What is Femoroacetabular Impingement? Femoroacetabular impingement or FAI is a condition of too much friction in the hip joint.  Basically, the ball (femoral head) and socket (acetabulum) rub abnormally creating damage to the hip joint.  The damage can occur to the articular cartilage (smooth surface of the ball or socket) or the labral cartilage (soft … Continue reading Femoroacetabular Impingement (FAI)