Subcoracoid Cyst: A Possible Predictive Marker for Postoperative Retears of Rotator Cuff After Arthroscopic Repair

Abstract

Background: Subcoracoid cysts (ScCs) are often associated with rotator cuff tears, but their relationship with rotator cuff retears remains unclear. Purpose: To investigate the correlation between ScCs and retears in patients having undergone arthroscopic rotator cuff repair. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective analysis was conducted on patients who underwent arthroscopic rotator cuff repair from November 2016 to March 2022. Patients with Patte stage 1 or 2 tears were included. Preoperative magnetic resonance imaging (MRI) assessed subscapularis and supraspinatus tendons, biceps pulley, and ScC volume. Postoperative MRI evaluated the same parameters as preoperative MRI, with the addition of rotator cuff retear assessment. On the basis of preoperative MRI, patients were classified into group A (with cyst) and group B (without cyst). According to postoperative MRI, groups were further divided into A1 (without retear), A2 (with retear), B1 (without retear) and B2 (with retear). Postoperative decrease in ScC volume (ScC delta), Sugaya classification, and Constant score were compared. Results: The study included 109 patients: 69 in group A (A1 = 40, A2 = 29) and 40 in group B (B1 = 35, B2 = 5). The retear rate was significantly higher in group A (34.8%) than in group B (12.5%) (P = .02). In group A, the median (minimum-maximum) ScC delta value was significantly greater in group A1 (2422 mm(3) [257 to 7503 mm(3)]) compared with group A2 (625 mm(3) [-1060 to 1978 mm3]), indicating no recurrence of the ScC (P = .03). Postoperative Constant shoulder scores were higher in the no retear groups (group A1, 79.3 +/- 8.2; group A2, 66.2 +/- 13.4; group B1, 83.2 +/- 8.5; group B2, 61.4 +/- 5.9) (P < .001). Conclusion: For the patients with ScCs detected on preoperative MRI scans, preserved tendon integrity after rotator cuff repair was associated with a reduction in ScC volume. This reduction was evident on postoperative MRI scans when compared with preoperative measurements. Conversely, compromised tendon integrity did not lead to a significant reduction in ScC volume after surgery, potentially suggesting cyst reformation. Therefore, the postoperative identification of an ScC may indirectly indicate rotator cuff retear.