Expression of procollagen alpha 1 type III mRNA in rotator cuff tears

The purpose of this study was to investigate the relationship among expression of procollagen alpha 1 type III mRNA, subacromial adhesion, and limited shoulder elevation in rotator cuff tears. Procollagen alpha 1 type III mRNA was analyzed in the torn supraspinatus tendons and synovial tissue of 42 patients with rotator cuff tears. As a control, four normal supraspinatus tendons of patients who had undergone shoulder surgery other than rotator cuff repair served as controls. Cells stained positively for procollagen alpha 1 type III mRNA were more abundant in the adhesive synovium of the subacromial bursa and in the torn supraspinatus tendons than in controls. Patients with complete-thickness tears who had undergone surgery less than 10 months after trauma were found to have more signal-positive cells than those later than 10 months. We conclude that the adhesive synovium of the subacromial bursa contains abundant cells stained positively for procollagen alpha 1 type III mRNA. We suggest that the production of type III collagen by these cells could contribute to the limitation of shoulder motion in patients with rotator cuff tears, and recommend release and excision of the excess adhesive synovium during rotator cuff surgery.