Temporal Evolution of MRI Findings After Arthroscopic Rotator Cuff Repair

OBJECTIVE. The purpose of this article is to assess the changes occurring over time in the MRI appearance of repaired rotator cuff tendons and to correlate MRI appearance with clinical outcomes. SUBJECTS AND METHODS. MRI examinations were performed on 40 patients with full-thickness rotator cuff tears preoperatively and at 6 weeks, 3 months, and 12 months after arthroscopic repair. Preoperative scans were assessed for size of tear. Postoperative scans were evaluated for size of footprint, tendon thickness, signal intensity of the repaired tendon, and presence of full-thickness tear. Footprint and tendon thickness were graded from 1 to 4 according to percentage of normal. Tendon signal intensity was graded from 1 to 4 on the basis of the length of abnormal tendon. A composite score of footprint, tendon thickness, and tendon signal intensity was used to compare overall tendon appearance relative to the intact tendon. Rasch analysis was used to transform ordinal scale data into interval scale data. Using interval scale data, MRI findings were correlated to shoulder strength and the Constant-Murley score of clinical outcome. RESULTS. Four recurrent tendon tears occurred during the first postoperative year. Tendons appeared most disorganized compared with native tendon 3 months after surgery. Twenty-four of 36 intact tendons showed a decreased tendon score between 6 weeks and 3 months. There was considerable variability in tendon appearance among patients. There was no correlation between MRI appearance and clinical outcome score. CONCLUSION. MRI appearance of the repaired tendon changes over time but does not correlate with function or predict clinical outcomes at 1 year after surgery.