Shoulder Labral injuries: SLAP and Bankart Lesions

Anatomy

The shoulder is a “ball and socket” joint, similar to the hip. But unlike your hip, a deep ball and socket, the shoulder socket is very shallow. This is a reason why the shoulder has the most range of motion of all our joints.  A thick, fibrous rim of cartilage called the “labrum” surrounds the entire outside edge of the socket and deepens the joint, increasing its stability. This labrum is also an attachment point for several ligaments and tendons, including the tendon of the biceps muscle, which attaches to the very uppermost (superior) edge of the labrum.

The labrum shares some similar characteristics with the knee’s meniscus.  The lower labrum is typically tightly attached to the bony glenoid rim, while the superior labrum is more “meniscus like” with a less secure union.  The labrum deepens the shallow glenoid fossa by 5-9 mm.  Fifty percent of the glenoid depth is from the labrum. Like the meniscus of the knee, the labrum has a good blood supply at birth but that diminishes as we age.

Injuries:

The two most common types of labral injuries are tears and Bankart tears (Bankart lesions). SLAP tears occur at the front of the upper arm where the biceps tendon connects to the shoulder. Bankart tears typically occur with shoulder dislocation in younger patients; the head of the humerus either shifts forwards, “anterior instability,” or backwards, “posterior instability.”

SLAP tear

The term “SLAP” stands for Superior Labrum Anterior to Posterior, and is used to describe a tear or detachment of the labrum that begins at the anchor site for the biceps (anterior) and extends backward (posterior) from this point. A “SLAP tear” basically means that the labrum is being peeled away from the underlying bone.

Trauma is responsible for approximately 1/3 of all SLAP tears. Some tears develop more over time from repetitive strain, particularly in older adults whose cartilage becomes more brittle with age. SLAP injuries are common in athletes, particularly throwers. Oddly enough, symptoms from SLAP tears can vary from no symptoms to completely disabling. In fact, about 25% of shoulders probably walk around with one, pain free. When they are painful, complaints tend to include a deep, vague non-specific shoulder pain that is worse with reaching overhead or across the body. Popping, clicking, grinding, and catching are common symptoms associated with SLAP tears.

Bankart Lesion

Shoulder dislocations, or partial dislocations, can tear the lower front portion of the labrum and damage the inferior glenohumeral ligament.  These are Bankart Lesions.  The lower front border of the labrum is stretched too long and is loose, or partially torn away from the bone. The tight seal that the labrum provides here acts as a vacuum seal.  When the labrum is disrupted, this may be lost, destabilizing the shoulder.

On a personal note, I have a suspected bankart lesion.  I had a dislocation event (out and back into socket) when I fell on a basketball a few years back.  One of the things that long lingered me was ‘limp stairs.’ The motion of going down stair’s kind of rapidly with limp shoulders where the traction gave me symptoms like my arm was going to slip out of socket.  More on this later.

Also Read: Protecting Your Vision: Lifestyle Tips for Retinal Health

Labral Tears

Both types of torn laburm are usually accompanied by aching pain and difficulty performing normal shoulder movements. With Bankart tears in particular, patients may feel apprehension that the shoulder may slip out of place or dislocate in certain positions. Patients with SLAP tears may experience pain at the front of the shoulder near the biceps tendon.  Labral lesions are rarely alone, there is usually concurrent tendinopathies or rotator cuff tears.

Testing the Labrum

There are fairly reliable orthopedic tests for labral injuries.  When we perform several of them and they all point towards a labral injury, it probably is. Many times, labral specific testing involves some sort of compression or traction on the joint. Your symptoms and history alone many times can lead us to strongly suspect labral injuries.

Imaging for Labral Injuries

The standard for imaging for labral derangements is an MRI Arthrogram.  This is when a contrast solution is injected into the shoulder capsule to help us visualize the cartilage and ligaments.  The most commonly used contrast agent is gadolinium. Gadolinium is a rare earth metal that is used to highlight specific findings on the MRI. A small amount of gadolinium can be injected into the bloodstream or into a joint to provide contrast enhancement. Other types of contrasting agents are used for other types of imaging tests. For example, people having x-rays or CT scans often have contrast agents, but these are not gadolinium based. For most radiographic studies, the contrast is iodine-based.

For orthopedic conditions, especially looking at the labrum, gadolinium is injected inside of the joint. By injecting contrast within the joint, it becomes easier to visualize damage to cartilage and ligaments.

Imaging Concerns

There has been some recent interest in the safety of gadolinium injected into the body. Most of the research in question has to do with the injection of gadolinium into the bloodstream, so there is very little data looking into the safety of injection of gadolinium into a joint. The concern with injection into the bloodstream is that gadolinium can accumulate and persist in certain tissues of the body. There has also been an association with gadolinium causing worsening of kidney disease in certain people. While this is not a common side-effect, it does raise the possibility of concern.

Between that, the cost, and the fact that an MRI never actually solved anyone’s problems, I am very hesitant to order this without an initial aggressive course of therapy. Getting an Arthrogram is really a step towards surgery, it should only be used when there’s been an good trial of therapy, and the shoulder isn’t responding.  Many labral cases really are surgical cases.  I don’t feel that any imaging study can predict who will end up in the surgeon’s office though, that matter depends on many other factors, and only a trial of care can predict.

Treatment of Labral injuries

Although non-surgical treatment of labral tears is not always successful, most experts, including the American Academy of Orthopedic Surgeons, recommends conservative care prior to considering surgery. Depending on presentation, the initial treatment should focus on reducing pain and inflammation. Practicing modifying and avoiding activities that cause pain, particularly throwing. As your symptoms improve, you will be taught progressively more challenging exercises to help you recover. Unfortunately, SLAP tears recover slowly and some cases do require surgical repair.