Bone morphology and physical characteristics of the pro-cyclist hip joint.

PURPOSE: This study aimed to investigate the radiographic findings for the hip joint and hip range of motion in professional cyclists, and to determine their bone morphology and physical characteristics. The effects of physical characteristics on athletic performance were examined in terms of metabolic efficiency using simulation analysis. METHODS: We performed a case-control research study on 22 hips in 11 male professional cyclists (average age 28.5, height 1.73 m, weight 77.6 kg). Thirty hips in 15 healthy male volunteers were selected as controls. As radiographic evaluations, acetabular dysplasia was assessed on standardized radiographs. During physical evaluations, the hip range of motion was examined. We used simulation analysis to investigate the metabolic efficiency in the different cycling forms. RESULTS: The radiographic evaluations showed a significant difference in the incidence of acetabular dysplasia (p = 0.01): 59% (13/22 hips) in the pro-cyclist group versus 10% (3/30 hips) in the control group. The physical evaluations revealed significant differences in the hip internal rotation angle (p = 0.01), with greater ranges of internal rotation in the pro-cyclist group versus the control group. The simulation analyses showed that metabolism was reduced in the cycling form with hip internal rotation, especially in the lower extremities. CONCLUSIONS: Pro-cyclists showed a high frequency of acetabular dysplasia and superior hip internal rotation. According to the cycling model analyses, hip internal rotation allowed pedaling with reduced metabolic power.

Acetabular dysplasia and posterior wall fractures: The missing link?

BACKGROUND: Traumatologists are unable to predict hip instability based on CT scans and standard radiographs in posterior wall (PW) fractures comprising <50-60 % of the wall, necessitating an examination under anesthesia (EUA). Risk factors for instability have not been clarified, but acetabular dysplasia has been theorized as a potential etiology. Unfortunately, dysplasia is difficult to evaluate in the traumatic setting. The purpose of this study was to compare acetabular morphology between unstable and stable fractures with a novel method to detect dysplasia. METHODS: Patients ≥ 18 years old with a PW fracture that underwent an EUA from 2013 to 2023 were retrospectively identified. For our experimental measurements, the axial distances on CT between the acetabular dome, lateral acetabular opening, and femoral head vertex were recorded. Acetabular geometry was quantified at these levels. Conventional dysplasia metrics (e.g., Tonnis angle) were obtained. Variables were compared between stable and unstable fractures. RESULTS: 58 patients met inclusion criteria with 42 stable versus 16 unstable fractures. Unstable fractures had higher distances between the acetabular dome and femoral head vertex (p > 0.05). They had more cranial fracture exit points (p = 0.0015), lower femoral head coverage (p = 0.0102), and lower posterior acetabular sector angles (p = 0.0281). No other differences in acetabular geometry, demographics, injury characteristics, or other markers of dysplasia were identified. CONCLUSIONS: Unstable hips demonstrated a more recessed acetabular dome when compared to stable hips. Posterior acetabular femoral head coverage and cranial fracture exit point may be related to hip instability. A larger sample size is needed to validate these findings.

Modified triple pelvic osteotomy for residual acetabular dysplasia through double incisions: Technical note and review of short-term results.

PURPOSE: To assess validity, safety, and efficacy of the modified triple pelvic osteotomy (TPO) approach for correction of residual acetabular dysplasia. METHODS: This is a retrospective case series conducted on 15 hips in 15 patients from 2019 to 2023 with residual acetabular dysplasia treated by modified TPO as described by Tonnis with two modifications. The first modification is using a single medial incision for pubic and ischial cuts (the Vladimirov modification). The second modification is having the ischial cut closer to the acetabulum (Li modification) allowing free movement of the acetabular fragment for better femoral head coverage. The mean age at the time of surgery was 11.85 years, (range 8-23). Cases presenting were 10 males (66.7%) and 5 females (33.3%). The mean follow-up period was 36.533 months (24-60 months). RESULTS: Our study revealed significant clinical and radiological improvement. The CE angle improved from a mean value of 10° (range 2-17) pre-operatively to 32.785° (range 18°-40°) post-operatively. The AI improved from a mean value of 32° pre-operatively to a mean value of 13.89° post-operatively. HHS increased from a preoperative mean value of 74.80° to a post-operative mean value of 90.67°. Also, there was a significant improvement in ROM (abduction and internal rotation). LLD improved from a mean value of 2.60 cm preoperatively to a mean value of 0.37 cm postoperatively. Delayed union was found in 3 cases. No cases of osteonecrosis or neurovascular complication were encountered in our study. CONCLUSION: The modified TPO technique using dual incisions can be considered safe and effective, providing adequate coverage of the femoral head in acetabular dysplasia with less surgical time, satisfactory functional outcomes, and minimal complications. LEVEL OF EVIDENCE: IV.

