There is increasing evidence for a multi-stage model of rotator cuff (RC) tendon tears, wherein healing is affected by tear size. The underlying pathophysiology however is not fully understood. Changes in the production and remodeling of the RC extracellular matrix (ECM) are likely to be important determinants of RC tendinopathy as they affect healing and the ability to bear loads. This study aimed to gain greater insight into size related tear pathogenesis by analyzing gene expression profiles from normal, small and massive RC tears. The genetic profiles of 28 human RC tendons were analyzed using microarrays representing the entire genome. 11 massive and 5 small torn RC tendon specimens were obtained from tear edges intraoperatively, and compared to 12 age matched normal controls. Semiquantitative real-time polymerase chain reaction (RT-PCR) and immunohistochemistry were performed for validation.INTRODUCTION
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