Mean Lateral Center-edge Angle Research Articles

Prognosticating Residual Dysplasia at Skeletal Maturity Following Closed Reduction for Developmental Dysplasia of the Hip: A Long-Term Study with an Average 20-Year Follow-up.

Patients with developmental dysplasia of the hip (DDH) are at risk for residual acetabular dysplasia even after successful closed reduction. The aim of this study was to identify predictors of long-term outcomes in order to guide prognostication and management. Patients who were treated for DDH at 2 institutions between 1970 and 2010 and had follow-up until skeletal maturity were screened for inclusion. Hips that underwent open reduction were excluded to reduce iatrogenic confounding. Syndromal (including neuromuscular and arthrogrypotic) hip instability with collagenopathies were excluded. Demographic characteristics, Tönnis grade, age at the time of the reduction, surgical treatment, acetabular index, lateral center-edge angle, residual dysplasia graded using the Severin classification, and the presence and type of proximal femoral growth disturbance categorized using the Bucholz and Ogden classification were assessed. In addition, the the acetabular angle was recorded at the latest follow-up before secondary procedures, and the Oxford Hip Score and 5-level EuroQoL (EQ)-5 Dimension score were recorded at the latest follow-up. To account for repeated measures, generalized estimating equations (GEE) logistic regression was utilized for the multivariable analysis. A support vector machine model and a receiver operating characteristic curve analysis were utilized to identify prognostication thresholds. One hundred and seven hips (96 female, 11 male) that were followed to skeletal maturity, with a mean follow-up of 20 years (range, 10 to 54 years), were included in the analysis. Eighty-nine hips (83%) demonstrated a good outcome at skeletal maturity, with a Severin grade of I or II. Major growth disturbances of Bucholz and Ogden types II, III, or IV were present in 13 hips (12%). At the latest follow-up after skeletal maturity (before any secondary procedures), the mean acetabular angle was 45° ± 4° and the mean lateral center-edge angle was 26° ± 8°. The mean Oxford Hip Score and EQ visual analog scale values were 47 and 86, respectively. A GEE logistic regression analysis of 1,135 observations revealed that the acetabular index (odds ratio [OR], 1.16 per degree; p < 0.001) and age (OR, 1.20 per year; p = 0.003) were significant predictors of a poor outcome (i.e., Severin grade III, IV, or V). Significant differences in acetabular indices across all age groups were found between hips with a good outcome and those with a poor outcome. Age-specific acetabular index prognostication cutoff values are presented. This long-term follow-up study demonstrated that the age-specific acetabular index remains an important predictor of residual dysplasia at skeletal maturity. The proposed prognostication chart and thresholds herein can help to guide orthopaedic surgeons and parents when contemplating the use of an intervention versus surveillance to optimize long-term outcomes. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Poster 181: Hip Arthroscopy with Concomitant Periacetabular Osteotomy Demonstrates Excellent Outcomes and Survivorship at Minimum 10-Year Follow-Up

Objectives: Multiple studies have shown that hip arthroscopy with concomitant periacetabular osteotomy (PAO) is a safe and effective treatment option for patients presenting with Symptomatic acetabular dysplasia and intra-articular pathology. While excellent short- and mid-term outcomes have been previously reported, there exists a paucity of literature investigating long-term outcomes of hip arthroscopy with concomitant PAO. The purpose of this study was to report minimum 10-year follow-up results and survivorship of hip arthroscopy with concomitant PAO to treat acetabular dysplasia and intraarticular pathologies such as femoroacetabular impingement (FAI) and labral tears. Methods: Data from October 2010 to December 2012 was prospectively collected and retrospectively reviewed to identify patients undergoing hip arthroscopy with concomitant PAO. Patients were included in the present analysis if they had preoperative and minimum 10-year patient reported outcomes (PROs) documented for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Scored Sports-Specific Subscale (HOS-SSS), and pain on a visual analog scale (VAS), as well as the International Hip Outcome Tool (iHOT-12) and patient satisfaction score on a 0-10 scale. Results: Fifteen patients were eligible for analysis and 12 had complete minimum 10-year follow-up (80.0%) at mean 10.2 years postoperation. There were 10 females (83.3%) and 2 males (16.7%) included in the study with a mean age and BMI of 24.4 years and 24.5 kg/m2, respectively. The mean lateral center-edge angle (LCEA) of all included hips in the analysis increased from 13.8° to 29.8° postoperatively ( P&lt;0.05) and the anterior center-edge angle (ACEA) increased from 14° to 28.8° postoperatively ( P&lt;0.05). Additionally, the Tönnis angle of acetabular inclination decreased from 17.9° to 7.3° postoperatively ( P&lt;0.05) and the alpha angle decreased from 56.5° to 52.1° postoperatively ( P&lt;0.05). There was significant improvement in all PROs from baseline to minimum 10-year follow-up (mHHS; NAHS; HOS-SSS, P&lt; 0.05). All patients achieved high rates of MCID for mHHS, NAHS, and HOS-SSS, as well as high rates of PASS for mHHS and VAS. The 10-year survivorship for all patients included in the analysis was 83.3% with 2 patients (16.7%) progressing to total hip arthroplasty (THA) at mean 58.0 months postoperatively. Additionally, 2 patients (16.7%) underwent subsequent ipsilateral revision hip arthroscopy at mean 79.5 months postoperatively. Conclusions: Patients with dysplasia and intra-articular pathology such as labral tears and FAI can be safely treated using hip arthroscopy with concomitant PAO. These patients can achieve excellent long-term outcomes and high rates of survivorship at minimum 10 years postoperation.

