Hip Arthroscopic Surgery in the Context of Femoroacetabular Impingement Syndrome, Labral Tear, and Acetabular Overcoverage: Minimum 5-Year Outcomes With a Subanalysis Against Patients Without Overcoverage

Background: Improvement in patient-reported outcomes (PROs) has been reported in the short term after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and labral tear in the setting of acetabular overcoverage. Yet, there is a paucity of information in the literature on midterm PROs. Purpose: To (1) report minimum 5-year PROs in patients who underwent primary hip arthroscopy for FAIS and acetabular labral tears in the context of acetabular overcoverage and (2) compare outcomes with those of a propensity-matched control group without acetabular overcoverage. Study Design: Cohort study; Level of evidence, 3. Methods: Data were prospectively collected and retrospectively analyzed on all patients who underwent hip arthroscopy for FAIS and labral tears between February 2008 and November 2013. Inclusion criteria were lateral center-edge angle >40° and minimum 5-year follow-up for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and the Hip Outcome Score–Sports-Specific Subscale (HOS-SSS). Exclusion criteria were previous ipsilateral hip surgery or conditions, active workers’ compensation claims, or lack of minimum 5-year outcomes. A 1:1 propensity-matched comparison was made between the study group and a control group without acetabular overcoverage (lateral center-edge angle, 25°-40°) based on age at surgery, sex, body mass index, Tönnis grade, laterality, and follow-up time. The minimal clinically important difference (MCID) was calculated for the mHHS, HOS-SSS, and NAHS. Secondary surgical procedures were recorded. Results: A total of 54 patients satisfied the inclusion criteria for the study group, of whom 45 (83.3%; 45 hips) had a minimum 5-year follow-up and were matched without differences in age at surgery, sex, body mass index, or follow-up time. The study and control groups demonstrated significant and comparable improvements for the mHHS (mean ± SD Δ, 24.06 ± 24.19 vs 26.33 ± 17.27; P = .625), NAHS (Δ, 31.22 ± 25.31 vs 27.15 ± 17.61; P = .399), and HOS-SSS (Δ, 33.16 ± 34.73 vs 34.75 ± 26.15; P = .557). The rates for achieving the MCID were similar for the study and control groups for the mHHS (76.7% vs 84.2%; P = .399), HOS-SSS (79.1% vs 75.8%; P = .731), and NAHS (81.4% vs 84.2%; P = .738). Need for revision surgery was similar ( P = .748). A lower conversion rate to total hip arthroplasty was reported for the study than for the control group (2.2% vs 15.6%; P = .026). Conclusion: In the context of FAIS, labral tears, and acetabular overcoverage, patients who underwent hip arthroscopy reported significant improvement in several PROs at minimum 5-year follow-up. Moreover, outcomes were comparable with those of a propensity-matched control group without acetabular overcoverage. Furthermore, the rate of achieving the MCID for the mHHS, HOS-SSS, and NAHS was similar between these groups.

Importance of Retaining Sufficient Acetabular Depth: Successful 2-Year Outcomes of Hip Arthroscopy for Patients With Pincer Morphology as Compared With Matched Controls

Background: Patients with pincer-type femoroacetabular impingement are commonly treated with arthroscopic reduction of acetabular depth as measured by the lateral center-edge angle (LCEA). The optimal amount of rim reduction has not been established, although large resections may increase contact pressures through the hip. A recent publication demonstrated inferior surgical outcomes in patients with acetabular overcoverage as compared with normal acetabular coverage. Casual observation of our database suggested equivalent improvements, prompting a similar analysis. Purpose: To analyze patient-reported outcomes after hip arthroscopy for femoroacetabular impingement in patients with acetabular overcoverage who were matched with controls with normal coverage, as well as to analyze associations with reduction in LCEA. Study Design: Cohort study; Level of evidence, 3. Methods: Data were collected prospectively from patients with a minimum 2-year follow-up after receiving hip arthroscopy for femoroacetabular impingement by a single surgeon. Cases were reviewed to identify those with pincer-type morphology (LCEA >40°) and matched according to sex, age, chondral damage, and surgery date in a 1:1 ratio with controls with an LCEA of 25° to 40°. The surgical goal was to reduce the LCEA to the upper end of the normal range with minimal rim resection, usually 35° to 37°. Radiographic measurements of coverage, intraoperative findings, procedures, and patient-reported outcomes were recorded, including the 12-Item International Hip Outcome Tool, Non-arthritic Hip Score, Hip Disability and Osteoarthritis Outcome Score, visual analog scale for pain, rates of revision or reoperation, and conversion to total hip arthroplasty. Results: A total of 114 hips (93 patients) for the pincer group were matched 1:1 from 616 hips (541 patients) for the control group. The pincer group (mean ± SD age, 34.5 ± 12.2 years) did not differ in age, body mass index, or follow-up from controls. LCEA was reduced in both groups pre- to postoperatively: the pincer group from 44.0° ± 2.8° to 34.2° ± 3.5° and the controls from 32.9° ± 3.9° to 31.0° ± 3.0°. No differences in improvement were observed: iHOT-12 improved by 35.7 points in both groups ( P = .9 for analysis of variance interaction) and Nonarthritic Hip Score by 22.3 points ( P = .6). From all eligible surgical procedures, 2-year follow up rates were 2.5% and 2.6% for the pincer and control cohorts, respectively, and 1.2% and 0.3% for conversion to total hip arthroplasty. Conclusion: Arthroscopic management of acetabular overcoverage can achieve excellent results, equivalent to arthroscopy for other causes of symptomatic femoroacetabular impingement. A key finding was smaller rim resections producing a mean postoperative LCEA of 34.2° with a small standard deviation.

