Femoroacetabular impingement (FAI) is a multifactorial hip disease in which pain is a direct result of a collision of femoral head (the ball of the hip joint) with the edge of the acetabula (the socket of the hip joint). The hallmark of the disease is pain provoked by hip flexion. Although impingement occurs during flexion of the hip joint such as with sitting, squatting and lifting the hip. Once the impingement is established the pain may appear on walking, kicking and sporting activities involving body rotation over the planted leg. This occurs because the hip joint labrum becomes damaged and the capsule becomes inflamed. The joint space may not become decreased until the progression of the disease. Labral tears may or may not be present with FAI.