The bony glenoid socket is deepened by a tough, fibrous structure that surrounds the rim of this socket, called the labrum. The labrum helps to keep the humeral head in place during shoulder rotation. It also serves as an attachment for the long head of the biceps and the glenohumeral ligaments which help to stabilise the shoulder. Injury of the labrum may cause detachment of this labrum from the bony socket, tear of these ligaments or tear of the long head of biceps. After a labrum tear, the humeral head may partially or fully displace out of the socket. Recurrent subluxation of dislocation can occur if insufficient healing of the labrum takes place. This is called shoulder instability. The labrum can also develop loose flaps that can slip in between the head and the socket during movement, causing clicking of the shoulder or it can develop fraying as part of wear and tear during abnormal movement of the shoulder.
Trauma in the form of shoulder dislocations is the most common cause of labrum tears. Repetitive movements in extremes of motions during work or sport activities, like throwing, weight lifting and racket sports can also cause the labrum to tear.
Labrum tears causes pain, clicking, locking or limited range of certain movements. Some labrum tears, however, can be pain free.
The position of the labrum tears as well as the shape and extend of the tear, influence classification. Injury to the superior labrum is called a SLAP lesion (superior labrum anterior to posterior) and involves the attachment of the long head of the biceps muscle tendon. Tears of the antero inferior part of the labrum is called a Bankart lesion. Less common is posterior labrum tears.
The type of damage of the labrum that has taken place will influence treatment. If there is limited labrum injury it might respond to rest and inflammatory medication and a gradual resumption of physical activities within pain limits combined with a rehabilitation programme.
Tears that cause chronic instability usually involve an important part of the labrum. It displaces or has healed in an abnormal position and needs to be repaired back on the glenoid rim with bone anchors and suturing material by arthroscopic techniques.