Midterm Results of Surgical Hip Dislocation for the Treatment of Femoroacetabular Impingement

Abstract

Background: Surgical treatment of femoroacetabular impingement (FAI) includes both open and arthroscopic procedures. Encouraging results have been reported for the majority of patients after surgical hip dislocation; however, most of these reports were short term and included only small cohorts. Purpose: To determine the results of surgical hip dislocation in a large cohort of FAI patients at a midterm follow-up. Study Design: Case series; Level of evidence, 4. Methods: A retrospective study including 185 consecutive patients (mean age, 30 years; 40% female) with 233 hips treated was conducted. We determined clinical outcomes in terms of range of motion and analyzed radiographs for several criteria including the alpha angle preoperatively and at 1 year postoperatively. At latest follow-up, on average 61 months postoperatively, patient satisfaction, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hip Outcome Score, SF-12, and University of California, Los Angeles (UCLA) activity scale scores were determined. All revisions and conversions to total hip arthroplasty (THA) were recorded. Results: Both hip flexion and internal rotation improved from preoperatively to postoperatively. Alpha angles decreased from 65.1° ± 14.2° to 42.4° ± 4.9°. At 5 years, 82% of the patients were satisfied or very satisfied with the results of surgery, and 81% would undergo the same surgery again. There were 83% who rated their overall hip function as normal or nearly normal. Mean scores for the WOMAC pain, stiffness, and function subscales were 10.3 ± 15.8, 15.9 ± 17.4, and 9.6 ± 13.0 points; for Hip Outcome Score activities of daily living and sport subscales were 89.0 ± 13.1 and 75.6 ± 23.0 points; and for the SF-12 Physical Component Scale and Mental Component Scale were 47.4 ± 6.3 and 52.3 ± 7.4 points, respectively. The mean UCLA activity level was 7.7 ± 1.9. Conversion to THA was performed in 7 hips (3%). Seven hips (3%) underwent other major revisions, and 11 (4.7%) underwent minor revisions. Female patients had a significantly increased risk for conversion to THA (odds ratio, 13.3; 95% confidence interval [CI], 1.3-92.6) and major revision (odds ratio, 19.2; 95% CI, 2.4-152.9). The mean body mass index was significantly lower in those patients who underwent conversion to THA. The need for microfracture because of residual full-thickness cartilage defects after rim trimming was a significant ( P = .04) predictor of subjective dissatisfaction. Conclusion: This study demonstrates that surgical hip dislocation is a successful procedure for the treatment of FAI. A majority of patients were satisfied with the results of surgery at a midterm follow-up. Older and slim female patients were at an increased risk for a less successful outcome in terms of conversion to THA and revision surgery.