capsules. These approaches may be combined to address complex pathology in the setting of fracture fixation, arthroplasty, and capsular release.

    View details for PubMedID 19411644

  • High revision rate after total elbow arthroplasty with a linked semiconstrained device. Orthopedics Patil, N., Cheung, E. V., Mow, C. S. 2009; 32 (5): 321-?

    Abstract

    The clinical results of semiconstrained total elbow arthroplasty have been encouraging, especially in rheumatoid arthritis. This article presents medium-term clinical results, revision rates, and reasons for revision of a semiconstrained linked total elbow device (Solar Total Elbow; Stryker, Mahwah, New Jersey). We retrospectively reviewed 17 consecutive total elbow arthroplasty patients operated on between February 1994 and March 2001. Thirteen patients were available for clinical evaluation with an average follow-up of 8.4 years (range, 4-12.6 years). The presenting diagnosis was posttraumatic arthritis in 6 patients, rheumatoid arthritis in 6, and gouty arthritis in 1, with an average patient age of 63.4 years. The results were analyzed with regard to complications following the procedure, functional outcome using the Mayo Elbow Performance Score (MEPS), and radiological evaluation at latest follow-up. The mean MEPS improved from 32.1 to 65 at latest follow-up. Three patients had excellent results, 5 had good results, 1 had a fair result, and 4 had poor results. Seven patients required at least 1 revision surgery, including 2 with humeral component loosening, 2 with ulnar component loosening, and 2 with bushing failure. One patient required resection arthroplasty for deep periprosthetic infection. Three patients eventually sustained periprosthetic fractures. Five patients with rheumatoid arthritis and 2 patients with posttraumatic arthritis underwent revision surgery. Poor clinical outcomes and a high revision rate were noted in patients with posttraumatic arthritis. Further comparative studies with other semiconstrained devices are necessary to determine their clinical effectiveness in patients with rheumatoid arthritis.

    View details for PubMedID 19472967

  • Monteggia fracture-dislocation associated with proximal and distal radioulnar joint instability. A case report. journal of bone and joint surgery. American volume Cheung, E. V., Yao, J. 2009; 91 (4): 950-954

    View details for DOI 10.2106/JBJS.H.00269

    View details for PubMedID 19339581

  • Monteggia Fracture-Dislocation Associated with Proximal and Distal Radioulnar Joint Instability A Case Report JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Cheung, E. V., Yao, J. 2009; 91A (4): 950-954
  • Management of Proximal Humeral Nonunions and Malunions ORTHOPEDIC CLINICS OF NORTH AMERICA Cheung, E. V., Sperling, J. W. 2008; 39 (4): 475-482

    Abstract

    Surgical treatment of proximal humeral nonunions and malunions are technically challenging. Osteosynthesis with bone grafting for the treatment of nonunions is indicated in young, active patients with adequate bone stock in the proximal fragment and preservation of the glenohumeral articular surfaces. Corrective osteotomy may be a reasonable option for proximal humeral malunions in young patients without evidence of degenerative joint disease. Arthroplasty for proximal humerus nonunions and malunions has a guarded outcome because of limitations in shoulder motion, but pain relief is more consistently improved upon.

    View details for DOI 10.1016/j.ocl.2008.06.002

    View details for PubMedID 18803977

  • Locked plating for proximal humeral fractures CURRENT ORTHOPAEDIC PRACTICE Cheung, E. V. 2008; 19 (5): 535–37
  • Infection associated with hematoma formation after shoulder arthroplasty 17th Annual Meeting of the Musculoskeletal-Infection-Society Cheung, E. V., Sperling, J. W., Cofield, R. H. SPRINGER. 2008: 1363–67

    Abstract

    Hematoma formation requiring operative treatment after shoulder arthroplasty may be associated with higher patient morbidity. We therefore determined whether there was an association of hematoma formation requiring operative treatment with deep infection after shoulder arthroplasty. Between 1978 and 2006, we performed 4147 shoulder arthroplasties in 3643 patients. Of these, 12 shoulders (0.3%) underwent reoperation for hematoma formation. The mean time interval from arthroplasty to surgery for the hematoma was 7 days (range, 0.5-31 days). Among nine cases in which cultures were taken, six had positive cultures; the organisms included Propionibacterium acnes in three, Staphylococcus epidermidis in one, Streptococcus species in one, and Staphylococcus epidermidis with Peptostreptococcus in one. The minimum followup was 12 months (mean, 68 months; range, 12 to 294 months). Two of the 12 patients eventually underwent resection arthroplasty for deep infection. The Neer score was excellent in one, satisfactory in six, and unsatisfactory in five patients. The data suggest hematoma formation after shoulder arthroplasty is often accompanied by positive intraoperative cultures. The surgeon should be aware of the high rate of unsatisfactory results associated with this complication as well as the possibility of developing a deep infection requiring additional surgery.Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

