Risk factors for and prognosis of folded rotator cuff tears: a comparative study using propensity score matching

Background: The prognosis of rotator cuff repair (RCR) may be affected by the shape and quality of the torn rotator cuff tendon. However, only a few studies have reported on folded rotator cuff tears (FCTs). Therefore, this study aimed to evaluate the prognostic factors for FCT and clinical outcomes of FCT repair. Methods: Through propensity score matching (PSM), 200 (40 patients with FCTs and 160 controls) of 1927 patients who underwent RCR from 2010 to 2016 were included. The variables not used for PSM were compared. The anatomic and functional outcomes were assessed at the final follow-up (32.3 +/- 21.2 months), and the related prognostic factors for FCTs were evaluated. Results: The risk factors for FCT were heel-type spur (odds ratio [OR], 11.6; P <.001) and delamination (OR, 2.3; P =.034). Although the functional scores at the final follow-up for both groups improved postoperatively and were not significantly different, the visual analog scale scores for pain (1.9 +/- 2.1 vs. 1.2 +/- 1.7, P =.034) and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (83.1 +/- 14.3 vs. 88.5 +/- 12.2, P =.018) were significantly worse in the FCT group at 6 months postoperation. The retear rate was significantly higher in the FCT group (25.0 vs. 10.0%, P =.018). An FCT was a significant risk factor for retears (OR, 3.0; P =.015); however, a subgroup analysis revealed that the retear rate according to the management strategy for the folded portion (debridement of the folded portion vs. en masse repair including the folded portion) was not significantly different (26.7 vs. 24.0%, P >.99). Conclusion: The risk factors for FCTs were heel-type spur and delamination. The retear rate was significantly higher for patients with FCTs. An FCT was indicative of poor quality of the remaining tendon; therefore, FCT may be a prognostic factor for worse functional outcomes during the early postoperative period and poor healing potential. Level of evidence: Level III; Retrospective Cohort Comparison; Treatment Study (C) 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.