Hip Dysplasia Research

Developmental dysplasia of the hip (DDH, or hip dysplasia, is a developmental condition that occurs during the growth of the hip joint, over the first 1-2 decades of life. Hip dysplasia describes a shallow acetabulum or hip socket that is insufficiently deep to adequately cover the femoral head. This insufficient coverage creates abnormal hip loading mechanics where the bone and cartilage at the edge of the acetabulum see very high loading forces during weight-bearing activities such as standing and walking. If hip dysplasia is left untreated, these high loads at the rim of the socket cause the hip’s cartilage and labrum to break down, causing pain, decreased function, and eventually hip osteoarthritis.

Hip dysplasia is the most common pediatric hip condition – about 1 in 6 newborns will have hip instability and about 3 in 1,000 will require surgery for hip dysplasia. Hip dysplasia can result in pain and dysfunction starting in childhood through young adulthood, and is the leading cause of early-onset hip osteoarthritis before the age of 60 years. The poor prognosis of hip dysplasia warrants careful attention towards early identification and intervention in these hips with anatomical risk factors for mechanical misbehavior. Our research is focused on the proper screening, diagnosis, treatment, and prevention of hip dysplasia to provide the best patient care and improve the quality of life for those affected.

A Multi-Center Cohort Investigating Surgical Outcomes and Predictors of Treatment for Hip Disease

What is the purpose of this research?

This multi-center research prospective multicenter cohort study is a collaborative project between Stanford University and other leading hip preservation academic institutions across the United States. The goal is to longitudinally collect and analyze data from patients undergoing hip preservation surgery across multiple research institutions nationally. We hope to use this research to improve surgical care and quality of life for patients with hip problems, including hip dysplasia, femoroacetabular impingement (FAI), and the sequelae of childhood hip disease.

How are individuals selected for this study?

If eligible, patients undergoing hip preservation surgery will be asked to participate during their clinical appointment in our Palo Alto and Redwood City clinic locations.

Who is conducting this research and where is it being conducted?

The Principal Investigator for Stanford University is Dr. Stephanie Pun. Stanford University is 1 of 23 collaborating institutions for this data repository, with Washington University in St. Louis as the lead site.

Has recruitment started?

No. We plan on starting later in 2021.

I am interested in learning more, participating in, or have questions about this study. Who can I reach out to?

Please contact research coordinator, Ann Richey at arichey@stanford.edu with any and all study questions. If you would like to learn more about the ANCHOR group, please visit the website: https://www.anchorhipsurgeons.com

International Hip Dysplasia Registry (IHDR)

What is IHDR?

The International Hip Dysplasia Registry (IHDR) is a prospective cohort study conducted by the British Columbia Children’s Hospital in Vancouver, BC and ~20 other study institutions including Stanford Children’s Health. Developmental Dysplasia of the Hip (DDH) is a developmental condition describing a spectrum of hip abnormalities ranging in severity from mild hip instability to hip dislocation. DDH is the most common pediatric hip condition, with 1-3% of all newborns diagnosed at birth. Every child born is clinically screened for hip instability. Despite screening and treatment, DDH remains a major cause of early osteoarthritis of the hip and hip replacement in young adults. This prospective study is the first of its kind, both in size and scope, with the potential to have direct impact on treatment methods and standard of care for DDH around the world.

How are individuals selected for this study?

Patients ages 10 years and younger, who are referred for a DDH screening or diagnosed with DDH, and have care provided by one or both natural or adoptive parents may be eligible for this study.

Why is this research being conducted?

The purpose of this study is to develop a better understanding of DDH, including risk factors, screening or surveillance of the hip, and different treatment options such as bracing and surgery.

Who is conducting this research and where is it being conducted?

The Principal Investigator at Stanford is Dr. Stephanie Pun at Stanford Children’s Health. There are also over 20 other physicians at other institutions, nationally and internationally.

Has recruitment started?

Yes.

I am interested in learning more, participating in, or have questions about this study. Who can I reach out to?

Please contact research coordinator, Ann Richey at arichey@stanford.edu with any and all study questions. If you would like to read more about the IHDR prospective study or DDH, please visit https://bcchr.ca/IHDR, https://www.hipregistry.com/, or https://hipdysplasia.org/.