Across the Spectrum from Borderline Dysplasia to Global Pincer Femoroacetabular Impingement: Arthroscopic Outcomes from a Large Hip Arthroscopy Study Group

Objectives: Outcomes from hip arthroscopy for dysplasia and global pincer FAI have fallen short of those for patients with normal acetabular coverage, but no study has investigated arthroscopic outcomes across the spectrum of acetabular coverage. Our objective is to report comparative hip arthroscopic outcomes of patients with low (borderline dysplasia), normal, and high (global pincer FAI) lateral acetabular coverage. Methods: A retrospective analysis of prospectively-collected data from a large multi-center registry (seven United States centers) was performed. Primary hip arthroscopy patients were assigned to one of three groups based on preoperative lateral center-edge angle (LCEA): borderline dysplasia (≤25°), normal (26-38°), and pincer FAI (≥39°). Repeated measures ANOVA compared pre-operative to 2-year minimum post-operative iHOT-12 scores. Subsequent ANOVA determined the effect of acetabular coverage on magnitude of change in scores. Results: Of 437 patients, the only statistical difference between groups was lower prevalence of acetabuloplasty in the borderline dysplasia group (p=0.001). A significant improvement in the pre-operative to post-operative iHOT-12 scores for patients with normal acetabular coverage, acetabular undercoverage, and acetabular overcoverage was observed; F(1, 339)=311.06; p<0.001, with no statistical differences in pre-operative (p=0.505) and post-operative (p<0.488) iHOT-12 scores when comparing the groups based on acetabular coverage. Mean iHOT-12 scores increased from 37.3 pre-operatively to 68.7 postoperatively, p<0.001, in the borderline dysplasia group, from 34.4 to 72, p<0.001, in the normal coverage group, and from 35.3 to 69.4, p<0.001, in the pincer group. These pre-operative scores increased by 31.4, 37.8, and 34.1, respectively, with no effect for acetabular coverage on the magnitude of change from pre-operative to post-operative iHOT-12 scores, F(2,339) =1.18; p=0.310. 10 subjects (2.3%) underwent conversion arthroplasty and 19 patients (4.4%) underwent revision arthroscopy with no significant effect of acetabular coverage on the incidence of revision or conversion surgery, X2 (6,433)=11.535, P = 0.073. Conclusion: Lateral acetabular coverage did not influence outcomes from primary hip arthroscopy performed in patients with low (borderline dysplasia), normal, and high (global pincer FAI) LCEA. Borderline dysplasia and moderate global pincer FAI with no or minimal osteoarthritis do not compromise successful 2-year minimum outcomes or survivorship following primary hip arthroscopy when performed by experienced surgeons.

Subchondral Insufficiency Fracture of the Femoral Head Caused by Excessive Lateralization of the Acetabular Rim

We present a case of a 53-year-old woman with subchondral insufficiency fracture (SIF) of the femoral head without history of severe osteoporosis or overexertion. Plain radiographs showed acetabular overcoverage with excessive lateralization of the acetabular rim. A diagnosis of SIF was made by typical MRI findings of SIF. The lesion occurred at the antipodes of the extended rim. Increased mechanical stress over the femoral head due to impingement against the excess bone was suspected as a cause of SIF. The distinct femoral head deformity is consistent with this hypothesis. This is the first report of SIF associated with acetabular overcoverage.