Dysplastic Hips Have Decreased Iliofemoral Ligament Thickness on Coronal Sequences in Magnetic Resonance Imaging: A Matched Cohort Analysis

To characterize hip capsule thickness on advanced imaging in patients with and without hip dysplasia and to also evaluate differences in capsular thickness between patients with borderline and patients with true dysplasia. Patients evaluated by the senior author for concerns of hip pathology from June 2020 to June 2021 were queried and images reviewed to determine dysplasia status by lateral center-edge angle (LCEA) ≤25°. A group of patients without dysplasia was identified and matched for age, sex, and body mass index. Hip capsular thickness was quantified using magnetic resonance imaging. A subanalysis was conducted to compare patients with true dysplasia (LCEA < 20°) with patients with borderline dysplasia (LCEAs between 20° and 25°). The analysis included independent samples t tests, χ2 tests, and multivariable regression. A total of eighty patients were included, with a mean age of 31.8 ± 11.7 years, a mean body mass index of 26.6 ± 6.5 points, and 70% (56) female patients. Patients with dysplasia had a mean LCEA of 19.8 ± 4.3°. Patients with dysplasia had decreased capsular thickness compared with patients without dysplasia (2.75 ± 0.96 mm vs 3.52 ± 1.22 mm, P= .003). Multivariable regression showed decreased capsular thickness associated with decreased LCEAs (β= 2.804, R= 0.432, P < .001) and dysplasia (β= -0.709, R2= 0.056, P= .004). Results of a subanalysis of the dysplastic group examining differences between accepted definitions of borderline dysplasia and true dysplasia showed no significant differences in capsular thickness between the 2 groups (P= .379). Patients with hip dysplasia were found to have thinner iliofemoral ligaments in the coronal plane on magnetic resonance imaging on magnetic resonance imaging. Further investigation is needed to evaluate any potential implications with hip instability, given the thinner hip capsule demonstrated in this study. Level III, retrospective comparative prognostic trial.

Prevalence of Acetabular Dysplasia at a Mean age of 18 Years After Treatment for Neonatal hip Instability.

The long-term radiological outcomes after the treatment of neonatal hip instability (NHI) in developmental dysplasia of the hip are unclear. Therefore, the prevalence of acetabular dysplasia at a mean age of 18 years after treatment was investigated. The relationship between acetabular dysplasia and hip discomfort has also been poorly established. Therefore, the differences in pain, hip-related quality of life (QOL), and hip impingement tests in hips with and without acetabular dysplasia were assessed. All 127 patients treated for NHI from 1995 to 2001 at the study hospital and meeting the inclusion criteria were invited to participate in this population-based follow-up. Of these individuals, 88 (69.3%) participated. The lateral center-edge angle (LCEA), Sharp's angle (SA), and acetabular head index (AHI) were calculated for both hips from pelvic anterior-posterior radiographs. The Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire was completed for both hips separately; the total score, pain, and QOL subscores were calculated; and the impingement test was performed. The prevalence of acetabular dysplasia, defined as an LCEA <20°, was 3.4%. Only the mean AHI (81.1%, SD 5.3) differed (-5.08, 95% CI -5.77 to -4.38, P <0.001) from previously described gender-specific and side-specific means, whereas the mean LCEA and SA did not. The odds ratio for a positive hip impingement test was 2.8 (95% CI: 1.11-7.05, P = 0.029) for hips with an LCEA <25° compared to hips with LCEA ≥25°. The hips with an SA ≥45° had a mean of 7.8 points lower for the HAGOS pain subscore (95% CI: 4.2-11.4, P <0.001) and a mean of 6.1 points lower for the HAGOS QOL subscore (95% CI: 2.1-10.2, P = 0.003) compared with hips with an SA <45°. The prevalence of acetabular dysplasia was low after treatment for NHI. Acetabular dysplasia seems to be as common in the general population as for those treated for NHI based on the LCEA. Only an SA ≥45° resulted in slightly more pain and lower hip-related QOL.

The Windshield Wiper Sign Is an Instability-Related Osteochondral Defect of the Anterolateral Femoral Head

PurposeTo investigate a radiographic sign believed to be indicative of hip instability and acetabular suction seal disruption in the native hip, coined the “windshield wiper” (WSW) sign. Materials and MethodsA retrospective review was performed for patients who underwent periacetabular osteotomy (PAO) with the senior author between March 2021 and September 2023. A WSW sign was identified on plain films as a concave or flat osteochondral defect on the anterolateral femoral head extending medial to the head-neck junction with resultant loss of femoral head sphericity in the native hip. Every patient underwent a standardized series of radiographs, as well as computed tomography and magnetic resonance imaging. All patients underwent arthroscopy prior to PAO to address intra-articular pathology and other indicated procedures. The osteochondral defect and resultant suction seal disruption were verified during arthroscopy. These patients were then compared with a control group of arthroscopically treated hips without hip instability. ResultsOf 250 patients reviewed, a total of 19 hips in 17 patients (prevalence of 7.6%) demonstrated radiographic evidence of the WSW sign. All patients with a WSW sign presented with symptomatic clinical hip instability requiring a PAO. The mean patient age was 31.2 years, with a mean lateral center edge angle (LCEA) of 14.3 degrees. There were 13 hips (68.4%) with dysplasia, 4 (21.1%) with borderline dysplasia, and 2 (10.5%) with a normal LCEA. All patients with a WSW sign and LCEA ≥20° displayed significant femoral antetorsion abnormalities. All arthroscopic videos and images demonstrated a compromised suction seal. Of the 50 control group hips reviewed, the WSW sign was not identified. ConclusionsThe WSW sign is an uncommon radiographic finding in patients with hip instability. When identified, it can be predictive of substantial instability, especially in cases which are otherwise considered borderline dysplasia or normal based on LCEA. Level of EvidenceIII, case-control study

