Arthroscopic Versus Open Cam Resection in the Treatment of Femoroacetabular Impingement

Purpose: The purpose of this study was to evaluate if osseous correction of the femoral neck achieved arthroscopically is comparable to that achieved by surgical dislocation. Methods: We retrospectively analyzed all patients who were treated with hip arthroscopy or surgical dislocation for cam or mixed type femoroacetabular impingement (FAI) in our institution between 2006 and 2009. Inclusion criteria were complete clinical and radiologic documentation with standardized radiographs. Group 1 consisted of 66 patients (49 female patients, mean age 33.8 years) treated with hip arthroscopy. Group 2 consisted of 135 patients (91 male patients, mean age 31.2 years) treated with surgical hip dislocation. We compared the preoperative and postoperative alpha and gamma angles, as well as the triangular index. Mean follow-up was 16.7 months (range, 2 to 79 months). Results: In group 1, the mean alpha angle improved from 60.7 degrees preoperatively to 47.8 degrees postoperatively (P < .001) and the mean gamma angle improved from 47.3 degrees to 44.5 degrees (P < .001). Over time, the preoperative mean alpha angle increased from 56.3 degrees in 2006 to 67.5 degrees in 2009, whereas the postoperative mean alpha angle decreased from 51.2 degrees in 2006 to 47.5 degrees in 2009. In group 2, the mean alpha angle improved from 75.3 degrees preoperatively to 44.8 degrees postoperatively (P < .001), and the mean gamma angle improved from 65.1 degrees to 52.2 degrees (P < .001). Arthroscopic revision of intra-articular adhesions was performed in 4 patients (6.1%) in group 1 and 16 patients (12%) in group 2. Three patients (2.2%) in group 2 underwent revision for nonunion of the greater trochanter. Conclusions: Osseous correction of cam-type FAI with hip arthroscopy is comparable to the correction achieved by surgical hip dislocation. There is a significant learning curve for hip arthroscopy, with postoperative osseous correction showing improved results with increasing surgical experience. Level of Evidence: Level III, retrospective comparative study.