SCFE Longitudinal International Prospective (SLIP) Registry

What is the purpose of this registry?

The goal of the SCFE Longitudinal International Prospective (SLIP) Registry is to develop a data set of Slipped Capital Femoral Epiphysis (SCFE) cases from hospitals throughout the world, to better evaluate diagnosis and treatment practices. As there are multiple available surgical treatments for SCFE, it has been difficult to determine best practices in choosing a treatment option for a patient. Hospitals and surgeons throughout the world have different methods and reasoning behind these surgical treatment options for SCFE. Thus, there is a need to develop comprehensive, evidence-based guidelines for SCFE treatment. By participating in the SLIP Registry, we are helping to develop a prospective registry to evaluate current practices, better understand treatments for children and teenagers with SCFE, and determine which treatments may be the most appropriate and beneficial for each patient.

How are individuals selected for this study?

Patients under 18 years old with a confirmed diagnosis of SCFE will be asked if they would like to participate. Patients will be recruited during their follow-up appointments at participating centers.

Who is conducting this research and where is it being conducted?

The Principal Investigator at Stanford is Dr. Stephanie Pun at Stanford Children’s Health.

Has recruitment started?

Yes.

I am interested in learning more, participating in, or have questions about this study. Who can I reach out to?

Please contact research coordinator, Shayna Mehta at srmehta@stanford.edu with any and all study questions.

Short and Long Term Outcomes For Hip Preservation Surgey

Short and Long-Term Clinical Outcomes of Hip Preservation Study

What is the Short and Long-Term Clinical Outcomes of Hip Preservation Surgery study?

This study investigates the clinical outcomes of hip preservation surgery in children and young adults with hip disease, with special attention to hip dysplasia and femoroacetabular impingement (FAI). Patients' clinical pain and function will be evaluated before hip preservation surgery interventions and afterwards at various time points. The hip preservation surgeries of interest include periacetabular osteotomy (PAO), hip arthroscopy, surgical dislocation of the hip, and femoral osteotomy. Participants will fill out pre-operative and post-operative questionnaires to assess pain and function levels. Data including physical exam and imaging studies will also be collected pre-operatively, intra-operatively, and post-operatively as part of patients’ routine care. Short-term (2-5 years), mid-term (10-15 years) and long-term (20-40 years) outcomes will be evaluated.

How are individuals selected for this study?

We are recruiting patients ages 1 through 60 who have been identified as clinically needing hip preservation surgery.

Why is this research being conducted?

Hip preservation surgery is a relatively new field within orthopaedics, so it is important to identify the positive and negative risk factors for success or failure of hip preservation procedures. We hope to improve hip preservation surgical techniques through evaluation of patient outcomes.

Who is conducting this research and where is it being conducted?

The Principal Investigator is Dr. Stephanie Pun at Stanford Children’s Health. In certain cases, we may be assessing a smaller cohort of this study’s patient population in collaboration with other institutions such as Boston Children’s Hospital (BCH).

Has recruitment started?

Yes. If eligible, patients will be asked to participate during their clinical appointment in our Palo Alto and Redwood City clinic locations.

I am interested in learning more, participating in, or have questions about this study. Who can I reach out to?

Please contact research coordinator, Ann Richey at arichey@stanford.edu with any and all study questions.

Global DDH Care Map Initiative

Background:

Early signs of pediatric hip dysplasia, also known as Developmental Dysplasia of the Hip (DDH), are not always obvious. Frank hip dislocations occur in only about 1 of 1,000 infants, but other forms of hip instability are more common, and may be identified by careful physical examination. In some patients at certain ages, the use of ultrasound and/or x-ray is appropriate, to determine if referral for pediatric orthopedic care is needed. The 2014 American Academy of Orthopaedic Surgeons Clinical Practice Guideline on management of hip dysplasia has answered questions about clinical management, appropriate image evaluation, and referral for specialized treatment.