Incidence, Prevalence, Risk Factors, and Clinical Treatment for Children with Developmental Dysplasia of the Hip in Saudi Arabia. A Systematic Review.

BACKGROUND: Developmental dysplasia of the hip (DDH) leads to pain, joint instability, and early degenerative joint disease. Incidence, prevalence, and management strategies of DDH have been well-documented in several countries, but not in Saudi Arabia. OBJECTIVE: We synthesized the current evidence regarding incidence, prevalence, risk factors, and clinical treatment for children with DDH in Saudi Arabia. METHODS: We searched 3 databases to locate studies. Studies that included children with DDH in Saudi Arabia; reported either incidence rate, prevalence, risk factors, and/or clinical practice; and were available in English or Arabic were included. We excluded reviews, case studies, or animal studies. Two independent authors reviewed potential studies and assessed study's quality. RESULTS: Our search yielded 67 potential studies, of which 16 studies were included (total DDH sample = 3,127; age range = 2.5 to 86.4 months). Three studies reported incidence rates ranging from 3.1 to 4.9 per 1000 births, and 3 studies reported prevalence ranging from 6 to 78%. Nine studies reported that female sex, breech position, family history, and age less than 3 years were risk factors associated with DDH. Four studies reported that brace applications and closed reduction were conservative treatments, and 9 studies reported that open hip reduction, adductor tenotomy, and/or pelvic osteotomy were surgical approaches to treat DDH. CONCLUSIONS: In Saudi Arabia, the Incidence and prevalence rates of DDH are 3.1 to 4.9 per 1,000 births, and 6-78%, respectively (differ from what has been reported in other countries), but the risk factors of DDH in Saudi Arabia appear to be similar in comparison to other countries (female, breech presentation, family history of DDH).

Primary Hip Arthroscopy in Patients With Acetabular Dysplasia: A Systematic Review of Published Clinical Outcomes at Minimum 5-Year Follow-up.

BACKGROUND: Hip arthroscopy in patients with borderline hip dysplasia has satisfactory outcomes at short-term follow-up; however, the data on midterm outcomes are inconsistent, and failure rates are high in some studies, limiting understanding of the role and utility of hip arthroscopy in this patient cohort. PURPOSE: To provide an up-to-date, evidence-based review of the clinical outcomes of primary hip arthroscopy in patients with frank or borderline hip dysplasia at ≥5-year follow-up and report the failure rate and progression to total hip arthroplasty in this cohort. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A comprehensive literature search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they evaluated outcomes of primary hip arthroscopy in patients with lateral center-edge angle (LCEA) <25° at ≥5-year follow-up. Risk of bias assessment was performed using the methodological index for non-randomized studies scoring system. Level of evidence was determined using criteria from the Oxford Centre for Evidence-Based Medicine. RESULTS: Nine studies were included in this review. Patients with LCEA <25° demonstrated satisfactory clinical outcomes, high patient satisfaction, and significant postoperative improvements in patient-reported outcomes (PROs) at follow-up ranging from a ≥5 to 10 years. Studies comparing patients with dysplasia to those without did not demonstrate significant differences in preoperative, postoperative, or delta PROs or in failure, reoperation, or revision rates. There was no overall significant correlation between outcomes and LCEA stratification. CONCLUSION: Hip arthroscopy in carefully selected patients with LCEA <25° can be successful at mid- to long-term follow-up and may provide clinical outcomes and failure rates comparable with patients with normal LCEA, understanding that this is a singular, 2-dimensional radiographic measure that does not differentiate instability from impingement or combinations thereof, warranting future studies delineating these differences. These findings suggest that hip dysplasia may not be an absolute contraindication for isolated hip arthroscopy and may serve as a viable intervention with consideration of staged future periacetabular osteotomy (PAO). Importantly, this review does not suggest that hip arthroscopy alters the natural history of dysplasia; therefore, patients with dysplasia should be counseled on the potential utility of PAO by appropriate hip preservation specialists.

Hip Preservation Surgery in Patients With Femoroacetabular Impingement Syndrome and Acetabular Dysplasia Improves Functional Measures and Pain Catastrophizing.