Poster 232: Clinical Outcomes Among Individuals with Global Acetabular Retroversion who Underwent Hip Arthroscopy for FAI with Minimum 5-Year Follow-Up

Objectives: The purpose of this study was to compare functional outcomes and clinical threshold achievement rates of patients with radiographic signs of global acetabular retroversion who underwent hip arthroscopy for FAI with minimum follow-up of 5 years. Methods: Patients were identified from a single-surgeon prospectively-collected database who underwent primary hip arthroscopy for treatment of FAI. Patients completed patient-reported outcome (PRO) surveys at both baseline and at 5-year follow-up. Demographic data was collected including age, sex, BMI at time of surgery, and patient-reported symptom length. Intraoperative findings were recorded, including the Outerbridge grade, presence of labral tears, chondral delamination, subspine impingement, cam lesions, pincer lesions, and mixed-type FAI. Global acetabular retroversion was assessed on AP view using three radiographic signs: ischial spine, posterior wall, and crossover signs. Other radiographic measures included alpha angle measured on three view (AP, 45° Dunn, 90° Dunn), lateral center edge angle (LCEA), and Tönnis grade. Results: We identified 124 primary hip arthroscopy patients who had minimum 5-year follow-up with adequate imaging and complete 5-year PROs. Preoperative X-rays demonstrated presence of ischial spine sign in 65 patients (52.4%), posterior wall sign in 61 patients (49.2%), and crossover sign in 75 patients (60.5%). Mean alpha angle was highest on AP view (62.2°), followed by 45° Dunn view (55.9°) and 90° Dunn view (50.9°) and mean LCEA was 38.5°. A baseline comparison demonstrated no significant differences between groups in age, sex, BMI, preoperative symptom length, Tönnis grade, Outerbridge grade, and preoperative mHHS or NAHS (p&gt;0.05). At 5-year follow-up, patients reported significant improvement in both mHHS (mean 50.4 to 82.7, p&lt;0.001) and NAHS (49.4 to 85.5, p&lt;0.001). Achievement rates were high for MCID (90.3%), SCB (80.7%), and PASS (79.0%) for the mHHS. Three-way frequency comparison of acetabular retroversion signs found that all three signs tended to be present together (40 patients, 32.3%) or absent together (31 patients, 25.0%). Pairwise comparisons with tetrachoric correlation testing found all three signs to be significantly correlated with one another: ischial spine sign versus posterior wall (rtet=0.65, corrected p&lt;0.001), ischial spine sign versus crossover sign (rtet=0.74, corrected p&lt;0.001), and posterior wall sign versus crossover sign (rtet=0.51, corrected p&lt;0.001). Multivariable analysis did not find any of the three signs to be significant independent predictors of 5-year improvement in mHHS or NAHS (p&gt;0.05). Posterior wall sign was associated with lower odds of achieving the MCID (OR = 0.62, 95% CI [0.06 to 1.09]) but this did not achieve significance (χ2=3.39, p=0.07). Overall, achievement rates for MCID, SCB, and PASS did not significantly differ between the cohorts with respect to each sign (p&gt;0.05). Conclusions: Clinical outcomes and achievement rates at 5-year follow-up demonstrated no significant differences among patients with respect to each sign of acetabular retroversion based on mHHS, NAHS, MCID, SCB and PASS. Surgeons should be reassured that these patients regain function at a rate similar to the greater FAI population.

Combining Shelf Osteotomy With Proximal Femoral Reconstruction After Oncologic Resection

Introduction: Oncologic proximal femoral resection and reconstruction in skeletally immature children remains a formidable task due to the risk of developing hip instability with patient growth or interval leg lengthening through the prosthesis. Shelf pelvic osteotomy increases femoral head coverage and containment, and favorable long-term results have been reported in the setting of developmental dysplasia of the hip and Perthes disease. We present a technique of combining shelf osteotomy with expandable proximal femoral endoprosthesis reconstruction in pediatric limb-sparing surgery. Materials and Methods: Four surgeons at 2 centers from 2012 to 2020 performed proximal femoral reconstruction with shelf osteotomy. Data were collected retrospectively on operative technique, radiographic measurements, and complications including dislocation, subluxation, implant loosening, pain, function, and radiographic outcomes. Results: Five patients were included in the study. The mean follow-up was 49 months (range: 17 to 104 mo). The mean lateral center edge angle status postproximal femoral resection and reconstruction shelf osteotomy was 56.1 degrees (±30.5). There were no reported incidences of subluxations, dislocations, periprosthetic fractures, or soft tissue complications. The 3 patients with the longest follow-up at 3, 5, and 8 years tolerated serial lengthening of the endoprosthesis totaling 1 cm, 7.25 cm, and 9 cm, respectively, and demonstrated earlier triradiate cartilage closure in the operative side compared with the nonoperative side. All patients have returned to independent ambulation. Discussion: Combining proximal femoral reconstruction with shelf osteotomy in limb salvage pediatric orthopedic oncology may help to improve hip stability with serial lengthening and patient growth.

Is There an Association Between Femoral Head Collapse and Acetabular Coverage in Patients With Osteonecrosis?

