Abstract
Iatrogenic femoroacetabular impingement following periacetabular osteotomy (PAO) is a well-documented cause of postoperative complications. The anterior inferior iliac spine (AIIS) is an increasingly recognized source of impingement, and previous studies have documented high rates of abnormal AIIS subtypes in dysplastic hips undergoing PAO. This study evaluates the effects of PAO with concomitant AIIS osteoplasty on a range of motion and function. We performed a retrospective study of 63 hips that underwent PAO with concomitant open AIIS osteoplasty. AIIS was classified using 3D-reconstruction Computed tomography (CT) and femoral version was measured on axial-CT. Pre- and post.-operative lateral center-edge angle, Tönnis-angle, and anterior center-edge angle were calculated using X-ray imaging. Hip internal rotation (IR) at 90° flexion was recorded preoperatively, intraoperatively following PAO (pre- and postosteoplasty), and 6 months postoperatively. Pre- and postoperative Merle-d'Aubigné (MDA) scores were compared using pairwise t-test. IR motion changes were compared using repeated measures analysis of variance. Regression analyses evaluated the impact of femoral version on IR before and after osteoplasty. MDA significantly improved postoperatively. Intraoperative IR prior to AIIS osteoplasty was significantly reduced compared to other timepoints, but addition of the osteoplasty improved IR intraoperatively and 6 months postoperatively. No differences were noted in IR between pre- and postoperative examination. The impact of IR restoration with AIIS osteoplasty correlated significantly with femoral version, with greater motion improvement noted in patients with lower version. When planning PAO, careful appreciation of motion parameters is critical. Regardless of AIIS morphology, consideration of an intraoperative AIIS osteoplasty should occur when IR is decreased following acetabular reorientation.