Background Chronic hip pain is a debilitating condition that severely reduces one's quality of life. Prior studies uncovered a link between hip pathologies and pain catastrophizing, anxiety, and depression. The purpose of this study was to investigate whether hip preservation surgery in patients with femoroacetabular impingement syndrome (FAIS) and acetabular dysplasia (AD) improves functional outcomes and pain catastrophizing. Methods Patients with FAIS and AD were requested to complete a hip questionnaire both preoperatively and postoperatively at a single academic center (University of Texas Southwestern Medical Center, Dallas, Texas, USA). Pain catastrophizing was evaluated using the pain catastrophizing scale, and pain level was assessed using the visual analog scale. Assessments of hip functional outcomes included the hip outcome score (HOS) and the hip disability and osteoarthritis outcome score (HOOS). Outcome measures before and after treatment were compared using the dependent samples t-test. A correlation analysis, using the Spearman partial correlation coefficient (rs), was conducted to evaluate the relationship between variables. Results The results indicated a clinically significant improvement in functional measures and pain catastrophizing in patients who underwent hip preservation surgery. The most significant discovery was an inverse relationship between both HOOS quality of life (rs=-0.293, p=0.0065, false discovery rate (FDR)=0.0210) and HOS activities of daily living (rs=-0.242, p=0.0254, FDR=0.0423) and pain catastrophizing; however, similar improvements were seen in pain catastrophizing with improvements in other functional outcomes. Conclusion Undergoing hip preservation surgery for patients with AD or FAIS improved their hip functional measures and decreased pain catastrophizing postoperatively. The improvement of hip function, quality of life, and pain catastrophizing reveals an intricate link between the functional outcomes of hip preservation surgery and pain catastrophizing.

The Proportion of Normalized Hips with Growth in Japanese Adolescents Aged > 10 years with Acetabular Dysplasia who Presented with Suspected Scoliosis.

Background: If asymptomatic acetabular dysplasia (AD) is incidentally identified in adolescence, it is difficult to determine the appropriate follow-up or treatment strategy because the acetabulum is still developing. We investigated the rate of AD normalization at the end of acetabular growth. Methods: This cross-sectional study involved 653 patients (1306 hips) aged 10-14 years with scoliosis or suspected scoliosis. All patients underwent plain standing whole-spine radiography (with the pelvis included) at the first visit. We measured the lateral center-edge angle, Sharp angle, Tönnis angle, and acetabular head index on radiographs. The criterion for AD was a lateral center-edge angle of < 20°. We extracted the data of patients aged < 12 (10-11) years and ≥ 12 (12-14) years with AD. Furthermore, we analyzed the radiographic follow-up data at 15 years of age to identify the AD normalization rate. Results: AD was diagnosed in 19 hips from patients aged < 12 years and in 36 hips from patients aged ≥ 12 years. The AD normalization rate at 15 years of age was 31.6% in those diagnosed at < 12 years of age and 5.6% in those diagnosed at ≥ 12 years of age. Conclusion: AD in adolescence was predictive of AD at the end of growth in 95% of cases diagnosed at ≥ 12 years of age compared with approximately 70% of cases diagnosed at < 12 years of age. Surgical treatment before completion of acetabular growth is beneficial for acetabular remodeling, but the decision to operate should be carefully evaluated in patients aged < 12 years. Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-023-01065-4.

Novel subtype of coxitis knee associated with acetabular dysplasia of the hip: a case series.

BACKGROUND: Multiple joint arthritis patterns require a comprehensive understanding to optimize patient management. This study aimed to present a patient cohort that deviated from known definitions of coxitis knee (CK), identifying and characterizing this atypical group. METHODS: Patients undergoing both total hip arthroplasty and total knee arthroplasty between January 2008 and December 2018 were retrospectively reviewed. The patients were classified into a typical coxitis knee group (classic, long leg arthropathy, and windswept deformity) and an atypical coxitis knee group. Leg-length discrepancy, body mass index (BMI), and radiographic parameters of the groups were compared and analyzed. RESULTS: A total of 31 patients were allocated to the typical coxitis knee group (n = 10), and atypical coxitis knee group (n = 21). In the atypical group, 27 hips were involved, of which 21 had acetabular dysplasia, 5 exhibited subchondral insufficiency fracture-like changes, and only 1 had classic osteoarthritis. Among the 27 knees undergoing total knee arthroplasty, 26 showed varus alignment, 1 was within the normal range, and none was valgus. Acetabular dysplasia involved ipsilateral (n = 1), contralateral (n = 14), and bilateral (n = 6) hips, showing atypical coxitis knee. Patients with acetabular dysplasia were more likely to exhibit atypical CK. CONCLUSION: Most patients in the cohort displayed acetabular dysplasia and contralateral varus knees, constituting a pattern referred to as acetabular dysplasia-associated gonarthritis. Identifying this novel subtype may have important clinical implications for regions with high risk factors, where acetabular dysplasia and constitutional genu varum are prevalent.

Non-Operative Rehabilitation Principles for Use in Individuals with Acetabular Dysplasia: A North American Based Delphi Study.

