A high acromion-greater tuberosity impingement index increases the risk of retear after arthroscopic rotator cuff repair

Abstract

Background No evaluation has been done on the relationship of the acromion–greater tuberosity impingement index (ATI) with retear after arthroscopic rotator cuff repair (ARCR). Our purpose was to evaluate whether a higher ATI is associated with retear after ARCR. Methods 132 patients received ARCR and underwent MRI scan at a one year follow-up to assess tendon healing, and the findings were graded no retear (NR), partial-thickness retear (PR) or full-thickness retear (FR). The ATI, the critical shoulder angle (CSA), acromion index (AI) and lateral acromial angle (LAA) were measured with postoperative radiographs. Functional scores were obtained preoperatively and at a one year follow-up. Results Postoperative Constant scores and ASES scores were significantly different between groups with inferior outcomes in the FR group ( p < 0.05 for all). The UCLA score was significantly better in the NR group compared with the PR and FR groups ( p < 0.05), and in the PR group compared with the FR group ( p < 0.05). For ATI and CSA, the values of the PR and FR groups were larger than the NR group ( p < 0.05 for all), but there were no significant differences between the PR and FR groups ( p > 0.05 for all). No significant differences were observed with regard to the AI and LAA ( p > 0.05, respectively). The repair integrity was positively related to the ATI (0.304, p < 0.05) and CSA (0.252, p < 0.05), but not related to the AI or LAA ( p > 0.05 for both). ATI was not related to any functional scores ( p > 0.05 for all). Conclusion This study revealed that the ATI was positively related to rotator cuff retear. Patients with retears had significantly greater ATIs after ARCR. Level of Evidence: III, case–control study.