Femoroacetabular impingement.

Femoroacetabular impingement (FAI) of the hip is a well-recognized entity that can cause hip pain and limit range of motion. Although there are 2 types of FAI (cam and pincer), these 2 entities most commonly coexist. Plain radiographs and magnetic resonance imaging are commonly used to assess FAI, and play an integral role in diagnosis in conjunction with patient symptoms and clinical examination. Treatment of FAI is also evolving, with arthroscopic management becoming increasingly more popular. This review provides an overview of the proposed etiology, mechanisms, clinical history, imaging, and treatment of FAI.