Background: Acetabular dysplasia (AD) is defined as a structurally deficient acetabulum and is a well-recognized cause of hip pain in young adults. While treatment of severe AD with a periacetabular osteotomy has demonstrated good long-term outcomes, a trial of non-operative management is often recommended in this population. This may be especially true in patients with milder deformities. Currently, there is a paucity of research pertaining to non-operative management of individuals with AD. Purpose: To present expert-driven non-operative rehabilitation guidelines for use in individuals with AD. Study Design: Delphi study. Methods: A panel of 15 physiotherapists from North America who were identified as experts in non-operative rehabilitation of individuals with AD by a high-volume hip preservation surgeon participated in this Delphi study. Panelists were presented with 16 questions regarding evaluation and treatment principles of individuals with AD. A three-step Delphi method was utilized to establish consensus on non-operative rehabilitation principles for individuals presenting with AD. Results: Total (100%) participation was achieved for all three survey rounds. Consensus, defined a piori as > 75%, was reached for 16/16 questions regarding evaluation principles, activity modifications, appropriate therapeutic exercise progression, return to activity/sport criteria, and indications for physician referral. Conclusion: This North American based Delphi study presents expert-based consensus on non-operative rehabilitation principles for use in individuals with AD. Establishing guidelines for non-operative management in this population will help reduce practice variation and is the first step in stratifying individuals who would benefit from non-operative management. Future research should focus on patient-reported outcomes and rate of subsequent surgical intervention to determine the success of the guidelines reported in this study. Level of Evidence: Level V.

Acetabular index as an indicator of Pavlik harness success in grade I developmental dysplasia of the hip: A retrospective study.

Purpose: Some articles have focused on the effectiveness of the Pavlik harness treatment for unstable and dislocated hips, yet data on monitoring its effectiveness with the acetabular index remains elusive. Therefore, this study aimed to assess Pavlik harness effectiveness in infants ≤6 months diagnosed with grade I developmental dysplasia of the hip using acetabular index improvement and identify the possible predictors of successful Pavlik harness treatment. Methods: A retrospective review of infants with grade I acetabular dysplasia treated with a Pavlik harness and monitored with anteroposterior pelvis X-rays at presentation and follow-up. Successful treatment was defined as achieving an acetabular index <30°. Results: A total of 231 infants with acetabular dysplasia were treated with a Pavlik harness. A successful outcome was achieved in 135 infants (58.4%). Younger age, lower initial acetabular index, and patients with unilateral developmental dysplasia of the hip were significant predictors of a successful outcome. An age of 4.5 months or older was found to be the threshold for an unsuccessful result following Pavlik harness treatment, with a sensitivity of 65.2% and specificity of 57.3%. An initial acetabular index of 35.5° was found to be the threshold for an unsuccessful result, with a sensitivity of 83.7% and specificity of 61.5%. Conclusion: Pavlik Harness's success in correcting the acetabular index in acetabular dysplasia patients was related to unilateral cases, a younger age at presentation, and a lower initial acetabular index. The thresholds for unsuccessful treatment were an age of 4.5 months or greater and an acetabular index of 35.5° or higher.

Birmingham Royal Orthopaedic Hospital (BROH) Femoral Offset-An Ancillary Measure of Adult Dysplasia of the Hip.

Introduction Adult dysplasia of the hip (ADH) is a disorder of abnormal development of the hip joint resulting in a shallow acetabulum and uncovering of the femoral head. Several radiological measurements such as the Tönnis angle (acetabular index), lateral center edge angle of Wiberg, and cross-sectional imaging parameters exist to calculate hip dysplasia. Aims The aim of this article was to describe a new ancillary linear measure of ADH on cross-sectional imaging, the Birmingham Royal Orthopaedic Hospital (BROH) Femoral offset. Patients and Methods Anteroposterior radiographs of the pelvis and computed tomography imaging of 100 consecutive patients with suspected hip dysplasia were reviewed. Demographic details and clinical indications were recorded. Tönnis angle was utilized to measure hip slope on radiographs and the BROH femoral offset was calculated for each patient. Student's t -test and one-way analysis of variance (ANOVA) were performed. Intraclass correlation coefficient analysis was evaluated to assess the reliability between observers. Results There was a total of 100 patients (128 hips) included in the study (60 with normal Tönnis angle, 53 had dysplasia, and 15 had decreased Tönnis angle). The average BROH femoral offset in the dysplastic cohort was increased in comparison to the normal cohort with a statistically significant p -Value of 0.0001. The p -value was 0.00031 on ANOVA. The BROH femoral offset calculation revealed good intra- and interobserver reliability of 0.9 and 0.9, respectively. Conclusion The BROH femoral offset can be an additional index for measuring ADH that is easier to calculate, and reproducible with good intra- and inter-observer reliability on cross-sectional imaging.

