How is it possible that I have a rotator cuff tear and don't remember injuring it?

Q: The orthopedic surgeon who is treating me showed me the MRI results and I definitely have a tear in the rotator cuff. But I don't remember ever injuring this arm so how is that possible?

A: The shoulder joint is a very complex anatomic structure. In the absence of injury, chronic overuse can be one potential cause of a rotator cuff tear. Sometimes the natural angle of the shoulder or perhaps a too-shallow shoulder socket predisposes a person to microtears or other nontraumatic damage. There could be some ligamentous laxity (looseness) that has been present since birth that you just didn't know about.

There may be a problem called scapular dyskinesia leading up to rotator cuff degeneration. In recent years, the important role of the scapula (shoulder blade) in shoulder motion has been recognized.

The scapula and shoulder must move together in harmony and with just the right rhythm and flow. Without this dynamic dance, scapular dyskinesia can develop resulting in shoulder problems and contributing to rotator cuff problems and even shoulder instability.

Determining the cause of the shoulder problem is important so that the right treatment can be applied. Imaging studies such as X-rays, CT scans and MRIs often provide helpful clues. A clearer view of the anatomy can guide the surgeon when making recommendations for conservative (nonoperative) versus surgical treatment.

Rotator cuff strengthening often increases the ability of the humeral head to stay compressed inside the socket. A strong rotator cuff also helps the shoulder resist translational (shear) forces. Restoring normal proprioception (joint sense of its own position) has been shown to improve motor control, thus increasing dynamic stabilization.

The rehab program must address strength, endurance, proprioception, motor control, and coordination of the entire shoulder complex (including the scapula). Such a program is directed and supervised by a physiotherapist. Patients must be advised to plan on at least a six month trial of concentrated efforts in rehab with a lifelong maintenance plan urged.

Some patients with shoulder instability may also do well with a rehab program while others will eventually require surgery. Sometimes recovery of stabilizing motor activity isn't possible without shifting the capsule or repairing the rotator cuff. Other reconstructive techniques may be needed to fix the anatomic cause of shoulder instability. That's where your surgeon will be able to advise you.

Reference: Trevor R. Gaskill, MD, et al. Management of Multidirectional Instability of the Shoulder. In Journal of the American Academy of Orthopaedic Surgeons. December 2011. Vol. 19. No. 12. Pp. 758-767.