Femoroacetebular impingement associated with abnormal contact, due to a corrupt relation between the proximal femur and acetabulum. Historically first Murray and Stulberg et al. observed some important aspects on etiology of hip osteoarthritis. After them, Ganz et al. popularized the theory that hip osteoarthritis in which previously known as idiopathic etiology (primary osteoarthritis), in fact should be named as secondary osteoarthritis which is trigerred by FAI.

Epidemiological studies with large cohort studies seek the incidence of asymptomatic individuals, the characteristics of symptomatic patients with OA, and the relationship between the FAS and different kinds of sports activities.

Caucasians are more prone to this disease than black and East Asian population. Pincer FAI is typically found in middle-aged females, while the Cam FAI is seen more often in males. Sibling and parental studies revealed increased risk related to inheritence. Also, genetic studies revealed that particular locus of some genes had direct effect on the development of FAI. The intensity and type of sportive activities have direct influence on the development FAI. It is suggested that some kinds of sports like ice hockey or football, even aeorobics and yoga have correlations with FAI.

The etiological studies demonstrated the multifactorial etiology regarding tho FAI. The causative factors can be listed as genetic or developmental factors, athletic activity, recurrent strain, pediatric hip diseases (SCPE, Legg -Calvé Perthes, DDH), and previous surgical interventions on hip. All these factors cause abnormal hip morphology, and by the time acetabular and femoral head cartilage injury occurs; later, all those events lead to osteoarthritis of the hip at young age.