Osteonecrosis of the femoral head (ONFH) classification systems are based on the size, volume, and location of necrotic lesions. Often-but not always-ONFH results in femoral head collapse. Because acetabular coverage is associated with mechanical stress on the femoral head, it might also be associated with femoral head collapse in patients with ONFH. However, the association between acetabular coverage and femoral head collapse in these patients has not been established. (1) Is femoral head collapse associated with acetabular coverage or pelvic incidence (PI) in patients with ONFH? (2) Are established predictors of femoral head collapse in ONFH classification systems associated with acetabular coverage? Between 2008 and 2018, we evaluated 343 hips in 218 patients with ONFH. We considered all patients with ONFH except for those with a traumatic etiology, a history of surgical treatment before collapse, or those with collapse at initial presentation as potentially eligible for this study. Of those, 101 hips with ONFH (50% [50] were in males with a mean age of 44 ± 15 years) met our inclusion criteria. These patients were subsequently divided into two groups: those with femoral head collapse within 12 months (collapse group, 35 hips) and those without femoral head collapse (noncollapse group, 66 hips). No differences in patient demographics were observed between the two groups. CT images were used to measure the PI and acetabular coverage in three planes: the lateral center-edge angle (LCEA) in the coronal plane, the anterior and posterior center-edge angle in the sagittal plane, and the anterior and posterior acetabular sector angle in the axial plane; in addition, the difference between these parameters was investigated between the groups. The thresholds for femoral head collapse in the parameters that showed differences were investigated. Necrotic location and size were evaluated using the Japanese Investigation Committee (JIC) classification and the Steinberg grade classification, respectively. We examined the relationship between these parameters and classifications. The mean LCEA was slightly greater in the noncollapse group than in the collapse group (32° ± 6° versus 28° ± 7°; mean difference 4° [95% CI 1.15° to 6.46°]; p = 0.005); the clinical importance of this small difference is uncertain. There were no differences in PI between the two groups. After accounting for sex, age, BMI, and etiology as confounding factors, as well as acetabular coverage parameters and PI, we found a lower LCEA to be independently associated with increased odds of collapse, although the effect size is small and of questionable importance (OR 1.18 [95% CI 1.06 to 1.33]; p = 0.001). The threshold of LCEA for femoral head collapse was 28° (sensitivity = 0.79, specificity = 0.60, area under the curve = 0.73). The percentage of patients with an LCEA less than 28° was larger in JIC Type C1 (OR 6.52 [95% CI 1.64 to 43.83]; p = 0.006) and C2 (OR 9.84 [95% CI 2.34 to 68.38]; p = 0.001) than in patients with both Type A and Type B. The acetabular coverage data for the excluded patients did not differ from those of the patients included in the analysis. Our findings suggest that acetabular coverage appears to have little, if any, association with the likelihood of collapse in patients with ONFH. We found a small association between a lower LCEA and a higher odds of collapse, but the effect size may not be clinically important. Factors other than acetabular coverage need to be considered, and if our findings are verified by other investigators, osteotomy is unlikely to have a protective role. As the patients in our study were fairly homogeneous in terms of ethnicity and BMI, these factors need to be further investigated to determine whether they are associated with femoral head collapse in ONFH. Level III, prognostic study.

Periacetabular osteotomy: A novel application of modified Stoppa approach.

Background: The Bernese periacetabular osteotomy (PAO) is a well-established procedure for symptomatic hip dysplasia in adolescents and young adults. However, it remains a technically demanding procedure, and several major complications have been described, many of which are related to the approach and surgical exposure. The current study evaluates the efficacy and safety of PAO performed through a modified Stoppa approach. Methods: A prospective series of nine consecutive patients with hip dysplasia were treated PAO through the modified Stoppa approach. The mean age was 22.4 years (15–30 years) and the mean follow-up was 3.2 years (2–5 years). Harris hip score (HHS) was used as a functional score, and the radiographic indices included the lateral center-edge angle (LCEA) and Tönnis roof angle. Results: The approach allowed the osteotomy lines to be performed under direct visualization from the intra-pelvic surface of the acetabulum, aided by fluoroscopy. A lateral window was added to perform the final iliac cut and for subsequent mobilization and fixation of the acetabular fragment. The mean HHS improved significantly from 70.8 ± 4.9 points to 90.1 ± 3.3 points (p < 0.001). The mean LCEA improved from 8.2° ± 4.9 (range: 0–14) to 32.7° ± 5.3 (range: 26–40), with a mean improvement of 24.5°. The mean Tönnis angle improved from 28.4° ± 4.4 (range: 22–35) to 3.8° ± 3.3 (range: 0–10). Two patients had irritation from prominent screw heads that necessitated removal 1 year after the index procedure. One patient had radiographic progression of osteoarthritis. No cases of infection, non-union, heterotopic ossification, or nerve palsy were identified till the latest follow-up. Conclusion: Ganz PAO can be safely conducted through the modified Stoppa approach, providing direct exposure to the osteotomized surfaces, and protecting susceptible neuro-vascular structures.Level of evidence: IV.

Nonarthritic Hip Pathology Patterns According to Sex, Femoroacetabular Impingement Morphology, and Generalized Ligamentous Laxity

Background: Sex differences are frequently encountered when diagnosing orthopaedic problems. Current literature suggests specific sex differences, such as a higher prevalence of cam-type femoroacetabular impingement syndrome in male patients and features of hip instability in female patients. Purpose: To identify hip pathology patterns according to sex, alpha angle deformity, and generalized ligamentous laxity (GLL) in a nonarthritic patient population that underwent primary hip arthroscopy in the setting of femoroacetabular impingement syndrome and labral tears. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients who underwent primary hip arthroscopy between February 2008 and February 2017 were included and separated into male and female groups for initial analysis. Patients were excluded if they had Tönnis osteoarthritis grade >1, previous ipsilateral hip surgery, or previous hip conditions. The demographics, radiographic findings, intraoperative findings, and surgical procedures were then analyzed and compared. Subanalyses were performed for both groups. A threshold of 1 SD above the mean alpha angle in the male group was used to create 2 subgroups. For female patients, GLL based on a Beighton score ≥4 was used to divide the group. Intraoperative findings were compared for both subanalyses. Results: A total of 2701 hips met all inclusion and exclusion criteria. Of those, 994 hips were in the male group and 1707 in the female group. The mean ± SD age was 36.6 ± 13.8 and 37.1 ± 15.0 years for the male and female groups, respectively(P = .6288). The average body mass index was significantly higher in the male group (P < .0001). GLL was more common in women (38.6%) than men (13.6%) (P < .001). The male group had a higher proportion of acetabular Outerbridge grade 3 (21.8%) and 4 (19.2%) lesions when compared with the female group (9.3% and 6.3%, respectively) (P < .0001). Men in the subgroup with an alpha angle ≥78° reported higher rates of acetabular Outerbridge grade 4 damage than men with an alpha angle <78° (P < .001). Mean lateral center-edge angle was lower in the female subgroup with Beighton score ≥4 vs <4 (23.7°± 4.2° vs 31.3°± 5.8°; P < .0001). Conclusion: In this analysis of a large cohort of patients who underwent hip arthroscopy, 2 patterns of hip pathologies were related to sex. On average, male patients had larger alpha angles and increased acetabular chondral damage when compared with their female counterparts. Furthermore, a larger cam-type anatomy was associated with more severe acetabular chondral damage in men. In the female group, the incidence of features of hip instability such as GLL were significantly higher than in the male group.