Dr. Kevin Shea and his collaborators have developed a DDH care map using evidence-based guidelines in North America to identify DDH in the first 12 months, a timeframe in which treatment intervention is highly successful and low cost. The purpose of the care map was to reduce variation in the treatment of DDH and reduce the cost via avoiding unnecessary testing, all to improve patient care. Some challenges the care map aimed to address were due to a lack of provider familiarity with DDH examination skills and the appropriate imaging tests and treatment.

The group received a national healthcare award in quality improvement for implementation in an Idaho healthcare system that serves both rural and metropolitan areas. During the first-year of implementation, several observations were made: 1) during routine infant care, 86% of primary care providers used the DDH care map in the first year, compared with less than 20% prior to implementation, 2) an increased rate of appropriate diagnostic imaging test ordering for DDH evaluation, and 3) after 18 months of implementation, no late presenting cases of DDH presentation were identified.

Global work:

In collaboration with the International Hip Dysplasia Institute (IHDI) at the University of British Columbia, we have expanded this DDH care map development work to a global scale. We have established partnerships with local orthopaedic surgeons, professional associations, and institutions in China, India, and Ecuador. In order to develop culturally and institutionally appropriate clinical pathways for DDH, surveys have been conducted in Canada, China, Ecuador, India, and the United States to better understand existing screening and treatment practices in each country. The results of the North American pediatric orthopaedic surgeon survey were recently published in the Journal of Pediatric Orthopaedics1, and survey results from China and India have been presented at the POSNA and COA conferences.

We are currently seeking funding mechanisms to support care map implementation in these developing countries. The goal is to implement evidence-based, culturally-tailored DDH care maps to increase primary care awareness of screening and referral guidelines. We will pilot this project throughout healthcare systems in one country first and develop novel dissemination strategies to scale up DDH care map utilization globally using previously established international DDH outcome networks. We hypothesize that DDH care map implementation will increase primary care provider awareness and utilization of screening guidelines, followed by an increase in the number of early referrals to specialists for low-cost, successful interventions for DDH.

References:

Taylor IK, Burlile JF, Schaeffer EK, et al. Developmental Dysplasia of the Hip: An Examination of Care Practices of Pediatric Orthopaedic Surgeons in North America. J Pediatr Orthop. 2020;40(4):e248-e255. doi:10.1097/BPO.0000000000001505

Swaddling Practices among Maternity Nurses

Knowledge and Practices of Hip-Healthy Newborn Swaddling Among Maternity Nurses

Infant swaddling is a common practice believed to soothe and facilitate sleep. Tight swaddling, with the hips adducted and extended, is associated with developmental dysplasia of the hip (DDH). Neonatal nurses are typically the first medical professional caregivers for infants. Dr. Stephanie Pun, Associate Professor in the Department of Orthopaedic Surgery at Stanford University, is the principal investigator. In the preliminary study, 104 neonatal nurses were surveyed. Researchers found that only 62.4% of nurses had received prior swaddling education and 18.4% of nurses were unable to identify the correct infant swaddling position. Dr. Stephanie Pun and her research team concluded that a required and evidence-based education for nurses on hip-healthy swaddling may help to decrease DDH throughout the community and increase correct swaddling practices.

Research Question:

Does a Required Hip-Healthy Swaddling Training Module Improve the Knowledge and Rate of Correct Lower Extremity Swaddling Practices in Maternal and Neonatal Nurses?

Dr. Stephanie Pun and her research team are now collaborating with nurses within Stanford Children’s Health to develop educational resources for infant swaddling techniques. The goal of this study is to develop and implement an educational training module for all maternity and neonatal nurses to complete. The module will educate nurses on infant hip development and DDH pathophysiology, discuss DDH risk factors and improper swaddling positions, demonstrate hip-healthy swaddling techniques, and provide links to hip health resources. Nurses will be surveyed pre- and post-training to assess knowledge and if the required training module is shown to be effective, Dr. Stephanie Pun hopes to expand the training program to additional pediatric care units at Stanford and other institutions across the nation with the support of the International Hip Dysplasia Institute (IHDI).

