→ an injury to the glenoid labrum.
A superior labral lesion is a tear to a part of the shoulder called the glenoid labrum. This is a circular rim of fibrocartilaginous tissue that sits around the socket of the arm (the glenoid cavity). It helps to seal and stabilise the joint between the socket and the ‘ball’ part of the arm bone (the glenohumeral joint). Doctors categorise labrum tears in different ways: a tear extending towards the front of the shoulder is known as an ‘anterior’ tear. One extending towards the back is known as a ‘posterior’ tear. The term ‘superior’ refers to the upper part of the labrum. Hence, a tear to the top part of the labrum extending to the back and front of the labrum is known as a Superior Labral Anterior-Posterior lesion – or SLAP tear for short.
There are four main types of tear (and several other, less common types). In simple terms, Type 1 is a partial tear of the labrum; Type 2 (the most common kind) is when the superior labrum tears away completely from the glenoid bone; Type 3 is when the labrum tears and hangs into the joint below, causing ‘locking’ or ‘popping’; Type 4 is a tear that extends from the labrum into the upper part of the biceps tendon.
SLAP tears can occur through repetition or through trauma. Repeated overhead activities – such as a tennis serve, for example, or swimming strokes and cricket throws – may weaken the labrum tissue over time until a tear occurs. Traumatic injury is another common cause; it’s usually the result of a collision or dislocation, or after an awkward fall and twist of the arm, or when the arm is pulled suddenly. For all these reasons, sportspeople are at greater risk of suffering a SLAP tear, particularly if the sport involves strenuous overhead movements, although natural ageing can make people more susceptible to tears, too.
SLAP lesions tend to cause pain in the upper part of the shoulder, around the superior portion of the labrum. The pain can be felt as a vague, dull ache, which may increase during exertion – particularly with overhead activities. The discomfort may make it difficult to sleep. Depending on the type of tear, patients may also feel a ‘catching’ or ‘clicking’ sensation in the shoulder when throwing, for example. Sportspeople often say that they feel a loss of strength in the arm as well.
Diagnosis of a SLAP tear begins with a physical examination of your shoulder, during which we will talk through your symptoms and how they came about. If we suspect there are complications to surrounding bones, we may recommend an x-ray. MRI scans, unlike x-rays, can pick out the labrum tissue – so we may recommend one in order to help identify the presence, and extent, of the tear.
In the early stages of a SLAP tear, we may recommend pain relief and anti-inflammatory medication to control discomfort and reduce swelling. In the longer term, you may need to consider surgery to repair the damage – but this will depend on the severity of the tear, and on how much it is affecting your day-to-day life. SLAP repair operations are carried out arthroscopically, ie with keyhole surgery. The precise surgical technique depends, again, on the type of tear, but they vary from debriding (or cleaning up) frayed tissue, to repairing and / or reattaching the labrum.