Femoroacetabular Impingement and Labral Tears of the Hip
The hip, like the shoulder, is a ball and socket joint that is made up of the head of the femur (ball) and the acetabulum (socket). The acetabulum is lined with a ring shaped cartilage called the labrum. The labrum acts as a cushion between the bones as well as creating a vacuum- like seal to keep the joint stable. In most individuals, the head of the femur and the acetabulum fit together perfectly. However, certain people may not be so lucky. Their bones may be abnormally shaped or angulated, which may predispose them to femoroacetabular impingement (FAI). This condition occurs when the head of the femur and the rim of the acetabulum have abnormal contact with each other. Predisposed individuals who participate in sports with excessive motion about the hip, such as soccer, hockey or dance, are also more commonly affected by this problem. Pincer Impingement occurs at the rim of the acetabulum. This happens when there is an outgrowth of bone from the normal anatomic rim. This extra bone can “pinch” the labrum, causing a tear. A Cam Impingement occurs on the femoral head. The femoral head develops a “bump” and loses its natural sphericity. The bump can prevent smooth motions and also impinge on the acetabular labrum.
People with FAI will usually complain of groin pain, but may also experience in the front and lateral aspects of their hip. Pain will usually increase with squatting and twisting motions, or may present as a constant ache. X-rays are used first as an assessment tool. The doctor can evaluate for not only for abnormally shaped bone surfaces, but also for arthritis, dysplasia (under-coverage of the femoral head) or acetabular retroversion. The doctor can also make certain measurements of joint space and joint angles. If he or she suspects a labral tear, they will order an MRI. Injecting a dye such as gadolinium into the joint may display a labral tear more clearly because the dye will seep into the torn part of the labrum. To further diagnose a labral tear, an injection of a numbing medication into the joint may also be performed.
If a person is diagnosed with a labral tear, they may first try conservative management such as activity medication, anti-inflammatory medications or physical therapy. If those options are unsuccessful, a hip arthroscopy may be indicated. During this type of surgical procedure, the doctor uses a camera (arthroscope) to look inside the hip joint. He first will address the bony abnormalities on the femur side (femoral chondroplasty), acetabular side (acetabuloplasty), or both. He does this by shaving down to the bone and smoothing it so it is an optimal anatomical shape. He then will concentrate on the labral tear. The size of the tear will depend on how many stitches he will use to repair it. Following surgery, the patient will be in a post-operative brace that will restrict their range of motion to protect the repair. Their weight bearing status may also be limited, dictated by the doctor’s protocol. Patients will usually begin physical therapy within the first week.