Background The supraspinatus plays a critical role in stabilizing the glenohumeral joint and facilitating arm elevation. The biomechanical disruption caused by supraspinatus tears changes the normal force couple balance between the deltoid and rotator cuff muscles, often resulting in superior migration of the humeral head and altered scapulohumeral rhythm (SHR). This study aims to prospectively compare the shoulder kinematics of patients preoperatively and after arthroscopic rotator cuff repair using magnetic inertial measurement units with a motion analysis system. Methods A prospective study was conducted with data collection on 21 patients who underwent shoulder arthroscopy for rotator cuff tear repair. Preoperatively and at a minimum 12-month follow-up, each patient was evaluated using the range of motion (ROM) assessment and the Constant–Murley Score (CMS). Patients were examined using the ShowMotion 3D kinematic tracking system (NCS Lab, Modena, Italy), which uses wireless wearable noninvasive magnetic and inertial measurement units sensors to assess the three-dimensional kinematics of the shoulder. For each plane of elevation (ie, flexion and abduction), the SHR was described by 3 scapulothoracic rotations (ie, protraction–retraction, mediolateral rotation, and posterior–anterior tilting) as a function of humeral anteflexion or humeral abduction. Results Active flexion and external rotation ROM showed statistically significant improvement ( P = .039 and P = .006, respectively). CMS pain, strength, and total showed statistically significant improvement ( P = .039 and P = .006, respectively). All the patients showed a nonstatistically significant difference of the SHR along the entire ROM between pre- and postoperative evaluation. The P value in flexion and abduction was >.05; the only statistically significant value was on tilt at 60° in flexion ( P = .044). Conclusion A persistent scapular dyskinesis was observed after arthroscopic rotator cuff repair. Despite a statistically significant improvement reported for active flexion, active external rotation, and for the total CMS, scapular dyskinesis is not resolved with surgery and may contribute to worse long-term outcomes. Further biomechanical and clinical research studies are needed to define specific rehabilitation programs, to maximize outcomes, and to prevent possible cause of reinjury of the rotator cuff repaired.
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Background The supraspinatus plays a critical role in stabilizing the glenohumeral joint and facilitating arm elevation. The biomechanical disruption caused by supraspinatus tears changes the normal force couple balance between the deltoid and rotator cuff muscles, often resulting in superior migration of the humeral head and altered scapulohumeral rhythm (SHR). This study aims to prospectively compare the shoulder kinematics of patients preoperatively and after arthroscopic rotator cuff repair using magnetic inertial measurement units with a motion analysis system. Methods A prospective study was conducted with data collection on 21 patients who underwent shoulder arthroscopy for rotator cuff tear repair. Preoperatively and at a minimum 12-month follow-up, each patient was evaluated using the range of motion (ROM) assessment and the Constant–Murley Score (CMS). Patients were examined using the ShowMotion 3D kinematic tracking system (NCS Lab, Modena, Italy), which uses wireless wearable noninvasive magnetic and inertial measurement units sensors to assess the three-dimensional kinematics of the shoulder. For each plane of elevation (ie, flexion and abduction), the SHR was described by 3 scapulothoracic rotations (ie, protraction–retraction, mediolateral rotation, and posterior–anterior tilting) as a function of humeral anteflexion or humeral abduction. Results Active flexion and external rotation ROM showed statistically significant improvement ( P = .039 and P = .006, respectively). CMS pain, strength, and total showed statistically significant improvement ( P = .039 and P = .006, respectively). All the patients showed a nonstatistically significant difference of the SHR along the entire ROM between pre- and postoperative evaluation. The P value in flexion and abduction was >.05; the only statistically significant value was on tilt at 60° in flexion ( P = .044). Conclusion A persistent scapular dyskinesis was observed after arthroscopic rotator cuff repair. Despite a statistically significant improvement reported for active flexion, active external rotation, and for the total CMS, scapular dyskinesis is not resolved with surgery and may contribute to worse long-term outcomes. Further biomechanical and clinical research studies are needed to define specific rehabilitation programs, to maximize outcomes, and to prevent possible cause of reinjury of the rotator cuff repaired.
Copyright remains with the authors and publisher.