Acetabular Labral Tear
What is the acetabular labrum?
The acetabular labrum is a tough cartilage which attaches about the rim of the hip joint socket. The labrum deepens the socket and assists in the stability, lubrication and sensation of the hip joint.
What causes acetabular labral tears?
Acetabular labral tears generally occur in two situations. More frequently, labral tears may occur due to a gradual accumulation of damage over time - this is known as a 'degenerate tear' (Figures 1-4). Degenerate labral tears may develop as a part of hip joint osteoarthritis, or may be related to other hip joint disorders such as developmental dysplasia or femoro-acetabular impingement (FAI). Acetabular labral tears can occur as a result of a single traumatic injury to the hip joint - this situation is reasonably uncommon (Figure 5).
What are the symptoms?
Patients with acetabular labral tears commonly experience groin pain, which is often made worse with physical activity such as impact sports, running and positions where the hip is deeply bent, such as squatting or when rising from a low chair. The symptoms may have been present for a long time in a fluctuating manner and may have been misinterpreted as 'recurrent groin sprains'. Some patients experience 'mechanical' symptoms such as painful catching or unpredictable 'weakness' and giving way of the hip.
Are there any other associated injuries?
Patients who have developed a degenerate labral tear may also have associated damage to the adjacent gliding surface (hyaline) cartilage of the hip joint socket. Sometimes small cysts form around the hip joint as a result of the acetabular labral tear. Patients who have an structural cause for their degenerate labral tear (such as dysplasia or femoro-acetabular impingement) have an underlying abnormality in the shape of the hip joint which has pre-disposed the labrum to accumulating damage.
What about labral tears and arthritis ?
Osteoarthritis is a condition that effects the whole joint, not just the labrum. It is typical for degenerative tearing of the labral cartilage to be observed in association with the development of osteoarthritis. Whilst labral tears may contribute to the pain associated with osteoarthritis, the far more significant factor influencing outcome is the degree of wear sustained to the hyaline (gliding) cartilages lining the joint. In circumstances of significant osteoarthritic wear, treating the labral cartilage tear alone is very highly unlikely to make a worthwhile impact upon the symptoms. For this reason, arthroscopy is rarely recommended for the management of osteoarthritis of the hip, even if a labral tear is observed on MRI. If the degree of ostearthritic wear is of lesser grade, arthroscopic treatment of the labral injury may be effective in reducing pain.