Role of shoulder gradient in the pathogenesis of rotator cuff tears.

Abstract

Shoulder gradient has been associated with shoulder pathologies such as shoulder impingement syndrome. To investigate if there is an association between shoulder gradient and incidence of rotator cuff tear (RCT). A total of 61 patients with a confirmed diagnosis of RCT were included in this retrospective study. The anteroposterior radiograph of the shoulder was used to measure shoulder gradient in adduction and neutral rotation positions. The pain level was assessed with the visual analog scale for pain. The mean age of the patients was 55.7 ± 12.3 years. The mean visual analog scale of the patients was 4.1 ± 1.2. The mean shoulder gradient was 14.11º ± 2.65º for the affected shoulder and 15.8º ± 2.2º for the unaffected shoulders. This difference was not statistically significant (P = 0.41). A difference of 1.15º ± 1.82º was found between the injured and non-injured shoulder. No significant association was found between the gradient difference of the shoulder and demographic and clinical characteristics of the patients. Shoulder gradient is not associated with the pathology of RCT. Yet, future studies with more standardization and a larger sample size are needed to investigate the role of shoulder gradient in RCT pathogenesis further.