Femoroacetabular refers to the place in the hip where the round head of the femur (thigh bone) comes in contact with the acetabulum or hip socket. Two types of impingement are known to cause pinching of the soft tissues in this area.
The cam-type impingement occurs when the round head of the femur isn’t as round as it should be. It’s more of a pistol grip shape. It’s even referred to as a pistol grip deformity. The femoral head isn’t round enough on one side (and it’s too round on the other side) to move properly inside the socket.
The result is a shearing force on the labrum and the articular cartilage, which is located next to the labrum. The labrum is a dense ring of fibrocartilage firmly attached around the acetabulum (socket). It provides depth and stability to the hip socket. The articular cartilage is the protective covering over the hip joint surface.
The rim of the cartilage hangs too far over the head. When the femur flexes (bends) and internally rotates, the cartilage gets pinched. Over time, this pinching or impingement of the labrum can cause fraying and tearing of the edges and/or osteoarthritic changes at the impingement site.
The second type of impingement is called pincer-type (more common in women). In this type, the socket covers too much of the femoral head. As the hip moves, the labrum comes in contact with the femoral neck just below the femoral head.
No matter which type of impingement is present, every time the athlete bends the hip up fully combined with internal rotation of the hip, the femur jams into the pelvis. Besides pain, the athlete experiences decreased hip motion, and difficulty with activities like sitting, climbing stairs, squatting, changing clothes, driving, and sports participation.
Once a diagnosis has been made, a course of action is determined. This may be the wait-and-see approach suggested to you. An alternative conservative (nonoperative) approach may be with antiinflammatories and physical therapy. In some cases, surgery is recommended right away. Early diagnosis and surgical correction may be able to restore normal hip motion. Delaying surgery is possible for other patients but the long-term effect(s) of putting surgery off have not been determined.
A physical therapist will carry out an examination of joint motion; hip, trunk, and knee muscle strength; posture; alignment; and gait/movement analysis (looking at walking/movement patterns). A plan of care is designed for each patient based on his or her individual factors and characteristics.
Nonoperative care starts with activity modification (e.g., avoiding pivoting on the involved leg when there is a labral tear, avoiding prolonged periods of inactivity or activity). This part of the program must be followed for at least six months (often longer).
Improving biomechanical function of the hip involves strengthening appropriate muscles, restoring normal neuromuscular control, and addressing any postural issues. Tight muscles around the hip can contribute to pinching between the femoral head and acetabulum in certain positions. A program of flexibility and stretching exercises won’t change the bony abnormalities present but can help lengthen the muscles and reduce contact and subsequent impingement.
Surgery is advised when there is persistent pain despite a good effort at conservative care and when there are obvious structural abnormalities of the hip. Anyone needing surgery will also benefit from physical therapy first to address muscle imbalances resulting in abnormal movement patterns that lead to femoral acetabular impingement.