The labrum is a ring of soft tissue around the margin of the hip socket that serves several functions. It deepens the socket to provide hip stability and also provides a suction seal to the joint, which helps with joint lubrication. Loss of these functions can damage the joint leading to earlier onset of hip arthritis.
Labral tears can occur both from a specific injury or from repetitive microtrauma as occurs in sports that require pivoting and cutting. Symptoms include pain, clicking, locking, stiffness and giving way. The pain is often located in the groin and may be aggravated by certain positions that pinch the torn fragment between the ball and edge of the socket. Symptoms may be aggravated by pivoting on the hip.
The diagnosis of labral injuries is based on both history, physical exam and imaging studies. Pain may be reproduced by flexion and rotation of the hip. X-rays of the hip may be normal or show evidence of impingement between the ball and socket. An abnormally shaped femoral head (cam lesion), a spur at the upper socket margin (pincer lesion) or a deep hip socket (coxa profunda) may all support the suspicion of a labral tear.
The imaging study of choice to diagnose a labral tear is an MRI, sometimes also with an arthrogram of the hip. The study involves the injection of dye (gadolinium) into the hip joint to outline the anatomical structures. In the presence of a labral tear, dye will leak into the defect in the labrum. Dye injections can also be combined with some local anesthetic to confirm that the pain disappears when the joint is anesthetized. This helps to rule out cause of hip pain outside the joint such as bursitis and sciatica.
The treatment of labral tears generally begins with a nonoperative, conservative approach. This involves a period of activity modification to reduce inflammation in the joint and prevent worsening of the tear. Non-steroidal anti-inflammatory medications (Ibuprofen, Naproxen) can also be used during this time to reduce joint inflammation and pain. Avoidance of provocative activities and positions is also important to reduce symptoms
As hip inflammation may cause stiffness and stiffness may exacerbate impingement, achieving full range of motion is critical. To this end, many patients will benefit from structured physical therapy. In addition to stretching exercises, therapy can improve hip stability by strengthening the core and hip gluteal muscles. In some cases, this may be enough to reduce the symptoms of a labral tear to a manageable level that not require surgical intervention. Kinesiotaping can also help labral tears by putting an external rotation force on the thigh. This is called a SERF strap and stands for Stability through External Rotation of the Femur.
In patients with moderate to severe pain, a cortisone injection into the joint may be beneficial. Cortisone is an anti-inflammatory that can act locally to reduce pain for prolonged periods of time. Repeated cortisone injections are not recommended as they may weaken the cartilage and cause further joint damage. The need for repeated injections also generally indicates that conservative treatment is not succeeding to fix the problem.
Surgical treatment of hip labral tears has improved greatly in the recent past. Hip arthroscopy allows access to the labral tear in a minimally invasive fashion. Depending on the tear size, severity and type, arthroscopy may involve either repair or debridement of the tissue. Labral repair is preferable when possible it restores proper joint function and lubrication and may protect against eventual arthritis. Repair is accomplished by sewing the torn tissue back to its boney insertion using anchors implanted in the socket bone. If the tear is not repairable, removal of the torn and degenerated fragments can reduce impingement and joint damage when these fragments get caught in the joint. Arthroscopy can also allow the surgeon to remove any impinging bone such as that from a cam or pincer lesion.
Recovery from labral repair may take 4-6 months before patients can resume presurgical activities at a normal level. This allows sufficient time for tissue healing and rehabilitation of the joint. Patients who undergo surgical debridement without repair may be able to resume normal activities earlier since there is no need to protect the repair.