Supraspinatus Tendon Structural and Mechanical Properties in a Chronic

INTRODUCTION Rotator cuff tears of the shoulder are a common cause of pain and disability and surgical repair of these injuries is plagued with recurrent tear rates ranging from 20-70% [1]. The time from onset of injury to time of surgical repair is one important factor in repair outcome [2]. Animal models have recently been developed to address hypotheses related to rotator cuff tendon to bone injury and repair [3]. However, these studies model an acute injury and repair condition, while the most common clinical presentation is that of chronic or acute on chronic injuries. The healing pathway and potential in these two situations may be fundamentally different. Therefore, the objective of this study is to develop an animal model of chronic rotator cuff tendon tears that would be useful in studying this common clinical problem. In this study, we hypothesize that increased time post-injury will result in increased detrimental changes to supraspinatus tendon organizational and mechanical properties.