The scapula plays multiple roles that improve shoulder complex function. Its synchronous rotation with the humerous allows maintaining the glenoid alignment to the arm during shoulder motion. Moreover, it serves as stable base for rotator cuff (RC) muscles. Altered scapular position or motion is defined as Scapular Dyskinesis (SD). SD influences three-dimensional glenohumeral angulation, glenohumeral strain, subacromial space, shoulder muscle activation and strength. The high incidence of SD in patients with shoulder diseases suggests a relationship between altered scapular kinematics and shoulder pathologies. SD may increase the functional deficit associated to RC diseases because scapula and muscles work in synergy. Despite the high incidence of SD in patients with RC diseases, clinical presentation of those patients has not been described in terms of clinical scores and range of motions (ROMs).
The primary aim of this study is to evaluate differences in clinical presentation of patients with RC tears with and without SD.
52 patients with RC tears were enrolled. Patients were screened for SD using a standardized physical examination and divided into two groups: abnormal SD group and normal SD group. Demographic data (age, weight, height and sex), RC size, clinical scores (CMS, ASES, DASH, and OSS) and range of motions (ROMs) were evaluated.
The two groups were homogeneous in terms of age, weight, height, and tear size. The two groups showed statistically significant difference in OSS (p=.032), but not in ASES (p =.06), CMS (p =.127) and DASH scores (p = 0,62). There were statistically significant differences between the two groups in terms of ROMs except in internal rotation at 90° (p =.1) and 0° (p =.857).
The SD is a dysfunctional movement of the scapula identified in several shoulder injuries, such as RC tears. The influence of SD in RC tears is still not clarified. It can be considered as a cause, an effect or a compensation. The present cohort study analysed the clinical implications of SD in patients with RC tears. Clinical scores and ROMs were evaluated in RC tears patients with abnormal or normal SD. The two groups showed statistically significant differences in OSS and ROMs (flexion, extension, abduction and external rotation). A comprehensive evaluation of shoulder kinesis in patients with RC tears is useful to understand the impact of SD and can guide the treatment strategy.