    View details for DOI 10.1007/s11999-008-0226-3

    View details for PubMedID 18421541

  • Revision shoulder arthroplasty for glenoid component loosening JOURNAL OF SHOULDER AND ELBOW SURGERY Cheung, E. V., Sperling, J. W., Cofield, R. H. 2008; 17 (3): 371-375

    Abstract

    Although glenoid component loosening has been recognized as a common reason for failure after total shoulder arthroplasty, there are few studies on the outcome of revision surgery for this problem. The purpose of this study is to determine the outcome of patients who underwent revision for glenoid component loosening. Between 1976 and 2002, 68 shoulders in 66 patients underwent revision for glenoid loosening at our institution. Group I consisted of 33 shoulders that underwent placement of a new glenoid component, and group II consisted of 35 shoulders that had removal and bone grafting without glenoid reimplantation. Follow-up averaged 3.8 years for group I and 6.2 years for group II. There was significant overall improvement in pain from preoperatively to postoperatively in both groups (P = .0001). Pain relief occurred in 23 of 33 shoulders in group I and in 24 of 35 in group II (P = .9203). Regarding range of motion, there was no significant change from preoperatively to postoperatively (P > .05), except for active elevation in group I (P = .0387). Patient satisfaction occurred in 24 in group I and in 19 in group II (P = .1150). The rate of survival free of reoperation at 5 years was 91% (95% confidence interval, 81% to 100%) in group I and 78% (95% confidence interval, 63% to 96%) in group II (P = .3019). When the Neer result rating was applied, 9 shoulders in group I and 3 in group II had an excellent or satisfactory result (P = .0432). Twenty shoulders had late positive cultures, most commonly, Propionibacterium acnes. Glenoid revision surgery will often lead to pain relief and patient satisfaction. There is a slight clinical benefit to reimplanting a glenoid component whenever structurally possible. Positive cultures in revision surgery are common, with uncertain clinical significance.

    View details for DOI 10.1016/j.jse.2007.09.003

    View details for Web of Science ID 000255993000001

    View details for PubMedID 18282720

  • Complications of hinged external fixators of the elbow JOURNAL OF SHOULDER AND ELBOW SURGERY Cheung, E. V., O'Driscoll, S. W., Morrey, B. F. 2008; 17 (3): 447-453

    Abstract

    Despite the growing use of hinged external fixators of the elbow, there are no studies regarding the complications associated with their application. The purpose of this study is to report our experience with complications with this procedure. Between 1998 and 2005, we reviewed the records of 100 consecutive patients who were treated with hinged external fixators (including 433 pin sites). Complications specifically related to pin placement were recorded. There were 15 patients with minor complications (15%) involving 21 pins (4.8%) and 10 patients with major complications (10%) involving 29 pins (6.7%). Minor complications included local erythema and nonpurulent drainage lasting greater than 5 days in 9 patients (21 pins) and the need for skin release to decrease tension adjacent to pins in 6 patients (9 pins). Major complications included purulent pin site drainage in 1 patient (2 pins), fixator malalignment in 1, pin loosening in 4 (11 pins), and deep infection in 4. There were no fractures around the pin sites or nerve injuries associated with pin placement. With care, articulated external fixators can be used without a high incidence of major complications. Most of the complications were attributed to local pin site infection. Factors clinically associated with an increased risk of deep infection include a history of prior procedures in the post-traumatic elbow and the complexity of the operative technique.

    View details for DOI 10.1016/j.jse.2007.10.006

    View details for PubMedID 18313332

  • Chronic lateral elbow instability ORTHOPEDIC CLINICS OF NORTH AMERICA Cheung, E. V. 2008; 39 (2): 221-?

