Surgical dislocation of the hip versus arthroscopic treatment of femoroacetabular impingement: a prospective matched-pair study with average 2-year follow-up.

PURPOSE: The purpose of this study was to prospectively compare outcomes of patients receiving surgical hip dislocation and those undergoing arthroscopic treatment for femoroacetabular impingement (FAI), using a matched-pair analysis.

METHODS: Between January 2008 and August 2011, patients aged 30 years or younger with a diagnosis of FAI treated with surgical dislocation or arthroscopy were included. Patients were excluded with Tönnis grade 2 or greater, dysplasia, Legg-Calve-Perthes disease, and previous hip surgery. Patients treated with surgical dislocation were pair-matched to patients treated arthroscopically in a 1:2 ratio. Patient-reported outcomes were prospectively obtained in all patients preoperatively and postoperatively at 3 months, at 1 year, at 2 years, and at latest follow-up. Alpha angles were measured preoperatively and postoperatively for both groups. Revision surgery and complications were recorded for each group.

RESULTS: Ten patients were included in the surgical dislocation group, and 20 pair-matched patients were included in the arthroscopic group. We obtained 100% follow-up at a mean of 24.8 months in the open group and 25.5 months in the arthroscopic group. Preoperative scores were similar between the 2 groups; significant improvements were made postoperatively for both groups. When we compared the 2 groups, the change in Hip Outcome Score-Sport-Specific Subscale (42.8 v 23.5, P = .047) and 2-year Non-Arthritic Hip Score (94.2 v 85.7, P = .01) were significantly higher in the arthroscopic group. Both groups showed a significant decrease in the alpha angle postoperatively (P = .775).

CONCLUSIONS: Favorable results were shown with both approaches, with significant improvement in all patient-reported outcome measures and high patient satisfaction ratings. However, arthroscopic treatment of FAI showed greater improvement in the Hip Outcome Score-Sport-Specific Subscale and a higher absolute Non-Arthritic Hip Score at an average 2-year follow-up.

LEVEL OF EVIDENCE: Level II, prospective matched-pair comparative study.