Clinical Associate Professor, Orthopaedic Surgery

Publications

No Delay in Age of Crawling, Standing or Walking with Pavlik Harness Treatment: A Prospective Cohort Study. The Journal of the American Academy of Orthopaedic Surgeons Stavinoha, T. J., Pun, S. Y., McGlothlin, J. D., Uzosike, M. B., Segovia, N. A., Imrie, M. N. 2023 More

Abstract

BACKGROUND: Pavlik harness treatment is the standard of care for developmental dysplasia of the hip in infants younger than 6 months. The effect of Pavlik harness treatment on the achievement of motor milestones has not previously been reported.METHODS: In this prospective cohort study, 35 patients were prospectively enrolled to participate and received questionnaires with sequential clinical visits monitoring treatment of their developmental dysplasia of the hip. One-sample Student t-tests assessed differences in milestone attainment age, and the Benjamini-Hochberg procedure was conducted to decrease the false discovery rate. Post hoc power analyses of each test were conducted. The age of achievement of eight early motor milestones were recorded and compared with a previously published cohort of healthy infants.RESULTS: Infants treated with a Pavlik harness achieved four early motor milestones markedly later than the reported age of achievement in a historical control group. These milestones included "roll supine" (5.3 vs. 4.5 months; P = 0.039), "roll prone" (5.7 vs. 5.0 months; P = 0.039), "sit" (6.4 vs. 5.2 months; P < 0.001), and "crawl on stomach" (7.7 vs. 6.6 months; P = 0.039). However, there was no difference in time to achievement of later motor milestones of "crawl on knees," "pull to stand," and "independent walking."CONCLUSION: Several early motor milestones were achieved at a statistically significantly later time than historical control subjects not treated in a Pavlik harness. Despite statistical significance, the small delays in early motor milestones were not thought to be clinically significant. No differences were observed in the later motor milestones, including knee crawling, standing, and independent walking. Clinicians and parents may be reassured by these findings.LEVEL OF EVIDENCE: Therapeutic Level II-prospective study.

View details for DOI 10.5435/JAAOS-D-21-00249

View details for PubMedID 37862341
Association of Hip Dysplasia With Trochlear Dysplasia in Skeletally Mature Patients. Orthopaedic journal of sports medicine Fithian, A. T., Richey, A. E., Sherman, S. L., Shea, K. G., Pun, S. Y. 2023; 11 (10): 23259671231200805 More

Abstract

Developmental dysplasia of the hip (DDH) and trochlear dysplasia (TD) are distinct pathologies with several important features in common. In addition to shared risk factors, both forms of dysplasia cause abnormal joint kinematics and force transmission, predisposing patients to pain, injuries to cartilage and soft tissue stabilizers, and ultimately arthritis.To evaluate for an association between hip dysplasia and TD in skeletally mature patients with symptomatic hip dysplasia.Cross-sectional study; Level of evidence, 3.A total of 48 patients with DDH who underwent periacetabular osteotomy were compared with 48 sex-matched patients who underwent hip arthroscopy for femoroacetabular impingement (FAI) between July 2014 and February 2021. All patients were skeletally mature. The Tönnis angle and lateral center-edge angle were measured on preoperative pelvis radiographs. Femoral version, trochlear depth, lateral trochlear inclination (LTI), tibial tubercle-trochlear groove distance (TTTG-d), and posterior lateral condylar angle (PLCA) were measured on preoperative magnetic resonance imaging scans of the symptomatic hip and ipsilateral knee. Continuous variables were compared between the patient groups using 2-sample t tests. Interobserver reliability was measured using the intraclass correlation coefficient.Patients with DDH demonstrated a reduced trochlear depth compared with patients with FAI (3.6 vs 4.6 mm; P < .001). There were no differences between groups in femoral anteversion, LTI, TTTG-d, or PLCA. Two (4.2%) patients with FAI and 17 (35.4%) patients with DDH had a trochlear depth <3 mm (P < .001). One (2.1%) patient with FAI and 7 (14.6%) patients with DDH had an LTI <11° (P = .027). There was no difference between groups in frequency of a convex proximal trochlea, patient-reported ipsilateral knee pain, or ipsilateral knee procedures.Patients with DDH had reduced trochlear depth compared with patients with FAI, demonstrating a higher incidence of dysplastic trochlear features that may predispose patients to patellofemoral joint disease. Further research is needed to determine whether screening at-risk patients and treating TD will help to prevent symptomatic patellofemoral disease.

