EFFECTS OF BICEPS REROUTING ON IN VIVO GLENOHUMERAL KINEMATICS IN THE TREATMENT OF LARGE-TO-MASSIVE ROTATOR CUFF TEARS

The arthroscopic repair with biceps rerouting (BR) technique has been determined with promising clinical and biomechanical outcomes for treating large-to-massive rotator cuff tears (LMRCTs). However, the in vivo effects of BR on glenohumeral kinematics during functional shoulder movement have not been fully elucidated. To investigate whether BR provides better restoration of shoulder kinematics as compared with conventional rotator cuff repair (RCR). Cohort study; Level of evidence, 3. Patients who underwent either repair with the BR technique (BR group) or RCR alone (RCR group) for treating LMRCTs between January 2021 and May 2022 were enrolled. They underwent 1-year postoperative kinematic evaluation of bilateral shoulders by performing scapular plane abduction within a dual-fluoroscopic imaging system. The glenohumeral translations in the superior-inferior (S-I) and anterior-posterior (A-P) directions were assessed at each 10° shoulder abduction angle. Moreover, the mean, maximum, minimum, and range of glenohumeral translations were calculated throughout the entire movement. A total of 18 patients were included in the final analysis, comprising 9 undergoing BR and 9 undergoing RCR. In the RCR group, as compared with contralateral shoulders, the operative shoulders showed increased superior humeral head translations during lower abduction angles of 30° to 50° (all P < 0.004), with a greater maximum (P = 0.014) and a larger range (P = 0.002) for S-I translations throughout the entire movement. In the BR group, no significant differences between operative and contralateral shoulders were detected in any kinematic variables for the S-I direction (all P > 0.132); however, the operative shoulders exhibited a larger maximum (P = 0.031), a smaller minimum (P = 0.008), and a larger range (P < 0.001) for the A-P translations throughout the entire motion compared with contralateral shoulders. BR successfully reduced residual superior humeral translation compared to conventional RCR and restored normal S-I glenohumeral kinematic in the treatment of LMRCTs. However, the A-P glenohumeral kinematics were not fully restored after BR and its effect on the long-term clinical outcomes required further investigation. BR can be a promising technique to treat LMRCTs while its potential adverse effects on the A-P glenohumeral kinematics should not be ignored, which still required further clinical evidence to determine the long-term outcomes.