    Abstract

    Posterolateral rotatory instability of the elbow is the most common pattern of chronic lateral elbow instability. The primary lesion in posterolateral rotatory instability is injury or attenuation of the lateral ulnar collateral ligament. Posterolateral rotatory instability is diagnosed on the basis of careful history taking and specific physical examination techniques. Reconstruction of the lateral ulnar collateral ligament with repair of the surrounding soft tissue structures is recommended in patients who have symptoms of recurrent lateral instability. Open and arthroscopic reconstruction techniques have resulted in improvement of elbow function and satisfactory results in most patients, although mild limitation in terminal extension of the elbow is a common finding.

    View details for DOI 10.1016/j.ocl.2007.12.007

    View details for PubMedID 18374812

  • Treatment of periprosthetic humerus fractures associated with shoulder arthroplasty JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Steinmann, S. P., Cheung, E. V. 2008; 16 (4): 199-207

    Abstract

    The incidence of periprosthetic humerus fracture associated with shoulder arthroplasty is approximately 0.6% to 3%. Fractures of the humerus occur most often intraoperatively and are more common during total shoulder arthroplasty than hemiarthroplasty because of difficulties in gaining access to the glenoid. Osteopenia, advanced age, female sex, and rheumatoid arthritis are medical comorbid factors that may contribute to humerus fractures and associated delayed healing and poorer function. When the humeral prosthetic component is loose or the fracture line overlaps the majority of the length of the prosthesis, revision with a long-stem implant should be considered. When the fracture overlaps the tip of the prosthesis and extends distally, open reduction and internal fixation is recommended. When the fracture is completely distal to the prosthesis and satisfactory alignment at the fracture site can be maintained with a fracture brace, then a trial of nonsurgical treatment is recommended. The primary goals of treatment are fracture union and pain relief. Loss of glenohumeral motion has limited the successful treatment of this challenging problem.

    View details for Web of Science ID 000254661200003

    View details for PubMedID 18390482

  • Long-term outcome of anterior stabilization of the shoulder JOURNAL OF SHOULDER AND ELBOW SURGERY Cheung, E. V., Sperling, J. W., Hattrup, S. J., Cofield, R. H. 2008; 17 (2): 265-270

    Abstract

    This study reports long-term experience with anterior shoulder capsule stabilization by performing the Bankart repair when labral tearing was present with a laterally based T-capsule repair in both primary and revision surgery. Between 1979 and 1983, 34 patients underwent this procedure. They were categorized into a primary group of 22 patients and a revision group of 12 patients who had previous surgery to correct anterior shoulder instability. Patients completed our shoulder questionnaire and a Rowe questionnaire. The mean follow-up was 22 years (range, 11-27 years). No recurrent dislocations developed, 4 patients reported shoulder subluxation, and 11 felt apprehension. No patient had further anterior instability surgery. Two received total shoulder arthroplasty. Postoperative average pain was 1.6, average strength was 9.0, and average satisfaction was 8.3 (1-10 scales). Active elevation averaged 169 degrees, external rotation, 65 degrees; and internal rotation was to T12. There was an average of 10.2 "yes" responses on the Simple Shoulder Test. The total American Shoulder and Elbow Surgeons score averaged 84.3. Applying the Rowe rating, results were excellent in 16, good in 10, fair in 2, and poor in 4. Ratings were better in the primary surgery group (P = .0535). The use of this procedure for correction of shoulder instability can prevent recurrent dislocation, but some degree of instability remains. Clinically important arthritis seldom develops.

    View details for DOI 10.1016/j.jse.2007.06.005

    View details for Web of Science ID 000254363600014

    View details for PubMedID 18036836

  • Reimplantation of a total elbow prosthesis following resection arthroplasty for infection JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Cheung, E. V., Adams, R. A., Morrey, B. F. 2008; 90A (3): 589-594

    Abstract

    The best approach for treatment of infection after total elbow arthroplasty is not clearly defined. The purpose of this study was to report our experience with reimplantation of a total elbow prosthesis following a prior resection arthroplasty to treat infection.Between 1976 and 2003 at our institution, twenty-nine patients were treated with reimplantation of a total elbow prosthesis after a prior resection arthroplasty following a deep periprosthetic infection. Eleven of the twenty-nine patients had had at least one procedure performed on the elbow prior to the primary arthroplasty. The mean time interval between the resection arthroplasty and the reimplantation was 72.5 weeks. Patients were followed for an average of 7.4 years after the reimplantation. All patients were assessed clinically, and their medical records were retrospectively reviewed.The mean total Mayo Elbow Performance Score (MEPS) was 35.5 points (range, 15 to 60 points) before the reimplantation and 66.3 points (range, 20 to 100 points) postoperatively (p < 0.001). The most common infecting organism was Staphylococcus epidermidis, which was present in thirteen (45%) of the twenty-nine elbows, followed by methicillin-sensitive Staphylococcus aureus, which was present in seven (24%). The infection was not eradicated in eight elbows (28%).Reimplantation of a total elbow prosthesis after a prior resection arthroplasty is a reasonable option for the treatment of infection. Improvement in function can be expected in most patients. However, the chance of the infection recurring and requiring additional revision surgery is high.