View details for DOI 10.1177/23259671231200805

View details for PubMedID 37822419

View details for PubMedCentralID PMC10563471
Acetabular labral reconstruction with medial meniscal allograft: preliminary results of a new surgical technique. European journal of orthopaedic surgery & traumatology : orthopedie traumatologie Chen, M. J., Hollyer, I., Pun, S. Y., Bellino, M. J. 2021 More

Abstract

PURPOSE: Reconstruction of the acetabular labrum during femoroacetabular impingement (FAI) surgery is accepted when the labrum is deficient and irreparable. Here we describe a novel technique using fresh-frozen medial meniscal allograft for labral reconstruction during surgical hip dislocation for correction of pincer FAI due to acetabular overcoverage.METHODS: The results from seven hips (six patients) that underwent this procedure with 1 year minimum follow-up, and radiographs are presented.RESULTS: Six of the seven hips had improvements in pain, hip flexion, hip abduction, and Merle d'Aubigne-Postel scores. Only one patient with pre-existing osteoarthritis underwent reoperation with conversion to total hip arthroplasty. All digastric trochanteric osteotomies healed, and there were no cases of femoral head osteonecrosis or progression of Tonnis grades.CONCLUSIONS: The medial meniscus is a morphologically and clinically suitable option for labral reconstruction and effectively restores the hip fluid seal.

View details for DOI 10.1007/s00590-021-02986-2

View details for PubMedID 34028622
What Are the Early Outcomes of True Reverse Periacetabular Osteotomy for Symptomatic Hip Overcoverage? Clinical orthopaedics and related research Pun, S. Y., Hosseinzadeh, S., Dastjerdi, R., Millis, M. B. 2020 More

Abstract

BACKGROUND: Acetabular overcoverage is associated with pincer-type femoroacetabular impingement (FAI). A subtype of acetabular overcoverage is caused by a deep acetabulum with a negatively tilted acetabular roof, in which acetabular reorientation may be a preferable alternative to rim trimming to uncover the femoral head. We introduced the true reverse periacetabular osteotomy (PAO) in 2003, which in contrast to an anteverting PAO, also flexes and abducts the acetabulum relative to the intact ilium to decrease anterior and lateral femoral head coverage and correct negative tilt of the acetabular roof. To our knowledge, the clinical results of the true reverse PAO have not been evaluated.QUESTIONS/PURPOSES: For a group of patients who underwent reverse PAO, (1) Do patients undergoing reverse PAO demonstrate short-term improvement in pain, function, and hip ROM, and decreased acetabular coverage, as defined by lateral and anterior center-edge angle and Tonnis angle? (2) Are there identifiable factors associated with success or adverse outcomes of reverse PAO as defined by reoperation, conversion to THA, or poor patient-reported outcome scores? (3) Are there identifiable factors associated with early complications?METHODS: Between 2003 and 2017, two surgeons carried out 49 reverse PAOs in 37 patients. Twenty-five patients had unilateral reverse PAO and 12 patients had staged, bilateral reverse PAOs. To ensure that each hip was an independent data point for statistical analysis, we chose to include in our series only the first hip in the patients who had bilateral reverse PAOs. During the study period, our general indications for this operation were symptomatic lateral and anterior acetabular overcoverage causing FAI that had failed to respond to previous conservative or