Advances in fixation strength of reorienting rectangular triple pelvic innominate osteotomies - A biomechanical investigation of two screw fixation techniques.

BACKGROUND: Reorientating pelvic osteotomies are performed to prevent femoral-acetabular impingement or degenerative arthritis. A Toennis-Kalchschmidt triple pelvis innominate osteotomy is used in symptomatic patients. This study aimed to investigate the biomechanical behaviour of two different acetabular screw configurations for triple pelvis innominate osteotomy osteosynthesis. METHODS: Two screw-orientation techniques in rectangular os ilium osteotomy were compared by osteotomising 12 artificial hemipelvises with triple pelvis innominate osteotomy protocol (fragment reorientation: 10.5° inclination and 10.0° anteversion) and randomising them in 2 groups (n = 6) for implantation with three 4.5 mm screws. Bidirectional group had a bidirectional screw orientation and Monoaxial group had a monoaxial direction of all three screws through iliac crest. All specimens were tested under progressively increasing cyclic loading until failure. Group-wise comparisons of acetabular cup medialisation, anteversion and inclination were evaluated via motion tracking at cycles 250, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, and 2500. Failure was defined as reaching 5° inclination or 5° anteversion. FINDINGS: Acetabular cup medialisation (p ≤ 0.026), anteversion (p ≤ 0.021) and inclination (p ≤ 0.039) all increased significantly during testing in both groups. There were no significant differences for the group-wise comparisons at the cycle points defined in the methods (p ≥ 0.182). No significant differences were detected between groups for cycles to failure and failure load (p = 0.873). INTERPRETATION: Bidirectional screw alignment does not lead to significant advantages compared to pure monoaxial if all three axial screws are evenly distributed over the osteotomy geometry. The triple pelvis innominate osteotomy is susceptible to changes in anteversion, inclination and medialisation under partial weight-bearing. Cautious rehabilitation protocols are recommended.

Residual acetabular dysplasia after Pavlik harness treatment for Graf type II hips.

Purpose: To evaluate the residual acetabular dysplasia in Graf type II hips after Pavlik harness treatment with a radiographic follow-up at 2 years of age. Methods: We retrospectively reviewed the developmental dysplasia of the hip patients who were treated with the Pavlik harness between March 2018 and February 2022. Patients with Graf type II hip dysplasia who had at least one radiographic follow-up after 2 years of age were included. The following information, sex, laterality, affected side, age at harness initiation, treatment duration, α angle, and the morphology of bony roof, was collected and studied. We evaluated the radiographic acetabular index at the last follow-up and defined the value of greater than 2 standard deviations as residual acetabular dysplasia. Results: A total of 33 patients (53 hips) met the criteria. The mean initial α angle was 53.4°; the mean age at Pavlik harness initiation was 10.9 weeks. The mean treatment duration was 10 weeks. The mean α angle at the last ultrasound follow-up was 64.9°. The mean age of the last radiographic follow-up was 2.6 years, and 26 hips had a residual acetabular dysplasia with acetabular indexes greater than 2 standard deviations above the mean. The morphology of the acetabular bony rim (odds ratio = 4.333, P = 0.029) and age of initial treatment <12 weeks (odds ratio = 7.113, P = 0.014) were seen as significant predictors for a higher acetabular index more than 2 years of age. Conclusions: A notable incidence of residual acetabular dysplasia after Pavlik harness treatment in Graf type II hips, wherein the acetabular bony roof with a blunt rim at the end of treatment and initial age after 12 weeks were independent predictors associated with residual acetabular dysplasia. Levels of evidence: Therapeutic studies, IV.

Definition of hip displacement and dislocation by acetabular dysplasia in children with cerebral palsy.