    View details for DOI 10.2106/JBJS.F.00829

    View details for Web of Science ID 000253946500016

  • Reimplantation of a total elbow prosthesis following resection arthroplasty for infection. journal of bone and joint surgery. American volume Cheung, E. V., Adams, R. A., Morrey, B. F. 2008; 90 (3): 589-594

    Abstract

    The best approach for treatment of infection after total elbow arthroplasty is not clearly defined. The purpose of this study was to report our experience with reimplantation of a total elbow prosthesis following a prior resection arthroplasty to treat infection.Between 1976 and 2003 at our institution, twenty-nine patients were treated with reimplantation of a total elbow prosthesis after a prior resection arthroplasty following a deep periprosthetic infection. Eleven of the twenty-nine patients had had at least one procedure performed on the elbow prior to the primary arthroplasty. The mean time interval between the resection arthroplasty and the reimplantation was 72.5 weeks. Patients were followed for an average of 7.4 years after the reimplantation. All patients were assessed clinically, and their medical records were retrospectively reviewed.The mean total Mayo Elbow Performance Score (MEPS) was 35.5 points (range, 15 to 60 points) before the reimplantation and 66.3 points (range, 20 to 100 points) postoperatively (p < 0.001). The most common infecting organism was Staphylococcus epidermidis, which was present in thirteen (45%) of the twenty-nine elbows, followed by methicillin-sensitive Staphylococcus aureus, which was present in seven (24%). The infection was not eradicated in eight elbows (28%).Reimplantation of a total elbow prosthesis after a prior resection arthroplasty is a reasonable option for the treatment of infection. Improvement in function can be expected in most patients. However, the chance of the infection recurring and requiring additional revision surgery is high.

    View details for DOI 10.2106/JBJS.F.00829

    View details for PubMedID 18310709

  • Primary osteoarthritis of the elbow: Current treatment options JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Cheung, E. V., Adams, R., Morrey, B. F. 2008; 16 (2): 77-87

    Abstract

    In the elbow, as in other joints, primary osteoarthritis is characterized by pain, stiffness, mechanical symptoms, and weakness. But primary osteoarthritis of the elbow is unique in that there is relative preservation of articular cartilage and maintenance of joint space, with hypertrophic osteophyte formation and capsular contracture. Medical treatment and physical therapy may be initiated in the early stages of the disease process. Surgical treatment options include arthroscopic osteocapsular débridement, open ulnohumeral arthroplasty, distraction interposition arthroplasty, and total elbow arthroplasty. The potential for instability and loosening following total elbow arthroplasty in the setting of primary osteoarthritis limits the clinical application of this procedure. This patient population is generally younger than that recommended for total elbow arthroplasty, and their higher functional demands have limited the long-term success of this treatment option. The improvement in arthroscopic débridement techniques is perhaps the greatest advancement in the treatment of osteoarthritis of the elbow in recent years.

    View details for Web of Science ID 000252866100005

    View details for PubMedID 18252838

  • Spontaneous regression of postoperative ossification about the elbow: a case report. Journal of shoulder and elbow surgery Cheung, E. V., O'Driscoll, S. W. 2007; 16 (6): e15-6

    View details for PubMedID 17391990

  • Fractures of the capitellum HAND CLINICS Cheung, E. V. 2007; 23 (4): 481-?

    Abstract

    Fractures of the capitellum account for less than 1% of all elbow fractures. Because they may be difficult to visualize on plain radiographs, the clinician must have a high index of suspicion for their diagnosis. Anatomic alignment of these fractures is imperative; slight residual displacement may result in significant loss of elbow motion. Surgical management is described with open reduction internal fixation using variable pitch headless screws, precontoured plates, or bioabsorbable pins. The optimal method of fixation depends on the fracture pattern and degree of comminution. If the fracture fragments are too small for stable fixation, excision of the fragments is recommended. Osteonecrosis, as well as, end-stage arthrosis requiring total elbow arthroplasty, has been reported as a rare, but potential, complication.

