Q: I've been doing some research on the internet about rotator cuff tears. Both my husband and my sister were diagnosed with this as the cause of their shoulder pain when they didn't do anything to injure themselves. We are all in our 40s and healthy (but not athletic) so I'm just wondering what causes this to happen?

A: Rotator cuff tears are actually very common -- perhaps one of the most common injuries to the shoulder. From what we know about this problem, there can be multiple factors that contribute to the lesion. As your family has just discovered, not all rotator cuff tears are the result of a traumatic or sports injury.

Sometimes simple anatomy answers the "why me" question. There can be just enough curve in the bone, a dip in the alignment of the tendon, a hooked or sloped acromion (the bone that comes across the top of the shoulder) to create an impingement or pinching of the rotator cuff. After many months and sometimes even years, that impingement can result in a tear of the tissues.

Microtrauma from repetitive overuse is another possible variable contributing to a tendon tear. Degenerative changes associated with the aging process can (and do!) result in rotator cuff tears. And anyone who smokes (or uses tobacco) or who has diabetes is at increased risk for rotator cuff tears (or any soft tissue injuries).

Each individual has his or her own unique risk factors. The only way to know for sure is to consult with the surgeon who is evaluating the case. Questions about past history, past and current activity level, age, and general health can sometimes help. Imaging studies from X-rays, CT scans, and MRIs add additional information to answer the question of why this injury developed.

Reference: Alexander M. DeHaan, MD, et al. Does Double-Row Rotator Cuff Repair Improve Functional Outcome of Patients Compared with Single-Row Technique? A Systematic Review. In The American Journal of Sports Medicine. May 2012. Vol. 40. No. 5. Pp. 1176-1185.