Q: I just found out that I have a rotator cuff tear and damage to the biceps pulley. I'm having surgery next week for both. Are these two problems part of the same thing, separate issues, related to each other, or what?

A: Let's start with describing the biceps pulley. The full name of the pulley mechanism is biceps reflection pulley. It is a sling of soft tissue fibers made from surrounding shoulder ligaments and tendons of the shoulder rotator cuff. The sling helps keep the biceps tendon inside a groove in the humerus (upper arm bone) along the front of the upper arm and shoulder.

Disruption of the biceps pulley (usually from a rotator cuff tear) allows the biceps tendon to sublux (partially shift out of the groove) or dislocate (pop out fully). The result can be anterior shoulder pain (along the front of the upper arm) and/or shoulder instability.

In a recent study, it was reported that one-third of patients referred to a shoulder specialist with a shoulder problem, indeed, have a biceps pulley lesion. In most cases, the biceps pulley lesion was present when the patient had a rotator cuff tear and SLAP lesion.

SLAP refers to a superior labral anterior-posterior tear. The labrum is a rim of fibrous cartilage around the shoulder socket. This little extra lip helps keep the shoulder in the socket. The SLAP lesion refers to a labral tear at the top of the socket (that's what superior means) that goes from the front (anterior) to the back (posterior) of the socket.

The biceps tendon is intimately linked with the labrum because it attaches along the upper front area of the socket. In some SLAP lesions, the biceps tendon is also pulled away from the bone. In the study we mentioned, almost 80 per cent of the entire group had a biceps pulley tear and a rotator cuff tear at the same time.

Surgeons may not always be aware of the biceps pulley system. The loss of this restraining mechanism may contribute to continued shoulder pain after repair of a torn rotator cuff tendon. A proper inspection of the biceps pulley is advised. Repair of this anatomic feature may improve surgical outcomes.

Future study of this biceps pulley mechanism is needed to find out which comes first: degeneration and disruption of the pulley system or rotator cuff lesions? Since many of the biceps pulley lesions were in older adults, it may be that an injury to the biceps tendon leads to disruption of the pulley mechanism.

The end result may be weakening of the rotator cuff with eventual damage there as well. On the other hand, seniors are also at increased risk of rotator cuff tendon degeneration and disruption, which could create the chain of events that leads to biceps pulley lesions.

Reference: Sepp Braun, MD, et al. Lesions of the Biceps Pulley. In The American Journal of Sports Medicine. April 2011. Vol. 39. No. 4. Pp. 790-795.