    View details for DOI 10.1016/j.hcl.2007.08.001

    View details for PubMedID 18054675

  • Polyethylene insert exchange for wear after toad shoulder arthroplasty JOURNAL OF SHOULDER AND ELBOW SURGERY Cheung, E. V., Sperling, J. W., Cofield, R. H. 2007; 16 (5): 574-578

    Abstract

    Virtually no information is available in the literature to guide clinical decision-making in regard to modular polyethylene exchange with metal-backed glenoid components in total shoulder arthroplasty for the indication of polyethylene wear. This level IV study reports our experience with exchange of the modular polyethylene glenoid component during revision total shoulder arthroplasty. We retrospectively identified 12 shoulders in 11 patients who underwent exchange of the modular polyethylene glenoid component during revision arthroplasty. The primary reason for revision arthroplasty with polyethylene exchange was wear-through or displacement of the polyethylene portion of the glenoid component, but rotator cuff tearing and instability often coexisted. The average follow-up from time of revision to latest evaluation or repeat revision arthroplasty was 68 months. Preoperative pain was a mean of 4.5 (range, 4-5), and postoperative pain was a mean of 2.6 (range, 1-5). Preoperative average active forward elevation was 93 degrees, and external rotation was 51 degrees. Postoperative active forward elevation was 89 degrees, and external rotation was 64 degrees. Average patient satisfaction was rated as the same. According to the modified Neer rating system, 4 shoulders (33%) had a satisfactory result, and 8 (62%) had an unsatisfactory result. Polyethylene exchange of glenoid component after total shoulder arthroplasty can be an effective treatment option in patients who do not have coexistent rotator cuff tear or instability. For most, instability, rotator cuff tear, and glenoid wear occur together, and this is a challenging problem to treat successfully.

    View details for DOI 10.1016/j.jse.2006.12.009

    View details for Web of Science ID 000250151500013

    View details for PubMedID 17531512

  • Reimplantation of a glenoid component following component removal and allogenic bone-grafting JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Cheung, E. V., Sperling, J. W., Cofield, R. H. 2007; 89A (8): 1777-1783

    Abstract

    Glenoid component loosening has been a leading cause of failure of total shoulder arthroplasty. In the present study, we evaluated the outcome of reimplantation of a new glenoid component following removal of the previous glenoid component and placement of an allograft in order to determine the results, risk factors for an unsatisfactory outcome, and rate of failure associated with this procedure.We reviewed the data on seven shoulders in seven patients. At the time of glenoid component reimplantation, two shoulders received a cemented all-polyethylene glenoid component, three received a bone-ingrowth metal-backed component with columns and screws, and two received a bone-ingrowth metal-backed component with columns and screws augmented with bone cement. The average duration of follow-up was seventy-nine months. At the time of the latest follow-up, all patients were evaluated clinically and radiographically, patient satisfaction was assessed, and the result was graded according to a modified Neer rating system.Two patients had positive growth of Propionibacterium acnes on culture of intraoperative specimens obtained at the time of revision surgery and had continuing pain, and both underwent repeat revision. The remaining five patients expressed satisfaction with the procedure and stated that they felt better following surgery. The mean preoperative pain score for these five patients (on a scale from 1 to 5) was 4.6, and the mean postoperative pain score was 2.4 (p = 0.0042). Range of motion, however, did not improve. The Neer rating of the result (determined for the five patients who did not undergo repeat revision) was excellent for one patient, satisfactory for one, and unsatisfactory (because of limitation of motion) for three.Reimplantation of a glenoid component into a previously grafted bed can provide pain relief for most patients, but motion cannot be reliably improved.

    View details for DOI 10.2106/JBJS.F.00711

    View details for Web of Science ID 000248546300016

  • Total elbow prosthesis loosening caused by ulnar component pistoning JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Cheung, E. V., O'Driscoll, S. W. 2007; 89A (6): 1269-1274

