shoulder labrum

PT Corner with Kristin Williams

Shoulder Labral Tear

By Kristin Williams

Oct 18, 2021

Many of you who practice with me regularly may know that I have a cranky right shoulder. Almost three years ago, I was working on a fellow physical therapist who is around 6’2” and roughly 250 lbs after a long morning of treating patients. His back was bothering him so, of course, I wanted to help him out. I went to manipulate his sacroiliac joint, a maneuver which requires me to thread my arm through his in a particular manner where my right shoulder is flexed and internally rotated. Now I’ve done this technique thousands of times without any issue, but this time when I went to lean away and use my body weight to roll him, I felt and heard a tearing in that shoulder. In fact, he heard it too. He looked at me, I looked at him, and we simultaneously muttered, “uh oh”. I never had any diagnostic tests done and rehabbed it myself, but I suspect I tore my labrum.

 

The labrum of the shoulder is a fibrocartilaginous rubbery rim attached around the margin of the socket of the joint called the glenoid fossa, which is part of the scapula (shoulder blade). The socket is quite shallow and small, covering at most only a third of the ball (the head of the humerus). One function of the labrum is to deepen the socket. It increases the contact area between the ball and socket by 2 mm at the front and back and 4.5 mm at the top and bottom. If you took a cross-section of the labrum, it would look like a triangle, where the wide base attaches to the edge of the socket, leaving the edge of the labrum thin and sharp at the point. This shape allows it to almost act like a washer, sealing the ball and socket together. This is called a “viscoelastic piston effect” and maintains a negative pressure within the joint, which is especially effective against traction or pulling stresses and, to a lesser extent, against shearing stresses. Finally, the labrum provides an insertion point for stabilizing structures, including the joint capsule ligaments and the tendon of the long head of the biceps muscle.

shoulder labrum

 

The labrum is described like the face of a clock, with 12 o’clock being at the top (superior), 3 o’clock at the front (anterior), 6 o’clock at the bottom (inferior), and 9 o’clock at the back (posterior). Most instabilities in the shoulder are associated with injuries to or changes within the glenoid labrum, particularly where the long head of the biceps tendon inserts at the superior (12 o’clock) portion. They are commonly called SLAP tears, as they involve a superior lesion running from anterior to posterior, usually between 10 and 2 o’clock.

 

There are different types of SLAP tears that typically involve different mechanisms of injury. A common mechanism is falling on an outstretched arm or a sudden pull when lifting a heavy object, like I did with my fellow PT. Other mechanisms include repetitive shoulder abduction and external rotation, like many throwers, overhead athletes, or manual laborers perform over and over. A direct blow to the shoulder, as with tackling in football can also be a cause. Finally, SLAP tears can occur in a degenerative manner for the aging population as well.

 

Treatment for SLAP tears includes both non-operative and operative measures, and both have been shown to be successful in certain populations. Previous studies have shown nonoperative management to be successful for 22 to 85% of patients. Operative repair in adults has been reported to be successful between 80 and 97% of the time, by way of alleviation of pain and return of range of motion. However, in overhead athletes, many patients are unable to return to their prior level of sport or performance. Results vary widely in this population, with between 7 and 84% demonstrating return to their prior level of performance. As patients age, typically beyond 40 years old, surgeons often opt to perform a biceps tenodesis (where the tendon of the long head of the biceps is detached from the labrum and anchored to the proximal humerus) instead of a labrum repair, as success rates with repair decline in older populations.

 

I continue to address my shoulder issue with home exercises and activity modifications and so far, so good! As I say all the time in Stretch class, the shoulder joint is our most mobile, but also our most unstable. It requires a high quality of movement for all the parts to work in harmony. Paying attention to how we move on our mats and keeping the ball centered in the socket is important for many reasons, but especially to avoid placing repetitive undue strain on the labrum. So continue using your LYT Yoga® practice to build strength and good brain mapping in the shoulder joint complex! Until then, I’ll see you on the mat!

 

Xoxo,

Kristin

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