Quantification of Cellularity and Lipoid Degeneration to Assess Localized Degeneration in Rotator Cuff Tendons

INTRODUCTION Degenerative rotator cuff tears are a common problem, affecting greater than 30% of the general population [1]. Rotator cuff tears most commonly occur in the supraspinatus tendon near the insertion site [2]. There is a high failure rate of rotator cuff tear repairs, and this failure typically occurs at the tendon-suture interface [3]. By determining localized differences in rotator cuff tendon degeneration, surgical techniques can be improved. Past studies have evaluated localized tendon degeneration, but these studies only focused on one location in the tendon, such as the medial edge of a chronic tear [2]. Sano et al. discovered a relationship between decreased tendon mechanical properties and increased tendon degeneration at the insertion of the supraspinatus tendon [2]. Therefore, the objective of this study is to evaluate localized tendon degeneration in multiple locations by quantifying cellularity and lipoid degeneration, two characteristics of tendon degeneration.