    Abstract

    Linked semiconstrained total elbow prostheses have been used successfully but may be at higher risk for implant loosening than unlinked implants are. The purpose of the present report was to describe a previously unreported and potentially preventable cause of mechanical loosening of the ulnar component of a linked total elbow prosthesis.A series of ten patients who had painful pistoning of the polymethylmethacrylate-coated ulnar component of a Coonrad-Morrey linked total elbow prosthesis were evaluated clinically and radiographically.All ten patients complained of elbow pain, and eight had a distinct sensation of the ulnar component moving within the ulna. Six patients either complained of squeaking within the elbow or could demonstrate squeaking on examination. Four patients had a complete radiolucent line around the ulnar component or the cement mantle, and six had an incomplete line around the ulnar component. Six patients had a radiolucent gap between the cement and the tip of the ulnar prosthesis. Two patients had proximal migration of the ulnar component within the cement mantle on lateral flexion radiographs. Three patients had anterior impingement, such as between the anterior flange of the humeral implant and a prominent coronoid process, on lateral flexion radiographs. At the time of revision arthroplasty, all ten patients were found to have a loose ulnar component, which was successfully revised with or without impaction grafting. At the time of the most recent follow-up, nine of the ten ulnar components were intact and stable. Three patients required an additional reoperation: one required triceps repair, one required revision of a loose humeral component, and one required a revision total elbow arthroplasty.Pistoning of the ulnar component in the cement mantle leading to failure by means of a pullout mechanism can occur in association with the Coonrad-Morrey total elbow prosthesis with a polymethylmethacrylate-precoated ulnar component. To prevent this problem following any total elbow arthroplasty, the surgeon should check for anterior impingement intraoperatively by ensuring that there is no contact between the anterior flange and a prominent coronoid process or the cement and that no distraction of the trial ulnar component from the ulna occurs with passive elbow flexion. This condition also can be avoided by ensuring that the ulnar component is not inserted too far distally. This mechanism of failure should be considered when future total elbow arthroplasty implants are designed.Therapeutic Level IV.

    View details for Web of Science ID 000247085800015

  • Spondylolysis and spondylolisthesis in children and adolescents: II. Surgical management JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Cheung, E. V., Herman, M. J., Cavalier, R., Pizzutillo, P. D. 2006; 14 (8): 488-498

    Abstract

    Surgical management is indicated for children and adolescents with spondylolysis and low-grade spondylolisthesis (< or =50% slip) who fail to respond to nonsurgical measures. In situ posterolateral L5 to S1 fusion is the best option for those with a low-grade slip secondary to L5 pars defects or dysplastic spondylolisthesis at the lumbosacral junction. Pars repair is reserved for patients with symptomatic spondylolysis and low-grade, mobile spondylolisthesis with pars defects cephalad to L5 and for those with multiple-level defects. Screw repair of the pars defect, wiring transverse process to spinous process, and pedicle screw-laminar hook fixation are surgical options. The ideal surgical management of high-grade spondylolisthesis (>50% slip) is controversial. Spinal fusion has been indicated for children and adolescents with high-grade spondylolisthesis regardless of symptoms. In situ L4 to S1 fusion with cast immobilization is safe and effective for alleviating back pain and neurologic symptoms. Instrumented reduction and fusion techniques permit improved correction of sagittal spinal imbalance and more rapid rehabilitation but are associated with a higher risk of iatrogenic nerve root injuries than in situ techniques. Wide decompression of nerve roots combined with instrumented partial reduction may diminish the risk of neurologic complications. Pseudarthrosis and neurologic injury presenting as L5 radiculopathy and sacral root dysfunction are the most common complications associated with surgical management of high-grade spondylolisthesis.

    View details for Web of Science ID 000239707500006

    View details for PubMedID 16885480

  • Spondylolysis and spondylolisthesis in children and adolescents: I. Diagnosis, natural history, and nonsurgical management JOURNAL OF THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS Cavalier, R., Herman, M. J., Cheung, E. V., Pizzutillo, P. D. 2006; 14 (7): 417-424

    Abstract

    Spondylolysis and spondylolisthesis are often diagnosed in children presenting with low back pain. Spondylolysis refers to a defect of the vertebral pars interarticularis. Spondylolisthesis is the forward translation of one vertebral segment over the one beneath it. Isthmic spondylolysis, isthmic spondylolisthesis, and stress reactions involving the pars interarticularis are the most common forms seen in children. Typical presentation is characterized by a history of activity-related low back pain and the presence of painful spinal mobility and hamstring tightness without radiculopathy. Plain radiography, computed tomography, and single-photon emission computed tomography are useful for establishing the diagnosis. Symptomatic stress reactions of the pars interarticularis or adjacent vertebral structures are best treated with immobilization of the spine and activity restriction. Spondylolysis often responds to brief periods of activity restriction, immobilization, and physiotherapy. Low-grade spondylolisthesis (< or =50% translation) is treated similarly. The less common dysplastic spondylolisthesis with intact posterior elements requires greater caution. Symptomatic high-grade spondylolisthesis (>50% translation) responds much less reliably to nonsurgical treatment. The growing child may need to be followed clinically and radiographically through skeletal maturity. When pain persists despite nonsurgical interventions, when progressive vertebral displacement increases, or in the presence of progressive neurologic deficits, surgical intervention is appropriate.