Cementless Hip Arthroplasty in Patients with Subchondral Insufficiency Fracture of the Femoral Head.

Subchondral insufficiency fracture of the femoral head (SIFFH) occurs in elderly patients and might be confused with osteonecrosis of the femoral head (ONFH). Subchondral insufficiency fracture of the femoral head is an insufficiency fracture at the dome of the femoral head and has been known to be associated with osteoporosis, hip dysplasia, and posterior pelvic tilt. This study's aims were to evaluate (1) surgical complications, (2) radiological changes, (3) clinical results, and (4) survivorship of THA in patients with SIFFH. From November 2010 to June 2017, 21 patients (23 hips); 5 men (5 hips) and 16 women (18 hips) underwent cementless THA due to SIFFH at our institution. Their mean age was 71.9 years (range, 57 to 86) at the time of surgery, and mean T-score was -2.2 (range, -4.2 to 0.2). The mean lateral center-edge angle, abduction, and anteversion of the acetabulum were 29.9° (range, 14.8° to 47.5°), 38.5° (range, 31° to 45°), and 20.0° (range, 12° to 25°), respectively. The mean pelvic incidence, lumbar kyphotic angle and posterior pelvic tilt were 56.4° (range, 39° to 79°), 14.7° (range, -34° to 43°), and 13.0° (range, 3° to 34°), respectively. An intraoperative calcar crack occurred in 1 hip. The mean anteversion and abduction of cup were 29.0° (range, 17° to 43°) and 43.3° (range, 37° to 50°), respectively. One patient sustained a traumatic posterior hip dislocation 2 weeks after the procedure, and was treated with open reduction. At a mean follow-up of 35.4 months (range, 24 to 79 months), no hip had prosthetic loosening or focal osteolysis. At the latest follow-up, the mean modified Harris hip score was 79.1 (range, 60 to 100) points, and mean UCLA activity score was 4.2 (range, 2 to 7) points. The survivorship was 95.7% (95% CI, 94.9% to 100%) at 6 years. Cementless THA is a favorable treatment option for SIFFH in elderly patients. 3.

Endoscopic Shelf Acetabuloplasty Concomitant With Labral Repair, Cam Osteoplasty, and Capsular Plication to Treat Acetabular Dysplasia in Artistic Athletes: A Case Series.

Background:Knowledge of clinical outcomes and return to artistic activities after endoscopic shelf acetabuloplasty (ESA) for acetabular dysplasia in artistic athletes is lacking.Hypothesis:Hip arthroscopic surgery including ESA will enable artistic athletes to return to their activities with a high success rate, significantly improved acetabular coverage, and preserved joint cartilage.Study Design:Case series; Level of evidence, 4.Methods:We reviewed 28 hips in 23 female artistic athletes (14 ballet, 9 rhythmic gymnastics, 4 dance, and 1 baton twirling) who underwent arthroscopic labral preservation, capsular plication, and ESA. Their mean age was 25.8 ± 10.2 years. Preoperatively, all patients had generalized joint laxity (Beighton score, 7.1 ± 1.8). We evaluated preoperative and postoperative radiographs and outcome scores including the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), International Hip Outcome Tool 12 (iHOT-12), Vail Hip Score (VHS), and Hip Outcome Score–Sports (HOS— Sports). Statistical analysis was performed using paired t tests and Bonferroni correction.Results:The mean follow-up was 32.5 ± 12.5 months. The mean lateral center-edge angle significantly increased from preoperatively (15.7° ± 5.3°) to postoperatively (39.8° ± 8.2°; P < .001) and at the final follow-up (33.7° ± 8.6°; P < .001). The vertical-center-anterior angle significantly improved from preoperatively (16.2° ± 8.8°) to final follow-up (33.6° ± 8.0°; P < .001). All hips maintained a Tönnis grade of 0 or 1 at the final follow-up. Overall, 20 patients (87%) were able to return to their preinjury level. All outcome scores improved from preoperatively to postoperatively: mHHS, from 68.5 ± 18.1 to 88.3 ± 18.5; NAHS, from 50.8 ± 17.7 to 69.0 ± 11.4; iHOT-12, from 36.9 ± 19.3 to 75.2 ± 19.8; VHS, from 53.8 ± 13.7 to 79.4 ± 19.4; and HOS--Sports, from 59.9 ± 17.0 to 79.6 ± 21.3 (P < .001 for all). In total, 3 patients could not return to artistic activities as the result of postoperative deep gluteal syndrome.Conclusion:ESA concomitant with labral repair, cam osteoplasty, and capsular plication to treat dysplastic hips in patients with joint laxity enabled artistic athletes to return to their activities with a high success rate.