Purpose: The acetabulum interacts with the femoral head in daily activities and may exhibit structural changes in the presence of hip disorders. This study aims to redefine hip disorders in children with cerebral palsy by structural characteristics of the acetabulum in relation to the degree of the migration percentage. Methods: The clinical and radiographic data of 70 patients (36 males, 34 females; mean age 8.2 years) with spastic cerebral palsy were retrospectively analyzed. The acetabular structure was measured by the acetabular index on reconstructed three-dimensional computerized tomography for precision of measurement. Any significant change in acetabular index measured on the reconstructive computerized tomography related to every 10% increment of migration percentage was regarded as clinically significant in hip disorders. Results: The acetabular index measured on the reconstructive computerized tomography showed an increasing trend with the increment of migration percentage. The most significant acetabular index measured on the reconstructive computerized tomography change occurred between the 20%-29% and 30%-39% migration percentage groups (p < 0.001), suggesting that a migration percentage of 30% is the starting point of hip disorder. A significant increase in the posterolateral acetabular index measured on the reconstructive computerized tomography occurred in migration percentages >50%, indicating posterolateral acetabular dysplasia. Hips with migration percentages from 80% to 100% had consistent acetabular indexes measured on the reconstructive computerized tomography values, suggesting complete dislocation and no more contact and interaction between the femoral head and acetabular fossa. Conclusion: Structural characteristics in the acetabulum reflect hip dysfunction and potentially classify hip disorders. Results suggest the migration percentage 30% as a starting point of hip disorder and 80% as a turning point of hip dislocation in children with cerebral palsy. Level of evidence: level IV, diagnostic study.

Defining the Borderline Dysplastic Hip: High Variability in Acetabular Coverage and Femoral Morphology on Low-Dose Computed Tomography.

BACKGROUND: Borderline acetabular dysplasia is commonly radiographically defined as a lateral center-edge angle (LCEA) of 20° to 25°. While the variability of plain radiographic assessment of this population has been reported, an understanding of the variability of 3-dimensional (3D) hip morphology remains to be better defined. PURPOSE: To investigate the variability of 3D hip morphology present on low-dose computed tomography (CT) in the setting of symptomatic borderline acetabular dysplasia and to determine if plain radiographic parameters correlate with 3D coverage. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: A total of 70 consecutive hips with borderline acetabular dysplasia undergoing hip preservation surgery were included in the current study. Plain radiographic evaluation included LCEA, acetabular inclination, anterior center-edge angle (ACEA), anterior wall index (AWI), posterior wall index (PWI), and alpha angles on anteroposterior, 45° Dunn, and frog-leg views. All patients underwent low-dose pelvic CT for preoperative planning, which allowed detailed characterization of 3D morphology relative to normative data. Acetabular morphology was assessed with radial acetabular coverage (RAC) calculated according to standardized clockface positions from 8:00 (posterior) to 4:00 (anterior). Coverages at 10:00, 12:00, and 2:00 were classified as normal, undercoverage, or overcoverage relative to 1 SD from the mean of normative RAC values. Femoral morphology was assessed with femoral version, alpha angle (measured at 1:00 increments), and maximum alpha angle. Correlation was assessed with the Pearson correlation coefficient (r). RESULTS: Lateral coverage (12:00 RAC) was deficient in 74.1% of hips with borderline dysplasia. Anterior coverage (2:00 RAC) was highly variable, with 17.1% undercoverage, 72.9% normal, and 10.0% overcoverage. Posterior coverage (10:00 RAC) was also highly variable, with 30.0% undercoverage, 62.9% normal, and 7.1% overcoverage. The 3 most common patterns of coverage were isolated lateral undercoverage (31.4%), normal coverage (18.6%), and combined lateral and posterior undercoverage (17.1%). The mean femoral version was 19.7°± 10.6° (range, -4° to 59°), with 47.1% of hips having increased femoral version (>20°). The mean maximum alpha angle was 57.2° (range, 43°-81°), with 48.6% of hips having an alpha angle ≥ 55°. The ACEA and AWI were poorly correlated with radial anterior coverage (r = 0.059 and 0.311, respectively), while the PWI was strongly correlated with radial posterior coverage (r = 0.774). CONCLUSION: Patients with borderline acetabular dysplasia demonstrate highly variable 3D deformities, including anterior, lateral, and posterior acetabular coverage; femoral version; and alpha angle. Plain radiographic assessments of anterior coverage are poorly correlated with anterior 3D coverage on low-dose CT.

Long-term results of Chiari pelvic osteotomy on the preservation of hip function with mean follow-up of more than 30 years and its prognostic factors.