surgical treatment. Thirty-seven hips in 37 patients with a median (range) age of 18 years (12 to 41; interquartile range 16-21) were included in this retrospective study at a minimum follow-up of 2 years (median 6 years; range 2 to 17). Thirty-four patients completed questionnaires, 24 patients had radiographic evaluation, and 23 patients received hip ROM clinical examination. However, seven patients had not been seen in more than 5 years. The clinical and radiographic parameters of all 37 hips that underwent reverse PAO in 37 patients from a longitudinally maintained institutional database were retrospectively studied preoperatively and postoperatively. Adverse outcomes were considered conversion to THA or a WOMAC pain score greater than 10 at least 2 years postoperatively. Patient-reported outcomes, radiographic measurements, and hip ROM were evaluated preoperatively and at most recent follow-up using a paired t-test or McNemar test, as appropriate. Linear regression analysis was used to assess for identifiable factors associated with clinical outcomes. Logistic regression analysis was used to assess for identifiable factors associated with adverse outcomes and surgical complications. All tests were two-sided, and p values less than 0.05 were considered significant.RESULTS: At a minimum of 2 years after reverse PAO, patients experienced improvement in WOMAC pain (-7 [95% CI -9 to -5]; p < 0.001), stiffness (-2 [95% CI -3 to -1]; p < 0.001), and function scores (-18 [95% CI -24 to -12]; p < 0.001) and modified Harris Hip Score (mHHS) (20 [95% CI 13 to 27]; p < 0.001). The mean postoperative hip ROM improved in internal rotation (8° [95% CI 2° to 14°]; p = 0.007). Acetabular coverage, as defined by lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), and Tonnis angle, improved by -8° (95% CI -12° to -5°; p < 0.001) for LCEA, -12° (95% CI -15° to -9°; p < 0.001) for ACEA, and 9° (95% CI 6° to 13°; p < 0.001) for Tonnis angle. The postoperative severity of radiographic arthritis was associated with worse WOMAC function scores such that for each postoperative Tonnis grade, WOMAC function score increased by 12 points (95% CI 2 to 22; p = 0.03). A greater postoperative Tonnis grade was also correlated with worse mHHS, with an average decrease of 12 points (95% CI -20 to -4; p = 0.008) in mHHS for each additional Tonnis grade. Presence of a positive postoperative anterior impingement test was associated with a decrease in mHHS score at follow-up, with an average 23-point decrease in mHHS (95% CI -34 to -12; p = 0.001). Nineteen percent (7 of 37) of hips had surgery-related complications. Four hips experienced adverse outcomes at final follow-up, with two patients undergoing subsequent THA and two with a WOMAC pain score greater than 10. We found no factors associated with complications or adverse outcomes.CONCLUSION: The early clinical and radiographic results of true reverse PAO compare favorably to other surgical treatments for pincer FAI, suggesting that reverse PAO is a promising treatment for cases of pincer FAI caused by global acetabular overcoverage. However, it is a technically complex procedure that requires substantial training and preparation by a surgeon who is already familiar with standard PAO, and it must be carefully presented to patients with discussion of the potential risks and benefits. Future studies are needed to further refine the indications and to determine the long-term outcomes of reverse PAO.LEVEL OF EVIDENCE: Level IV, therapeutic study.

