Evaluation of Retracted Distance in Full-thickness Rotator Cuff Tears with Delamination by using an MR Arthrography

Abstract

Delamination is one of the horizontal tears combined with articular side tears and bursal side tears observed in full-thickness rotator cuff tears. However, this pathology is not well known about in detail. MR arthrography was reported by us to be an effective imaging procedure for intra-articular lesions. The aim of this study was to investigate the characteristics of delamination by measurements of their sizes with MR arthrography. We retrospectively evaluated 43 patients in which we observed delamination arthroscopically. Computerized measurements of the sizes of the superficial tears and the difference between superficial tears and deep tears were performed using the method previously reported by Toyoda et al. We statistically analyzed correlations between superficial tear sizes and the differences as well as patients' age and the differernces. Thirty-seven shoulders (86%) in 43 patients were eligible for evaluation by MR arthrography. There was no correlation between patients' ages and the differences. The differences in each full-thickness tear sizes' group were small: 1.32±0.64, medium: 1.20±0.52, large: 0.37±0.88, massive: -1.66 respectively. The smaller difference between superficial tears and deep tears with delamination were observed in the larger sizes of superficial tears. The smaller difference between superficial tears and deep tears with delamination were observed in the larger sizes of superficial tears.