<unk>  is characterized by abnormal contact between the proximal femur and rim of the acetabulum (hip socket). In most cases, patients present with a deformity in the femoral head, or acetabulum, a poorly positioned femoral-acetabular junction, or any or all of the foregoing. The cause of<unk>  is currently unknown, but both congenital and acquired etiologies have been put forth. Studies have shown an increased incidence in siblings, suggesting a genetic component. At least one study has also shown a predilection in the white population. It has also been reported to be more common in males. However, there is no concrete evidence to suggest a genetic trait and instead, the most favored theory currently supports that<unk>  (the cam type in particular) is due to repetitive movements involving the hip (e.g. squatting) in young athletes. Aggravating activities that are commonly reported include repetitive or prolonged squatting, twisting movements of the hip, like pivoting during athletics, getting in and out of cars, and even sitting for prolonged periods. A combination of these factors may also predispose to a form of<unk> ; predominantly, a marginal developmental hip abnormality together with environmental factors such as recurrent motion of the legs within a supraphysiologic range. Three types of<unk>  are recognized (see title image). The first involves an excess of bone along the upper surface of the femoral head, known as a cam deformity (abbreviation for camshaft, which the shape of the femoral head and neck resembles). The second is due to an excess of growth of the upper lip of the acetabular cup and is known as a 'pincer' deformity. The third is a combination of the two, generally referred to as 'mixed.' The most common type seen, approximately 70% of the time, is the mixed type. A complicating issue is that some of the radiographic findings of<unk>  have also been described in asymptomatic subjects. Current literature suggests that the cam type of<unk>  is associated with the development of hip osteoarthritis. Thus far, no correlation has been seen between the pincer type and development of hip osteoarthritis.
Femoroacetabular impingement
Patellar subluxation syndrome
Retrocalcaneal bursitis
Greater trochanteric pain syndrome
Patellar dislocation
Patellofemoral pain syndrome
Facet joint arthrosis
Knee dislocation