Muscle Injury Induced At the Time of Acute and Chronic Rotator Cuff Repair

摘要

Objectives:Rotator cuff tears are a common source of shoulder pain and disability. Even after surgical repair of these tears, many patients continue to have reduced shoulder function and a progression of intramuscular fatty degeneration. Previous work in a sheep model demonstrated that a slow, progressive lengthening of chronically torn cuff muscles followed by surgical repair of the tendon reversed fatty degeneration and improved muscle function. As patients with chronic cuff tears often experience a shortening of the muscle fibers, it is possible that repairing the torn tendon to its original anatomical footprint induces a massive stretch-induced muscle injury that could contribute to poor outcomes after repair. Evans Blue Dye (EBD) is a water soluble, membrane impermeable dye, that is used to identify muscle fibers that have suffered an injury to their plasma membrane. We hypothesized that, compared with acutely torn and repaired rotator cuff muscles, the substantial stretch that is required to repair a chronically torn and shortened rotator cuff would result in significant muscle fiber damage.