Effect of Preoperative Fatty Degeneration of the Rotator Cuff Muscles on the Clinical Outcome of Patients With Intact Tendons After Arthroscopic Rotator Cuff Repair of Large/Massive Cuff Tears

Background: Fatty degeneration of the rotator cuff muscles is associated not only with postoperative retear but also with postoperative muscle weakness; therefore, fatty changes in the muscles may affect the clinical outcome even in patients with these tears who have intact tendons after arthroscopic rotator cuff repair (ARCR). Purpose: To evaluate the effect of fatty infiltration on the clinical outcome in patients with intact tendons after arthroscopic repair of large/massive cuff tears. Study Design: Case-control study; Level of evidence, 3. Methods: One hundred fifty-five consecutive patients with large/massive rotator cuff tears underwent ARCR. Of these, 55 patients (mean ± SD age, 64.4 ± 9.1 years) in whom intact tendons after surgery were confirmed with magnetic resonance imaging at final follow-up (mean ± SD, 2.5 ± 1.4 years) were included in this study. Depending on their University of California Los Angeles (UCLA) score at the final follow-up, they were assigned to either the unsatisfactory group (score ≤27; n = 12) or the satisfactory group (score >27; n = 43). Various clinical parameters affecting the clinical outcome were examined through univariate and multivariate analyses. Results: The UCLA score of all patients significantly improved from 18.1 ± 4.4 points preoperatively to 29.8 ± 4.5 points postoperatively ( P < .0001). The mean preoperative UCLA scores were not significantly different between the satisfactory and unsatisfactory groups ( P = .39). Multivariate analysis showed that the preoperative Goutallier stages of the infraspinatus (odds ratio [OR], 8.87; 95% confidence interval [CI], 1.51-52.0; P = .016) and/or subscapularis (OR, 7.53; 95% CI, 1.58-35.9; P = .011) were significantly associated with outcome. Receiver operating characteristic curve analysis revealed a cutoff value of Goutallier stage 1 in both muscles, with area under the curve values of 0.79 (sensitivity 91% and specificity 51%) and 0.84 (sensitivity 100% and specificity 54%) in the infraspinatus and subscapularis, respectively. Conclusion: Preoperative fatty degeneration of the infraspinatus and/or subscapularis with Goutallier stage 2 or higher was significantly associated with worse outcome in patients with large/massive tears who had intact tendons after ARCR.