BACKGROUND: Clinical outcomes of Chiari pelvic osteotomy for acetabular dysplasia, including conversion to total hip arthroplasty (THA), have not been adequately explored. The purpose of this study was to examine the long-term results and clinical outcomes of Chiari pelvic osteotomy as the primary outcome and to analyze its prognostic factors as the second outcome. METHODS: This study was a multicenter, retrospective cohort study. Ninety-seven patients underwent Chiari pelvic osteotomy at three hospitals between March 1975 and October 1997. The long-term clinical outcomes of Chiari pelvic osteotomy, including conversion to THA and hip pain, were analyzed using the Kaplan-Meier method. In addition, the prognostic factors for conversion to THA after Chiari pelvic osteotomy were evaluated with clinical variables and radiographic parameters. RESULTS: The study included 51 hips in 45 patients (4 men and 41 women) with long-term follow-up. The survival rates assessed by Kaplan-Meier analysis with conversion to THA as an endpoint, were 90.2% (95% confidence interval (CI) 82.0-98.4%) at 20 years and 73.5% (95% CI 61.1-86.0%) at 30 years. In contrast, the Kaplan-Meier survival rates with the Japanese Orthopaedic Association hip score for pain ≤20 as an endpoint, were 86.3% (95% CI 76.8-95.7%) at 20 years and 65.6% (95% CI 52.3-79.0%) at 30 years. Only older age at osteotomy was the significantly poor prognostic factor for conversion to THA, with a hazard ratio of 1.11/year, 95% CI 1.06 to 1.18, (p < 0.01). CONCLUSION: Chiari pelvic osteotomy may still be a good alternative to bony reconstructive surgery for acetabular dysplasia especially in young patients. Only older age at the osteotomy was related to the poor prognosis of preserving hip function.

Mean 14-year Outcomes of Hybrid Total Hip Arthroplasty Using Bulk Femoral Head Autografts for Acetabular Reconstruction.

BACKGROUND: We aimed to evaluate the mean 14-year outcomes of hybrid total hip arthroplasty (THA) with cementless acetabular cups using bulk femoral head autografts in acetabular reconstruction and specify the radiological characteristics of cementless acetabular cups using this technique. METHODS: This retrospective study included 98 patients (123 hips) who underwent hybrid THA with a cementless acetabular cup using bulk femoral head autografts for bone deficiency in acetabular dysplasia and who were followed-up for a mean of 14 years (range, 10 to 19.6). The percentage of bone coverage index (BCI) and cup center-edge (CE) angles were evaluation radiologically of acetabular host bone coverage. The survival rate of the cementless acetabular cup and autograft bone ingrowth were assessed. RESULTS: The survival rate with all revisions of cementless acetabular cups was 97.1% (95% confidence interval: 91.2 to 99.1). The autograft bone was remodeled or reoriented in all cases except in 2 hips where the bulk femoral head autograft collapsed. Radiological evaluation revealed a mean cup CE angle of -17.8° (range, -52 to -7°) and a BCI of 44.4% (range, 10 to 75.4%). CONCLUSION: Cementless acetabular cups using bulk femoral head autografts for bone deficiency of the acetabular roof remained stable even if the average BCI was 44.4% and the average cup CE angle was -17.8°. Cementless acetabular cups using these techniques showed good 10-year to 19.6-year outcomes and viabilities of graft bones.

MRI May Be More Valuable than Pelvic Radiographs in the Assessment of Paediatric Borderline Acetabular Dysplasia.

The osseous acetabular index (OAI) and cartilaginous acetabular index (CAI) is often used in diagnosing acetabular dysplasia (AD) in children. We examined the reliability of OAI and CAI in AD diagnostics and compared OAI measurements obtained from radiographs versus MRI. Four raters performed retrospective repeated measurements of the OAI and CAI on pelvic radiographs and MRI scans of 16 consecutive patients (mean age 5 years (2-8)) examined for borderline AD during a period of 2½ years. In MRI, the image selected for analysis by the raters was also registered. Spearman's correlation, scatter plots, and Bland-Altman (BA) plots were analysed for correlation between OAI on pelvic radiographs (OAIR) and MRI scans (OAIMRI), while intra- and interrater reliability was assessed for OAIR, OAIMRI, CAI, and MRI image selection using intraclass correlation coefficients (ICC). ICC values for inter- and intrarater reliability of OAIR, OAIMRI, and CAI were all above 0.65, with no significant differences observed. ICC values (CI) for individual raters' MRI image selection was 0.99 (0.998-0.999). The mean difference (95% CI) between OAIR and OAIMRI was -0.99 degrees (-1.84; -0.16), while the mean absolute difference (95% CI) between OAIR and OAIMRI was 3.68 degrees (3.17; 4.20). Absolute differences between OAIR and OAIMRI was independent of pelvic positioning or time interval between radiographs and MRI scans. OAI and CAI had high Intrarater reliability but mediocre interrater reliability. There was an absolute difference of 3.7 degrees in OAI between pelvic radiographs and MRI scans.

Subchondral fatigue fracture of the femoral head with acetabular dysplasia treated by transposition osteotomy of the acetabulum: a case report.

