Effects of Biomechanical Risk Factors as Cumulative Trauma on Rotator Cuff Tendinopathy in Workers - A Clinical Survey (2018 - 2019)

Cumulative effects of biomechanical risk factors on rotator cuff tendinopathy have not yet been determined. Accordingly, this study aimed to investigate cumulative effects of biomechanical risk factors on rotator cuff tendinopathy among workers.

This descriptive study was conducted on 470 patients suspected of rotator cuff tendinopathy, who referred to the radiology department of Rasool-e-Akram Hospital in Tehran, Iran (July 2018-March 2019). To this end, ergonomic risk factors, including excessive hand raising, repetitive tasks, upper arm flexion, grip force, awkward posture, vibration, abduction, and rotation were evaluated. The subjects were divided into four categories, according to the number of affecting risk factors. Next, univariate and multivariate analyses were performed to identify predictors of rotator cuff tendinopathy. The study data were analyzed by SPSS V24.0.

Risk factors, such as excessive hand raising, repetitive tasks, upper arm flexion, and awkward posture had a significant association with the frequency of rotator cuff tendinopathy (p < 0.05). Our study showed that shoulder tendinopathy had a statistically significant association with having at least one affecting risk factor (OR=3.96 95%CI: 2.26-6.96), two affecting risk factors (OR=6.82 95%CI: 4.13-11.26), three affecting risk factors (OR=10.25 95%CI: 4.35-24.14), and four affecting risk factors (OR=12.61 95%CI: 1.69-93.63).

The existence of more than one mechanical risk factor in the workplace is associated with a greater increase in the possibility of rotator cuff tendinopathy. In most workplaces, there is usually more than one mechanical risk factor, so it is necessary to pay attention to cumulative effects of all of them.