Acetabular Impingement Management Including Focal and Global Retroversion and the Subspine

Symptomatic acetabular impingement represents a distinct subgroup of patients with femoroacetabular impingement syndrome (FAIS). Acetabular-based impingement, or pincer-type FAIS, is characterized by anterior acetabular over-coverage. Pincer subtypes include focal anterior over-coverage, global anterior over-coverage, relative anterior over-coverage (acetabular retroversion), and anterior inferior iliac spine (AIIS) or subspine impingement. These morphological variants can cause abnormal contact between the acetabulum and the femoral head-neck junction during functional hip motion, leading to a variety of labral and chondral injuries. Diagnosis of pincer-type FAIS requires a thorough history and physical exam as well dedicated imaging, and these aspects should all corroborate the symptoms and diagnosis. When symptoms are refractory to conservative management, surgery should be considered with the approach tailored to the individual patient's specific morphology and pathology. Both open and arthroscopic techniques have been shown to be safe and effective in patients with pincer-type FAIS when patients are appropriately indicated and with careful preoperative planning and surgical execution.