Study suggests changes in rotator cuff surgery rehabilitation needed

NEW YORK – A new study by the Hospital for Special Surgery suggests that rehabilitation for patients undergoing for tendon-bone repairs such as rotator cuff surgery may be partially to blame for the high rates of failed healing after surgery.

The rotator cuff is a set of a four shoulder muscles that allow the upper arm to rotate. When torn, the tendon of the muscle tears away from the bone of the upper arm. Repair surgery requires reattachment of the tendon to the, with success being dependent on how well the interface between the tendon and bone heals. Studies have shown that 20%-40% of patients undergoing rotator cuff surgery have failed healing.

Rehabilitation after rotator cuff surgery usually consists of immobilizing the shoulder in a sling for seven to ten days, physical therapy with passive and assisted motion for six weeks, followed by physical therapy with active motion for six weeks.

A rat model of the injury suggests that immobilizing the limb for four to six weeks after surgery improves healing.

The researchers at the Hospital for Special Surgery used a small metal frame to hold the joint in place and then used a specially designed motorized device to precisely apply loads of strain. One group of rats received a low load 50 times per day (analogous to a leg extension with no weight), another group received a moderate load 50 times per day and a third group had their joint immobilized for the entire study period. The animals were studied at 4, 10, 21, and 28 days.

The study shows that rats that had their joint immobilized had the best healing, with significantly less fibrocartilage or scar tissue than rats in the other two groups, better connective tissue organization, higher load to failure, better bone mineral density, and fewer dead cells in the area that was operated on.

This implies that the best path to recovery for patients undergoing rotator cuff surgery might be to keep individuals in slings for six weeks and then start with passive motion therapy. However, studies are needed in humans to test this hypothesis and make firm clinical recommendations.