Prognostic factors affecting clinical outcomes after arthroscopic rotator cuff repair: importance of functional recovery by 3 months after surgery

Background: To examine important factors that affect clinical outcomes following arthroscopic rotator cuff repair (ARCR). Methods: Among 163 patients who underwent ARCR, we included 71 shoulders in 71 patients whose progress was monitored for > 2 years, postoperatively. We divided the patients into groups A (scores >= 83 points, 59 patients) and B (scores <83 points, 12 patients) using the Japanese Orthopedic Association (JOA) score at 24 months. We then conducted univariate and multivariate analyses of pre- and postoperative (2 and 3 months, respectively) factors. Results: The mean JOA score for all patients significantly improved from 63.7 +/- 11.5 points preoperatively to 90.3 +/- 9.6 points at 24 months postoperatively (P<0.05). However, there were no significant between-group differences in the preoperative scores. In addition, there were no significant differences in the postoperative re-tear rate. Univariate analysis revealed that the range of motion (preoperative abduction and postoperative elevation, abduction, internal rotation, and external rotation), muscle strength (external rotation 3 months postoperatively), postoperative pain level [visual analog scale (VAS) maximum score, 10 points], partial repair, Cofield classification, and preoperative width were significant factors (P<0.05 for all factors). Multivariate and receiver operating characteristic curve analyses showed that VAS at 2 months postoperatively and elevation at 3 months postoperatively were significant factors. Conclusions: To obtain a JOA score of 83 points at 24 months postoperatively, following ARCR, a postoperative VAS of <5 points at 2months and postoperative elevation of >= 110 degrees at 3 months should be achieved.