Arthroscopic Treatment of Labral Tears in Patients with Borderline Developmental Dysplasia of the Hip: A Retrospective Study with Mean 5.8 Years Follow-Up.

ObjectiveTo retrospectively assess the mid‐term clinical and radiological results of hip arthroscopic treatment of labral tears in patients with borderline developmental dysplasia of the hip (BDDH).MethodsFrom January 2010 and December 2019, data were retrospectively reviewed for all patients who underwent arthroscopic surgery of the hip for the treatment of intra‐articular abnormalities. Only the Patients who had borderline developmental dysplasia (BDDH) were included. All operations were performed by two senior surgeons, the arthroscopic treatment including labral repair, labral debridement, minimal acetabuloplasty, femoroplasty and capsular closure. The evaluation consisted of pain evaluation (visual analog scale [VAS]), the modified Harris hip score (MHHS), range of motion, the radiological evaluation of plain film and MRI analysis of the hip joint. The plain film evaluation included anteroposterior views of the pelvis to assess lateral center‐edge angle (LCEA) and acetabular inclination (AI), frog‐leg lateral views of the hip to assess α angle.ResultsThere were 34 patients (36 hips) ultimately enrolled in this study. The follow‐up duration of the patients were minimal 2 years (average, 69.2 months) postoperatively. The patient group included seven men and 27 women, the mean age at the time of surgery was 30.9 years. The mean BMI was 22.3 kg/m2. From the pre‐operative status to the final follow‐up visit, mean mHHS score increased from 64.5 to 92.7, mean VAS score decreased from 6.8 to 1.3. All scores exhibited statistically significant differences (P < 0.001). The mean LCEA decreased from 22.9° to 22.7°, the mean AI decreased from 7.7° to 7.6°. Which all showed no significant differences compared with the final follow‐up to the pre‐operative status (P > 0.05). However, the mean α angle was significantly decreased from 48.3° to 40.1° (P < 0.001). We encountered no significant complications such as infection, deep venous thrombosis, fluid extravasation, or permanent nerve injury. One patient (2.94%) underwent revision periacetabular osteotomies (PAO) because of subluxation of the hip joint with permanent pain after 6 months failed conservative treatment.ConclusionArthroscopic treatment of labral tears in patients with BDDH may provide safe and durable favorable results at midterm follow‐up. The best outcome could be expected in patients with labral repair and closure of the capsule with strict patient selection criteria.

Hip dysplasia is not uncommon but frequently overlooked: a cross-sectional study based on radiographic examination of 1,870 adults

Background and purpose — Hip dysplasia in adults is a deformity in which the acetabulum inadequately covers the femoral head. The prevalence is sparingly described in the literature. We investigated the prevalence in Malmö (Sweden) and assessed whether the condition was recognized in the radiology reports. Subjects and methods — All pelvic radiographs performed in Malmö during 2007–2008 on subjects aged 20–70 years with a Swedish personal identity number were assessed. 1,870 digital radiographs were eligible for analysis. The lateral center-edge angle (LCEA) and acetabular index angle (AIA) were measured. Hip dysplasia was defined as an LCEA ≤ 20°. Intraclass correlation coefficients (ICC) for intra-observer measurements ranged from 0.87 (AIA, 95% CI 0.78–0.93) to 0.98 (LCEA, CI 0.97–0.99). Results — The prevalence of hip dysplasia (LCEA ≤ 20°) was 5.2% (CI 4.3–6.3), (98/1,870). There was no statistically significant difference between the sexes for either prevalence of hip dysplasia or mean LCEA. The mean AIA was 0.9° (CI 0.3–1.3) higher in men (4.1 SD 5.5) compared with women (3.2 SD 5.4). The radiologists had reported hip dysplasia in 7 of the 98 cases. Interpretation — The prevalence of hip dysplasia in Malmö (Sweden) is similar to previously reported data from Copenhagen (Denmark) and Bergen (Norway). Our results indicate that hip dysplasia is often overlooked by radiologists, which may influence patient treatment.

Correlation of the Imaging Features of Femoroacetabular Impingement Syndrome With Clinical Findings and Patient Functional Scores.

The relationship among the severity of the imaging features of femoroacetabular impingement syndrome (FAIS), patient symptoms, and function has not been elucidated. Understanding this relationship helps to improve the prognostic value of imaging. The goal of this study was to examine the correlation of clinical findings, patient pain, and function with severity, as measured with radiographic and 3-dimensional magnetic resonance imaging (3D-MRI). Data collected prospectively through a longitudinally maintained hip database were reviewed, and 37 hips from 31 patients were included. All patients were examined by an experienced orthopedic surgeon, and preoperative radiographs and 3D-MRI were obtained. Preoperatively, the patients completed validated patient-reported outcome measures (PROMs). Mean±SD alpha angles were 69.4°±10.3°, 70.0°±10.3°, 70.6°±8.4°, and 74.8°±9.2° at 12 o'clock, 1 o'clock, 2 o'clock, and 3 o'clock, respectively. Mean lateral center edge angle was 30.1°±5.3°. The authors did not observe a statistically significant correlation between PROMs and the features measured by radiographs and 3D-MRI (P>.05). In this subset of prospectively imaged patients with FAIS, the authors did not find a correlation between the severity of symptoms measured by PROMs and features on radiographs and 3D-MRI. The severity of dysfunction is multifactorial, and anatomic severity, as measured radiographically and with 3D-MRI, may not correlate with symptoms. Further investigation is necessary to address the sources of patient pain. [Orthopedics. 2021;44(4):e577-e582.].

The Inverse Relationship Between Labral Size and Acetabular Coverage: Does It Protect the Cartilage in the Dysplastic Hip?

