Anterior Inferior Iliac Spine and Hip Abnormalities in High-Level Soccer Players: A 3-Dimensional CT Analysis

Abstract

Soccer is a sport requiring repetitive forceful kicking and hip rotation and has been associated with acute avulsion injuries of the anterior inferior iliac spine in the pediatric population. While the etiology of abnormal AIIS morphology remains unknown, it may relate to abnormal stresses or injury to the AIIS apophysis during skeletal development. The purpose of this study was to evaluate anterior inferior iliac spine and hip abnormalities in high-level soccer athletes with hip injuries requiring hip arthroscopy. A retrospective review of the 3D CT scans and registry data of 38 male and 19 female high-level soccer players was performed to determine the prevalence of anterior inferior iliac spine and hip abnormalities. Only athletes who underwent hip arthroscopy for femoroacetabular impingement were included. Sport foot dominance was also correlated with the involved hip. Bilateral cases were also included. Abnormalities of the anterior inferior iliac spine were classified using a previously published and validated classification system. Femoral and acetabular morphology were also characterized using three-dimensional imaging and radial sequences to define the location and magnitude of maximal deformity. There were a total of 71 hips (46 male and 25 female). 89.1% (41/46) of male hips and 84% (21/25) of female hips in high-level soccer players demonstrated some abnormality of the anterior inferior iliac spine. In males, 52% of hips were classified as type II AIIS morphology while 37% were type III. In females, 68% of hips were classified as type II and 16% were type III. The average maximum alpha angle was 69.3±13.3 and 55.6±12.9 degrees in males and females, respectively. In males, the acetabular coronal and sagittal center edge angles were 31.5±5.8 and 53±8.6 degrees, respectively. The acetabular version in males was 1.3±10.1 degrees at the 1-o'clock position and 15.2±5.5 degrees at 3 o'clock. In females, the coronal and sagittal CEA were 30.7±6.1 and 58.2±8.4 degrees. Acetabular version at the 1- and 3-o'clock positions were -1.2±9.5 and 13.2±8.3 degrees, respectively. 72% (41/57), including bilaterals, had surgery on their dominant extremity. All of the patients with bilateral surgery had their initial procedure on their dominant extremity. The prevalence of an AIIS morphology that extends to or below the acetabular margin of high level soccer players is considerable, particularly in the male athletes. There is also a high prevalence of cam-type femoral abnormality with increased alpha angles. In the majority of the soccer players, the dominant extremity appears to be more or initially symptomatic requiring surgical intervention. Based on these findings, in addition to femoroacetabular impingement, there should be a high index of suspicion for subspine impingement in soccer players. This pathomorphology may reflect the sequelae of the forceful repetitive kicking involved in the soccer and forces on the developing AIIS apophysis.