Anterior Inferior Iliac Spine Deformity as an Extra-Articular Source for Hip Impingement: A Series of 10 Patients Treated With Arthroscopic Decompression

Purpose: To describe an arthroscopic technique for decompression of a prominent anterior inferior iliac spine (AIIS) leading to extra-articular hip impingement and to provide short-term outcome after this procedure. Methods: We retrospectively reviewed office charts, imaging studies, operative reports, arthroscopic images, preoperative and postoperative hip flexion range of motion, and preoperative and postoperative modified Harris Hip Scores in a consecutive series of 10 male patients who had arthroscopic decompression of symptomatic AIIS deformities leading to extra-articular hip impingement. The procedure was performed through standard anterolateral and mid-anterior hip arthroscopy portals that were also used to explore the joint and address concomitant intra-articular pathologies. Results: The mean age was 24.9 years, with 8 of 10 patients aged younger than 30 years. In 9 patients, an anterior cam lesion was identified and decompressed before the AIIS decompression. The mean follow-up time was 14.7 months (range, 6 to 26 months). Hip flexion range of motion improved from 99 degrees +/- 7 degrees before surgery to 117 degrees +/- 8 degrees after surgery (P < .001). The modified Harris Hip Score improved from 64 +/- 18 before surgery to 98 +/- 2 at latest follow-up after surgery (P < .001). Conclusions: Arthroscopic decompression of a symptomatic AIIS deformity is a reproducible procedure that can provide excellent outcomes at short-term follow-up. As opposed to using an open approach for decompressing a prominent AIIS, an arthroscopic approach may be of particular value in patients with mixed intra-and extra-articular sources of hip dysfunction, because it enables the surgeon to address all pathologies with a single arthroscopic procedure. Level of Evidence: Level IV, therapeutic case series.