I had a rotator cuff repair operation last week. They put me in a sling but didn't say how long I will have to wear it. If the tendon is repaired, why can't I move my arm?

After a rotator cuff repair, the arm is immobilized to allow the tear to heal. It takes time for the tendon to really "graft" itself back to the bone. Right now it's being held in place by a button or sutures. Too much motion or the wrong kind of movement can disrupt the repair.

Several studies have shown that the body forms a layer of tissue between the bone and the tendon. This interface is made up of fibers and blood vessels. The bone will gradually fill into this interface. This is a very delicate time in the healing process. The fibrovascular tissue can be ripped away by unexpected or extreme motion.

The length of your enforced "quiet time" depends on several things. First the surgeon assesses how severe was the tear. Then the type of surgery done can make a difference. Most surgeons give their patients an exercise program to start early on.

Don't hesitate to call your doctor or the doctor's nurse and ask some questions about your situation. They usually give the patient some written materials to follow in those early days after surgery.