Femoroacetabular impingement, or FAI for short, is a hip disorder that has only been proposed and gradually recognized in the last decade, and many undiagnosed pains around the hip and inguinal region are due to the presence of acetabular impingement. It occurs by a mechanism of joint damage caused by abnormal contact stresses between the proximal femur (femoral head and head-neck junction area) and the acetabulum, in most cases due to abnormal bony morphology of the femoral head-neck junction area and acetabular rim. A large body of evidence suggests that femoral acetabular impingement is an important cause of the early onset of osteoarthritis. With the advancement of research and clinical practice, the concept of femoroacetabular impingement has been accepted by more and more physicians, and the level of diagnosis and treatment of femoroacetabular impingement under arthroscopy has been greatly improved. As early as the early twentieth century, some orthopedic surgeons noted the presence of impingement between the femoral head and the acetabulum in patients with certain childhood orthopedic conditions, such as slipped femoral head epiphysis, but only described it as one of the sequelae of such conditions. in 1999, Drs. Myers and Ganz et al. reported that in some patients after periacetabular osteotomy, impingement of the femoral head or cephalocervical junction area with the the anterior border of the acetabulum, which was defined as femoroacetabular impingement (FAI). Later, it was reported that in some cases of posterior rotational deformity healing of femoral neck fractures, impingement of the anterior border of the acetabulum also occurred during hip flexion. Later, it was found that some so-called “normal” hips also had FAI due to abnormal bony morphology of the femoral neck junction or acetabular rim, which produced abnormal stress contact during hip motion. The bony augmentation of the femoral head-neck junction area causes the femoral head to become “out of round”, resulting in cam-like impingement, while excessive acetabular coverage of the femoral head results in pincer-like impingement, often simultaneously. Many patients with unexplained hip and groin area pain were previously often diagnosed with soft tissue injury or inflammation (synovitis, myofasciitis, bursitis, etc.), many of which were due to femoroacetabular impingement. The diagnosed cases have been treated with good clinical results. A considerable relationship between acetabular impingement and osteoarthritis of the hip has been found by performing incisional surgery in patients with femoral acetabular impingement. In 2003, Ganz et al. suggested that femoroacetabular impingement is an important cause of early osteoarthritis in most non-dysplastic hips.