Do Patients With Borderline Dysplasia Have Inferior Outcomes After Hip Arthroscopic Surgery for Femoroacetabular Impingement Compared With Patients With Normal Acetabular Coverage?

BACKGROUND: The literature contains conflicting reports regarding whether outcomes of hip arthroscopic surgery for patients with borderline dysplasia are inferior to outcomes in patients with normal acetabular coverage.

PURPOSE: To assess differences in the outcomes of hip arthroscopic surgery for femoroacetabular impingement (FAI) in groups of patients with borderline dysplasia and normal coverage.

STUDY DESIGN: Cohort study; Level of evidence, 3.

METHODS: A registry of consecutive patients who had undergone primary hip arthroscopic surgery with capsular plication for FAI between January 2012 and January 2014 were divided based on the preoperative lateral center-edge angle (LCEA) into 2 distinct groups: (1) borderline dysplasia (LCEA 18°-25°) and (2) normal acetabular coverage (LCEA 25.1°-40°). There were 36 patients in the borderline dysplastic group and 312 patients in the normal coverage group. The primary outcome measure was the Hip Outcome Score-Activities of Daily Living (HOS-ADL) at a minimum of 2 years postoperatively. Secondary outcome measures included the HOS-Sports and modified Harris Hip Score (mHHS).

RESULTS: The mean preoperative LCEA differed significantly between groups (23.4° ± 1.5° for borderline dysplastic, 32.5° ± 3.8° for normal coverage; P < .001). The borderline dysplastic group had a higher percentage of female patients than the normal coverage group (27/36 [75%] vs 177/312 [57%], respectively; P = .048). There were no differences in other preoperative demographics and radiographic parameters. At a minimum 2 years after hip arthroscopic surgery (mean follow-up, 2.6 ± 0.6 years), both groups demonstrated significant improvements in all patient-reported outcome scores ( P < .001 in all cases). There were no significant differences between the borderline dysplastic and normal coverage groups in final outcome scores, score improvements, or percentage of patients experiencing clinically significant improvements. One patient in the borderline dysplastic group (3%) underwent revision hip arthroscopic surgery, and none underwent total hip arthroplasty during the follow-up period. There were no differences between the borderline dysplastic and normal coverage groups with regard to subsequent surgery. Female patients in the borderline dysplastic group had greater improvements in the mean HOS-ADL (25.9 ± 16.3 vs 10.8 ± 18.5, respectively; P = .05) and mHHS (27.9 ± 12.9 vs 8.1 ± 19.0, respectively; P = .005) compared with male patients in the borderline dysplastic group, but male and female patients did not differ in outcomes for the normal coverage group.

CONCLUSION: Patients who underwent hip arthroscopic surgery for FAI with capsular plication experienced significant clinical improvements with low rates of subsequent surgery, regardless of whether their acetabulum had borderline dysplasia or normal coverage.