Introduction: Subchondral insufficiency fracture of the femoral head commonly occurs in older women with osteoporosis. However, subchondral fatigue fracture of the subchondral femoral head is rare. We present a rare case of fatigue fracture of the subchondral femoral head with acetabular dysplasia. Case Report: The patient was a 16-year-old male, height 180 cm, weight 112 kg, and body mass index 34.6 kg/m2. Continuous right hip pain appeared after club activity of table tennis a month before admission to our department. Pain was observed on deep flexion of the right hip joint. The FADIR test was positive. X-ray images showed a depressed deformity of the right femoral head loading portion. In addition, the center-edge angle was 10° on the right and 21° on the left, tear drop distance was 12 mm on the right and 8 mm on the left, and bilateral acetabular dysplasia was noted. In magnetic resonance imaging, the T1-weighted image shows low-intensity signal and the T2-weighted image shows high-intensity signal, indicating a fatigue fracture of the femoral head with subchondral depression. Thus, transposition osteotomy of the acetabulum was performed in this case. Postoperatively, the depression portion showed gradual remodeling, and the patient returned to sports after 6 months. Because this patient was highly obese with acetabular dysplasia, a large shear force was applied to the loading portion of the femoral head relative to the acetabular rim. The femoral head was repeatedly forced, resulting in a fatigue fracture. We believe that the stress applied to the depressed portion was dispersed by the transposition osteotomy of the acetabulum, resulting in remodeling. Conclusion: This is the first report of the transposition osteotomy of the acetabulum for a subchondral fatigue fracture of the femoral head with acetabular dysplasia. Thus, this may serve as a reference in the management of such rare occurrences and pave the way for further understanding of this condition.

Retrotilt of the Pelvis During Periacetabular Osteotomy: How to Avoid a Systematic Error Resulting in Acetabular Retroversion and Possible Femoroacetabular Impingement.

BACKGROUND: Pelvic tilt directly influences acetabular version on radiographs. Changes of pelvic tilt potentially affect acetabular reorientation after periacetabular osteotomy (PAO). PURPOSE: (1) To compare the ratio of the pubic symphysis height to the sacroiliac width (PS-SI) between hips with dysplasia and acetabular retroversion, uni- and bilateral PAO, and male and female patients. (2) To evaluate pelvic tilt (quantified using the PS-SI ratio) in patients after PAO by tracking it from preoperative to intra- and postoperative and short- and middle-term follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective and radiographic study was conducted evaluating pelvic tilt in 124 patients (139 hips) with dysplasia and 46 patients (57 hips) with acetabular retroversion who were undergoing PAO (January 2005-December 2019). Patients were excluded if they had insufficient radiographic data, previous or concomitant hip surgery, posttraumatic or pediatric deformities, or combined dysplasia and retroversion (90 patients, 95 hips). Dysplasia was defined as a lateral center-edge angle <23°; retroversion was defined by simultaneous appearance of a retroversion index 30% and positive ischial spine and posterior wall signs. Anteroposterior pelvic radiographs were taken in the supine position preoperatively, during PAO, postoperatively, and at short- and middle-term follow-up (mean ± SD [range]; 9 ± 3 weeks [5-23 weeks] and 21 ± 21 weeks [6-125 months]). The PS-SI ratio was calculated at 5 observation periods (preoperatively to middle-term follow-up) for different subgroups (dysplasia vs retroversion, uni- vs bilateral surgery, male vs female) and validated with intra- and interobserver agreement (intraclass correlation coefficients, 0.984 (95%CI, 0.976-0.989) and 0.991 (95% CI, 0.987-0.994), respectively). RESULTS: The PS-SI ratio differed between dysplasia and retroversion at all observation periods (P = .041 to P < .001). Male dysplastic hips had a lower PS-SI ratio when compared with female dysplastic hips at all observation periods (P < .001 to P = .005). In hips with acetabular retroversion, the PS-SI ratio was lower in men than women at short- and middle-term follow-up (P = .024 and .003). No difference was found between uni- and bilateral surgery (P = .306 to P = .905) except for short-term follow-up in dysplasia (P = .040). The PS-SI ratio decreased in all subgroups preoperatively to intra- or postoperatively (P < .001 to P = .031). At short- and middle-term follow-up, the PS-SI ratio increased as compared with intraoperatively (P < .001 to P = .044) and did not differ from preoperatively in all subgroups (P = .370 to P = .795). CONCLUSION: A lower PS-SI ratio was found for male or dysplastic hips. In all subgroups, the PS-SI ratio decreased during surgery, indicating retrotilt of the pelvis. Correct pelvic orientation during surgery is crucial for accurate acetabular reorientation. Retrotilt during surgery results in underestimation of acetabular version and iatrogenic retroversion of the acetabulum at follow-up, with the pelvis in the correct and more forward-tilted orientation. Not taking into account retrotilt during PAO potentially results in femoroacetabular impingement. Therefore, we changed our intraoperative setting with adjustment of the central beam to compensate for retrotilt of the pelvis.