SLAP Lesion

A SLAP (superior labrum anterior to posterior) lesion is a tear of the superior glenoid labrum involving the biceps anchor, and a cause of deep shoulder pain in overhead athletes.

It typically affects throwers, cricket fast bowlers, tennis players and swimmers, and can also follow acute trauma such as a fall on an outstretched hand or an anterior dislocation. Most patients are offered structured non-operative treatment first, with surgery for refractory symptoms.

The glenoid labrum is a fibrocartilage rim that deepens the glenoid by around 50% and adds to humeral head stability. The superior labrum blends with the long head of biceps tendon (LHBT) at the supraglenoid tubercle, forming the biceps anchor.

Mechanisms of injury:

• •Peel-back (Burkhart): in abduction and external rotation the LHBT twists posteriorly and loads the posterosuperior labrum; typical in throwers and of posterior-extending type II lesions
• •Traction: a sudden eccentric biceps load, such as catching a heavy falling object
• •Compression: a fall onto an outstretched hand with the arm abducted
• •Dislocation: anterior dislocation in contact sport can cause a combined SLAP and Bankart lesion

The Snyder classification (types I to IV) is the one most commonly used and tested, and type II is the most common, at roughly half of lesions. Type II lesions may extend anteriorly, posteriorly or both (Morgan), with posterior extension common in throwers. Later classifications add further types for complex patterns.