Published online Apr 18, 2020. doi: 10.5312/wjo.v11.i4.206
Peer-review started: September 17, 2019
First decision: December 23, 2019
Revised: January 15, 2020
Accepted: February 8, 2020
Article in press: February 8, 2020
Published online: April 18, 2020
Rotator cuff tear (RCT) is referred to the injury of one or more of the tendons or muscles of the rotator cuff and is known as one of the most common causes of shoulder pain and disability among the adult population. Identification of risk factors, which predisposes the incidence of RCT, is of considerable importance in the prevention of such injuries.
Earlier investigations have revealed an association between shoulder gradient and shoulder pathologies, such as shoulder impingement syndrome. We hypothesized that the shoulder gradient might also predispose the occurrence of RCT.
In this study, we evaluated the association between the shoulder gradient and RCT incidence to find whether the shoulder gradient could be regarded as a risk factor for RCT or not.
Sixty-one patients with a confirmed diagnosis of RCT were identified as eligible for the study. On the anteroposterior radiograph of the shoulder, we evaluated the gradient of both shoulders in adduction and neutral rotation positions. The gradient difference between affected and unaffected shoulders was also calculated.
The mean shoulder gradient was 14.11º ± 2.65º for the affected shoulder and 15.8º ± 2.2º for the unaffected shoulders. Based on these results, a gradient difference of 1.15º ± 1.82º was found between the injured and non-injured shoulders. This difference was not statistically significant (P = 0.41). The shoulder gradient was not correlated with the pain level of the patients (r = 0.109, P = 0.071), as well as with other clinical and demographic characteristics of the patients.
Based on the results of this study, there is no association between the shoulder gradient and incidence of RCT. Moreover, the shoulder gradient is not associated with the pain level of RCT patients.
Future large-scale studies allowing the elimination of confounding factors in a multivariate analysis will shed more light on the role of shoulder gradient in the incidence of RCT.