The aims of this study were to confirm the relationship between osseous coverage and labral size and toinvestigate the severity of intra-articular damage in borderline dysplastic hips in correlation to labral size. Patients treated with primary hip arthroscopy for symptomatic labral tears between 2010 and 2018 were considered for this study. Patients were included if they had preoperative radiographic measures and intraoperative assessments of the labra and cartilage. The study group was divided into borderline dysplastic and nondysplastic groups via 3 measurements: lateral center edge angle (LCEA), acetabular index (Ax), and anterior center edge angle (ACEA). Undercoverage was defined as LCEA ≤ 25°, Ax ≥ 10°, and ACEA ≤ 20°. The labrum was measured in four quadrants: anterosuperior (AS), anteroinferior (AI), posterosuperior (PS), and posteroinferior (PI). Additionally, to assess cartilage damage in borderline dysplastic hips, hips with average labral size in the top quartile were compared to hips with average labral size in the bottom quartile. A total of 1765 hips (1589 patients) were included in the study. The mean LCEA, Ax, and ACEA between the borderline dysplastic and nondysplastic groups were significantly different (P < .001). According to the Ax classification, there was significant evidence that borderline dysplastic hips had larger labra (P < .05). Among the dysplastic group, there was significantly more cartilage damage according to the Outerbridge classifications along both the acetabulum and femoral head in hips with labra in the upper quartile (P=.011 and .005, respectively). An inverse relationship may exist between acetabular depth and labral size. Additionally, specifically in borderline dysplastic hips, a relatively large labrum correlates with worse intra-articular damage compared to borderline dysplastic hips with a relatively small labrum. Larger labral size may indicate a higher degree of instability in patients with borderline dysplasia. Level III, case-control study.

Hip Morphology in Early-stage LCPD: Is There an Argument for Anatomic-specific Containment?

Early containment surgery has become increasingly popular in Legg-Calvé-Perthes Disease (LCPD), especially for older children. These procedures treat the proximal femur, the acetabulum, or both, and most surgeons endorse the same surgical option regardless of an individual patient's anatomy. This "one-surgery-fits-all" approach fails to consider potential variations in baseline anatomy that may make one option more sensible than another. We sought to describe hip morphology in a large series of children with newly diagnosed LCPD, hypothesizing that variation in anatomy may support the concept of anatomic-specific containment. A retrospective review of a prospectively collected multicenter database was conducted for patients aged 6 to 11 at diagnosis. To assess anatomy before significant morphologic changes secondary to the disease itself, only patients in Waldenström stages IA/IB were included. Standard hip radiographic measurements including acetabular index, lateral center-edge angle, proximal femoral neck-shaft angle (NSA), articulotrochanteric quartiles, and extrusion index (EI) were made on printed anteroposterior pelvis radiographs. Age-specific percentiles were calculated for these measures using published norms. Significant outliers (≤10th/≥90th percentile) were reported where applicable. A total of 168 patients with mean age at diagnosis of 8.0±1.3 years met inclusion criteria (81.5% male). Mean acetabular index for the entire cohort was 16.8±4.1 degrees; 58 hips (34.5%) were significantly dysplastic compared with normative data. Mean lateral center-edge angle was 15.9±5.2 degrees at diagnosis; 110 (65.5%) were ≤10th percentile indicating dysplasia (by this metric). Mean NSA overall was 136.5±7.0 degrees. Fifty-one (30.4%) and 20 (11.9%) hips were significantly varus (≤10th percentile) or valgus (≥90th percentile), respectively. Thirty-five hips (20.8%) were the third articulo-trochanteric quartiles or higher suggesting a higher-riding trochanter at baseline. Mean EI was 15.5%±9.0%, while 63 patients (37.5%) had an EI ≥20%. The present study finds significant variation in baseline anatomy in children with early-stage LCPD, including a high prevalence of coexisting acetabular dysplasia as well as high/low NSAs. These variations suggest that the "one-surgery-fits-all" approach may lack specificity for a particular patient; a potentially wiser option may be an anatomic-specific containment operation (eg, acetabular-sided osteotomy for coexisting dysplasia, varus femoral osteotomy for valgus NSA). Level IV.

The lateral center-edge angle as radiographic selection criteria for periacetabular osteotomy for developmental dysplasia of the hip in patients aged above 13 years

BackgroundThis retrospective study sought to delineate the radiographic characteristics of DDH patients over 13 years of age and investigate whether the lateral center-edge angle (LCEA) could serve as radiographic selection criteria for periacetabular osteotomy.MethodsWe enrolled patients with Hartofilakidis type I DDH without dislocation who underwent periacetabular osteotomy between August 2009 and August 2012. LCEA, anterior central edge angle (ACEA), femoral neck-shaft angle (FNSA), Shenton line and Tönnis acetabular index (AI) were evaluated by anteroposterior and 65° false⁃profile pelvic X-ray radiographs in the standing position. Femoral neck anteversion angle (FNA), labral lesion, labral inversion and cartilage lesion were evaluated by direct magnetic resonance arthrography. DDH was categorized by LCEA into four grades (grade I: 10° ≤ LCEA< 20°, grade II: 0° ≤ LCEA< 10°, grade III: -10° ≤ LCEA< 0°, grade IV: LCEA<-10) and osteoarthritis (OA) severity was assessed using Tönnis OA classification. Pearson correlation analysis was done between LCEA and other variables.ResultsTotally patients (274 hips) with a mean age of 27.3 years (range 13–47 years) were included. The mean LCEA was 3.5° (range: − 30° to 20°). Based on LCEA grades, grade I DDH was present in 104 hips, grade II in 40 hips, grade III in 76 hips, and grade IV in 54 hips. Based on Tönnis OA classification, 54.5% hips (150/274) were grade 0, 33.1% hips (91/274) grade 1, 8.4% hips (23/274) grade 2 and 4% hips (11/274) grade 3. Pearson correlation analysis showed a negative correlation between LCEA grade and Tönnis OA grades (r = 0.3987; P < 0.001). Cochran-Armitage trend test further showed a positive correlation between LCEA grades and labral lesion (P < 0.001) and interrupted Shenton line (P < 0.001).ConclusionThe LCEA classification scheme offers a simple and practical approach to categorize the level of acetabulum coverage on the femoral head, hip deformity and characteristics of DDH. Our findings could provide clinically useful guidance for orthopedic surgeons in preparation for periacetabular osteotomy in DDH patients aged above 13 years.

