A SLAP tear is an injury to the labrum of the shoulder, which is the ring of cartilage that surrounds the socket of the shoulder joint.
The shoulder is a ball-and-socket joint made up of three bones: the upper arm bone (humerus), the shoulder blade (scapula), and the collarbone (clavicle).
The head of the upper arm bone fits into a rounded socket in the shoulder blade. This socket is called the glenoid. Surrounding the outside edge of the glenoid is a rim of strong, fibrous tissue called the labrum. The labrum helps to deepen the socket and stabilize the shoulder joint. It also serves as an attachment point for many of the ligaments of the shoulder, as well as one of the tendons from the biceps in the arm.
The term SLAP stands for Superior Labrum Anterior and Posterior. In a SLAP injury, the top (superior) part of the labrum is injured. This top area is also where the biceps tendon attaches to the labrum. A SLAP tear occurs both in front (anterior) and back (posterior) of this attachment point. The biceps tendon can be involved in the injury as well.
Injuries to the superior labrum can be caused by acute trauma or by repetitive shoulder motion. An acute SLAP injury may result from:
- A motor vehicle accident
- A fall onto an outstretched arm
- Forceful pulling on the arm, such as when trying to catch a heavy object
- Rapid or forceful movement of the arm when it is above the level of the shoulder
- Shoulder dislocation
People who participate in repetitive overhead sports, such as throwing athletes or weightlifters, can experience labrum tears as a result of repeated shoulder motion.
Many SLAP tears, however, are the result of a wearing down of the labrum that occurs slowly over time. In patients over 40 years of age, tearing or fraying of the superior labrum can be seen as a normal process of aging. This differs from an acute injury in a person under the age of 40.
Signs & Symptoms
The common symptoms of a SLAP tear are similar to many other shoulder problems. They include:
- A sensation of locking, popping, catching, or grinding
- Pain with movement of the shoulder or with holding the shoulder in specific positions
- Pain with lifting objects, especially overhead
- Decrease in shoulder strength
- A feeling that the shoulder is going to “pop out of joint”
- Decreased range of motion
- Pitchers may notice a decrease in their throw velocity, or the feeling of having a “dead arm” after pitching
In addition to medical history, a physical examination will be conducted to check the range of motion, strength, and stability of the shoulder.
Specific tests (such as the O’Brien’s test) may be performed by placing the arm in different positions to reproduce the symptoms. The neck and head may also be examined to make sure that the pain is not coming from a “pinched nerve”.
The results of these tests will help to decide if additional testing or imaging of the shoulder is necessary (ie. X-ray, MRI).
In many cases, the initial treatment for a SLAP injury is non-surgical. Treatment options may include:
- Non-steroidal anti-inflammatory medication – Drugs like ibuprofen and naproxen reduce pain and swelling.
- Physical therapy – specific exercises will restore movement and strengthen the shoulder.
Surgery may be recommended if the pain does not improve with non-surgical methods.
Arthroscopy – The surgical technique most commonly used for repairing a SLAP injury is arthroscopy. Because the arthroscope and surgical instruments are thin, very small incisions (cuts) can be used, rather than the larger incisions needed for standard, open surgery.
There are several repair options for different types of SLAP tears. This may require simply removing the torn part of the labrum, or reattaching the torn part using stitches. Some SLAP injuries requires cutting the biceps tendon attachment.
The best repair option will be decided based upon the type of tear, age, activity level, and the presence of any other injuries.
Post-surgery, the arm will be immobilised in a sling for 2 to 4 weeks depending on the severity of the injury. Physiotherapy will start once the initial pain and swelling has settled down.