    View details for Web of Science ID 000239178100004

    View details for PubMedID 16822889

  • Immediate range of motion after distal biceps tendon repair JOURNAL OF SHOULDER AND ELBOW SURGERY Cheung, E. V., Lazarus, M., Taranta, M. 2005; 14 (5): 516-518

    Abstract

    The purpose of this study was to determine the effect of immediate postoperative motion on strength and elbow motion after repair of a distal biceps tendon rupture. We conducted a retrospective review of 13 patients who had repairs of a unilateral distal biceps tendon rupture with a minimum follow-up of 2 years. The repairs were performed via a 2-incision technique. The elbows were placed into hinged braces immediately postoperatively, and range of motion was limited to 60 degrees of flexion to full limitation on flexion on the first postoperative day. Elbow extension block was decreased to 40 degrees at 2 weeks, 20 degrees at 4 weeks, and full extension at 6 weeks postoperatively. Elbow range of motion, biceps strength, and Disabilities of the Arm, Shoulder, and Hand scores were recorded at follow-up. There was a mean loss of 5.8 degrees of full extension when compared with the uninjured side, with no loss of flexion. There was a mean loss of 3.5 degrees of pronation and 8.1 degrees of supination. Flexion strength was 91.4% and supination strength was 89.4% of that of the uninjured side. The mean Disabilities of the Arm, Shoulder, and Hand score was 42.8. We conclude that immediate postoperative range of motion after repair of the distal biceps tendon leads to early gain of extension and has no deleterious effect on healing or strength.

    View details for DOI 10.1016/j.jse.2004.12.003

    View details for Web of Science ID 000232611500011

    View details for PubMedID 16194744

  • An undescribed cause of patellar tendon rupture. American journal of orthopedics (Belle Mead, N.J.) Hosalkar, H. S., Cheung-Moore, E., Atanda, A., Ogilvie, C., Lackman, R. D. 2005; 34 (7): 333-336

    Abstract

    We present a rare case of a myxoid-feature lipoma that arose in the patella fat pad and caused patellar tendon rupture.

    View details for PubMedID 16130351

  • Administration of the non-steroidal anti-inflammatory drug ibuprofen increases macrophage concentrations but reduces necrosis during modified muscle use INFLAMMATION RESEARCH Cheung, E. V., Tidball, J. G. 2003; 52 (4): 170-176

    Abstract

    To test the hypothesis that ibuprofen administration during modified muscle use reduces muscle necrosis and invasion by select myeloid cell populations.Rats were subjected to hindlimb unloading for 10 days, after which they experienced muscle reloading by normal weight-bearing to induce muscle inflammation and necrosis. Some animals received ibuprofen by intraperitoneal injection 8 h prior to the onset of muscle reloading, and then again at 8 and 16 h following the onset of reloading. Other animals received buffer injection at 8 h prior to reloading and then ibuprofen at 8 and 16 h following the onset of reloading. Control animals received buffer only at each time point. Quantitative immunohistochemical analysis was used to assess the presence of necrotic muscle fibers, total inflammatory infiltrate, neutrophils, ED1+ macrophages and ED2+ macrophages at 24 h following the onset of reloading.Administration of ibuprofen beginning 8 h prior to reloading caused significant reduction in the concentration of necrotic fibers, but increased the concentration of inflammatory cells in muscle. The increase in inflammatory cells was attributable to a 2.6-fold increase in the concentration of ED2+ macrophages. Animals treated with ibuprofen 8 h following the onset of reloading showed no decrease in muscle necrosis or increase in ED2+ macrophage concentrations.Administration of ibuprofen prior to increased muscle loading reduces muscle damage, but increases the concentration of macrophages that express the ED2 antigen. The increase in ED2+ macrophage concentration and decrease in necrosis may be mechanistically related because ED2+ macrophages have been associated with muscle regeneration and repair.

    View details for Web of Science ID 000182738200005

    View details for PubMedID 12755383