Preoperative MRI Rotator Cuff Tendon Stump Classification Correlates with the Surgical Outcomes Following Superior Capsular Reconstruction

Purpose To investigate the correlation between rotator cuff stump classification and postoperative outcomes after superior capsular reconstruction (SCR). Methods A total of 75 patients who underwent SCR between June 2013 and May 2021 were included in this study. Based on stump classification using the signal intensity ratio of the tendon rupture site to the deltoid muscle in the coronal view of preoperative T2-weighted, fat-suppressed MRI scans, the patients were classified into types 1, 2, and 3 with ratios of < 0.8, 0.8–1.3, and > 1.3 (44, 17, and 14 patients, respectively). The American Shoulder and Elbow Surgeons (ASES), Constant, and visual analog scale (VAS) scores for pain and range of motion were evaluated at a minimum of 1 year of follow-up postoperatively. The acromiohumeral distance and RC tear arthropathy according to the Hamada classification were assessed on plain radiography. Postoperative graft integrity was evaluated by MRI at 3 and 12 months postoperatively and annually thereafter. Graft failure was defined as complete discontinuity. Results Clinical and radiological outcomes were significantly improved after SCR. In comparison with type 2 and 3 patients, type 1 patients had significantly higher ASES scores (type 1, 2, and 3 = 84 ± 10, 75 ± 15, and 76 ± 14; all P = 0.014), constant scores (type 1, 2, and 3 = 65 ± 5, 61 ± 9, and 56 ± 13; all P = 0.005), and forward flexion (type 1, 2, and 3 = 155 ± 10, 154 ± 15, and 145 ± 13; all P = 0.013). However, these statistical differences between groups were below the established minimum clinically important difference values for the ASES and Constant scores after rotator cuff repair. The graft failure rate after surgery was lower in the type 1 group than that in the other two groups; however, the difference was not statistically significant (P = 0.749). Conclusion Patients with stump classification type 1 showed significantly better functional scores (ASES and VAS scores) and forward flexion; however, the clinical importance of these differences may be limited. Stump classification may be useful for predicting postoperative clinical outcomes.