View details for DOI 10.1097/CORR.0000000000001549

View details for PubMedID 33296152
Is Increased Acetabular Cartilage or Fossa Size Associated With Pincer Femoroacetabular Impingement? Clinical orthopaedics and related research Pun, S. Y., Hingsammer, A., Millis, M. B., Kim, Y. 2017; 475 (4): 1013-1023 More

Abstract

Surgical treatment for pincer femoroacetabular impingement (FAI) of the hip remains controversial, between trimming the prominent acetabular rim and reverse periacetabular osteotomy (PAO) that reorients the acetabulum. However, rim trimming may decrease articular surface size to a critical threshold where increased joint contact forces lead to joint degeneration. Therefore, knowledge of how much acetabular articular cartilage is available for resection is important when evaluating between the two surgical options. In addition, it remains unclear whether the acetabulum rim in pincer FAI is a prominent rim because of increased cartilage size or increased fossa size.We used reformatted MR and CT data to establish linear length dimensions of the lunate cartilage and cotyloid fossa in normal, dysplastic, and deep acetabula.We reviewed the last 200 hips undergoing PAO, reverse PAO, and surgical dislocation for acetabular rim trimming at one institution. We compared MR images of symptomatic hips with acetabular dysplasia (20 hips), pincer FAI (29 hips), and CT scans of asymptomatic hips from patients who underwent CT scans for reasons other than hip pain (20 hips). These hips were chosen sequentially from the underlying pool of 200 potential subjects to identify the first 10 male and the first 10 female hips in each group that met inclusion criteria. As a result of low numbers, we included all hips that had undergone reverse PAO and met inclusion criteria. Cartilage width was measured medially from the cotyloid fossa to the lateral labrochondral junction. Cotyloid fossa linear height was measured from superior to inferior and cotyloid fossa width was measured from anterior to posterior. Superior lunate cartilage width (SLCW) and cotyloid fossa height (CFH) were measured on MR and CT oblique coronal reformats; anterior lunate cartilage width (ALCW), posterior lunate cartilage width (PLCW), and cotyloid fossa width (CFW) were measured on MR and CT oblique axial reformats. Cohorts were compared using multivariate analysis of variance with Bonferroni's adjustment for multiple comparisons.Compared with control acetabula, dysplastic acetabula had smaller SLCW (2.08 ± 0.29 mm versus 2.63 ± 0.42 mm, mean difference = -0.55 mm; 95% confidence interval [CI] = -0.83 to -0.27; p < 0.01), ALCW (1.20 ± 0.34 mm versus 1.64 ± 0.21 mm, mean difference = -0.44 mm; 95% CI = -0.70 to -0.18; p = 0.00), CFH (2.84 ± 0.37 mm versus 3.42 ± 0.57 mm, mean difference = -0.59 mm; 95% CI = -0.96 to -0.21; p < 0.01), and CFW (1.98 ± 0.50 mm versus 2.77 ± 0.33 mm, mean difference = -0.80 mm; 95% CI = -1.16 to -0.42; p < 0.0001). Based on the results, we identified two subtypes of deep acetabula. Compared with controls, deep subtype 1 had normal CFH and CFW but increased ALCW (2.09 ± 0.42 mm versus 1.64 ± 0.21 mm; p < 0.001) and PLCW (2.32 ± 0.36 mm versus 2.00 ± 0.32 mm; p = 0.04). Compared with controls, deep subtype 2 had increased CFH (4.37 ± 0.51 mm versus 3.42 ± 0.57 mm; p < 0.01) and CFW (2.76 ± 0.54 mm versus 2.77 ± 0.33 mm; p = 1.0) but smaller SCLW (2.12 ± 0.40 mm versus 2.63 ± 0.42 mm; p < 0.01).Deep acetabula have two distinct morphologies: subtype 1 with increased anterior and posterior cartilage lengths and subtype 2 with a larger fossa in height and width and smaller superior cartilage length.In patients with deep subtype 1 hips that have increased anterior and posterior cartilage widths, rim trimming to create an articular surface of normal size may be reasonable. However, for patients with deep subtype 2 hips that have large fossas but do not have increased cartilage widths, we propose that a reverse PAO that reorients yet preserves the size of the articular surface may be more promising. However, these theories will need to be validated in well-controlled clinical studies.

View details for DOI 10.1007/s11999-016-5063-1

View details for PubMedID 27637612
Hip dysplasia in the young adult caused by residual childhood and adolescent-onset dysplasia. Current reviews in musculoskeletal medicine Pun, S. 2016; 9 (4): 427-434 More

Abstract

Hip dysplasia is a treatable developmental disorder that presents early in life but if neglected can lead to chronic disability due to pain, decreased function, and early osteoarthritis. The main causes of hip dysplasia in the young adult are residual childhood developmental dysplasia of the hip (DDH) and adolescent-onset acetabular dysplasia. These two distinct disease processes affect the growing hip during different times of development but result in a similar deformity and pathomechanism of hip degeneration. Routine screening for DDH and counseling regarding risks for acetabular dysplasia in families with a history of early hip osteoarthritis may allow early identification and intervention in these hips with anatomical risk factors for joint degeneration.

View details for PubMedID 27613709
Review: femoroacetabular impingement. Arthritis & rheumatology Pun, S., Kumar, D., Lane, N. E. 2015; 67 (1): 17-27 More

View details for DOI 10.1002/art.38887

View details for PubMedID 25308887

View details for PubMedCentralID PMC4280287

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Faculty Contact

Dr. Stephanie Pun

Research Contact

Hiba Naz

hsidd@stanford.edu

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Hip Dysplasia Research

International Hip Dysplasia Registry (IHDR)

SCFE Longitudinal International Prospective (SLIP) Registry

Short and Long-Term Clinical Outcomes of Hip Preservation Study

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Faculty Contact

Dr. Stephanie Pun

Research Contact

Hiba Naz