Do patients with non-traumatic rotator cuff tears differ from healthy individuals in forward head posture, rounded...

Altered cervicothoracic and scapular posture may influence shoulder mechanics, but it remains unclear whether patients with non-traumatic rotator cuff tears show consistent static postural changes. This study compared the craniovertebral angle, rounded shoulder angle, and thoracic kyphosis angle between patients with non-traumatic rotator cuff tears and healthy individuals.

This single-center, cross-sectional observational study included 39 patients with imaging-confirmed, full-thickness, non-massive, non-traumatic rotator cuff tears scheduled for repair and 30 healthy controls. Thoracic kyphosis angle was measured using a digital gravity inclinometer, while craniovertebral angle and rounded shoulder angle were assessed using photogrammetry. Unadjusted between-group comparisons were performed using variance-robust tests as appropriate. Multivariable linear regression with HC3 heteroscedasticity-robust standard errors was treated as the principal inferential analysis and adjusted for age, body mass index, sex, and manual labor status.

Thoracic kyphosis angle was higher in the case group than in the control group (43.80° vs. 40.23°; mean difference = 3.56°; 95% CI, 0.87-6.26; Cohen's d = 0.59; P = 0.011). No statistically significant unadjusted between-group differences were identified for rounded shoulder angle (50.41° vs. 48.88°; mean difference = 1.53°; 95% CI, -2.58 to 5.64; Cohen's d = 0.19; P = 0.458) or craniovertebral angle (50.78° vs. 47.97°; mean difference = 2.81°; 95% CI, -0.70 to 6.33; Cohen's d = 0.40; P = 0.115). After adjustment, case status remained associated with greater thoracic kyphosis angle (B = 3.98°; 95% CI, 1.30-6.66; P = 0.004), whereas the adjusted associations with craniovertebral angle and rounded shoulder angle were not statistically significant.

Patients with non-traumatic, full-thickness, non-massive rotator cuff tears had greater thoracic kyphosis than healthy controls. However, the clinical importance of the approximately 3.6° unadjusted difference remains uncertain because protocol-specific measurement error could not be quantified. No statistically significant adjusted associations were identified for craniovertebral angle or rounded shoulder angle; these null findings should be interpreted cautiously given the study's limited sensitivity to moderate or smaller effects.