Effect of neuromuscular control on the shoulder function of patients with healed rotator cuff and those with retear after arthroscopic rotator cuff repair

Abstract Purpose To compare functional outcomes such as muscle strength, neuromuscular control and patient‐reported outcomes (PROs) between patients with healed rotator cuffs and those with retears after arthroscopic rotator cuff repair (RCR). Methods One hundred and nine patients who underwent arthroscopic RCR were included (85 in the healed group, 24 in the retear group). Shoulder muscle strength and neuromuscular control index (acceleration time [AT]) were evaluated using an isokinetic device. PROs were assessed using the pain visual analogue scale (VAS), Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES) and University of California at Los Angeles (UCLA) scores. Continuous variables were compared using independent t tests. Multiple linear regression analysis was used to identify the influence of the predictor variables on the dependent variable. Results The muscle strength and ATs for external rotators (ERs), internal rotators (IRs) and forward flexors as well as PROs including VAS, SST and ASES scores, were not significantly different between the two groups pre‐ and postoperatively (n.s.). Multiple linear regression analysis revealed that postoperative ATs for the IRs ( p = 0.006) and ERs ( p = 0.028) in the operated shoulders were closely associated with the postoperative UCLA score. Conclusions Compared with the healed group after arthroscopic RCR, the retear group had no clinically relevant differences in muscle strength, ATs and PROs, including VAS, SST, ASES and UCLA scores. However, postoperative ATs for IRs and ERs in the operated shoulders were a significant predictor of postoperative UCLA scores. Therefore, clinicians and therapists need to be aware of the importance of neuromuscular control in patients who have undergone arthroscopic RCR and prioritize therapeutic exercises to restore neuromuscular control. Level of Evidence Level III.