Defining the Borderline Hip: High Variability in Acetabular Coverage and Femoral Deformity

Objectives:Borderline acetabular dysplasia is radiographically defined as a lateral center edge angle (LCEA) of 20-25 degrees. It is well accepted that some borderline hips have instability while others have primarily impingement. The optimal management of borderline dysplasia is challenging and particularly complex due to the anatomic variability that exists among patients but has not been well characterized. The purpose of this current study was to investigate the variability in hip deformity present on low-dose CT in a cohort of patients with symptomatic borderline acetabular dysplasia.Methods:Seventy consecutive hips with borderline acetabular dysplasia undergoing surgical treatment were included in the current study. Radiographic evaluation included LCEA, acetabular inclination, anterior center edge angle (ACEA), and alpha angles on AP, Dunn, and frog views. All patients underwent low-dose pelvic CT for preoperative planning. Femoral deformity was assessed with femoral version, alpha angle (measured at 1:00 increments), and maximum alpha angle. Radial acetabular coverage was calculated according to standardized clockface positions [measured from 8:00 (posterior) to 4:00 (anterior)] and defined as normal, undercoverage, or overcoverage relative to 1 SD from the mean of normative values.Results:The mean LCEA was 22.1+1.4, while the mean acetabular inclination was 10.3+3.3. The mean ACEA in the group was 25.3+5.8 (range 10.1-43.9), with 16% having an ACEA < 20 and 50% having an ACEA < 25. The mean femoral version was 17.9° (range -4° to 59°). The mean maximal alpha angle was 57.2° (range 43° to 81°) with 61.4% greater than 55°. Lateral coverage (RAC at 12:00) was deficient in 74.1% of cases. Anterior coverage (RAC at 2:00) was highly variable with 17.1% undercoverage, 72.9% normal, and 10.0% overcoverage. Posterior coverage (RAC at 10:00) was also highly variable with 30.0% undercoverage, 62.9% normal, and 7.1% overcoverage. The three most common patterns of coverage were: isolated lateral undercoverage (31.4%), normal coverage (18.6%), and lateral and posterior undercoverage (17.1%).Conclusion:Patients with borderline acetabular dysplasia demonstrate highly variable three-dimensional deformities including anterior, lateral, and posterior acetabular coverage, femoral version, and alpha angle. Comprehensive deformity characterization in the population is important to guide diagnosis and treatment decisions.Figure 1.Figure 2.Figure 3.

Borderline Dysplasia with Acetabular Retroversion: Key Findings from a Large Hip Arthroscopy Study Group

Objectives:The radiographic crossover sign (COS) is an indicator of acetabular retroversion, classically representing anterosuperior overcoverage often treated with acetabuloplasty which could exacerbate acetabular hypovolemia in dysplasia. No prior study has investigated the prevalence of acetabular retroversion in patients with dysplasia undergoing hip arthroscopy, acetabuloplasty rates, and outcomes in this setting.Study objectives are to report the prevalence of acetabular retroversion in dysplasia, the influence of the COS on arthroscopic acetabuloplasty rates, and relative outcomes compared with control groups.Methods:A retrospective cohort study was performed from a prospectively collected multi-center database. Patients undergoing isolated hip arthroscopic surgery were assigned to dysplasia (lateral center-edge angle (LCEA) ≤ 25°) or one of two control groups: normal(LCEA 26-38°), or pincer femoroacetabular impingement (FAI)(LCEA ≥ 39°). The prevalence of COS and acetabuloplasty rates between and within study and control groups were compared (Chi square analysis). Minimum 2 year outcomes utilizing iHOT-12 were compared (analysis of variance).Results:Of 401 study patients, 64 (16%) comprised the dysplasia group, 273 (68%) normal group, and 64 (16%) pincer group. Mean LCEAs were 22.3°, 31.5°, and 42.4°, respectively (p<0.001). COS prevalence was similar between groups at 31%, 26%, and 33%, respectively (p=0.873). Acetabuloplasty rates were dependent on the amount of acetabular coverage with lowered rate in the dysplasia group(40%) and increasing rates in the normal(52%) and the pincer(90%) groups (p=0.013). Post-operative iHOT-12 scores improved in all groups (68, 74, and 77, respectively, p=0.222). Patients with a COS plus rendered acetabuloplasty reported similar scores that improved to 77, 74, and 79, respectively,(p=0.949). Patients with dysplasia with COS averaged 73.1(SD 23.3) iHOT-12 score compared to 67.1(SD: 28.7) for the patients with dysplasia without COS (p=0.466). Within the dysplasia with COS subgroup, there was no significant difference in iHOT-12 scores between the group with acetabuloplasty (77.0;SD:17.1) and without acetabuloplasty (70.4;SD:27.4,p=0.580).Conclusion:Acetabular retroversion occurs with similar prevalence in borderline dysplasia compared with non-dysplastic hips undergoing hip arthroscopy but with lower acetabuloplasty rates not influenced by the COS. Arthroscopic outcomes of dysplasia with retroversion are similarly successful and comparable with those of dysplasia and non-dysplastic hips. Although infrequently performed, acetabuloplasty did not compromise outcomes in dysplasia with retroversion.