The relationship between kyphosis, and shoulder pain is unclear, and the effects of kyphosis angle on pain severity, range of motion, isokinetic strength, and upper extremity functionality remain undetermined. This study aimed to investigate the correlation between increased thoracic kyphosis and these factors. Thirty participants with a thoracic hyperkyphosis (a mean thoracic kyphosis angle of 57.47 ± 9.96°) were included in the study. The thoracic kyphosis angle was measured using a manual inclinometer. Shoulder pain severity was assessed with the Visual Analog Scale (VAS), shoulder range of motion was evaluated using a manual goniometer, shoulder isokinetic muscle strength was measured with an isokinetic dynamometer, and upper extremity functionality was assessed using the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire. Significant correlations were observed between thoracic kyphosis angle and both VAS scores and QuickDASH scores. In addition, the thoracic kyphosis angle was negatively correlated with shoulder flexion, abduction, and external rotation range of motion, as well as internal rotation peak torque. No significant correlations were found between thoracic kyphosis angle and the remaining isokinetic muscle strength parameters. Greater thoracic kyphosis angles were associated with increased shoulder pain severity and reduced shoulder flexion, abduction, and external rotation range of motion, decreased internal rotation peak torque, and impaired upper extremity functionality. These findings suggest that interventions aimed at reducing thoracic kyphosis may contribute to improvements in shoulder pain severity and upper extremity function, potentially through enhancements in joint range of motion and isokinetic muscle strength. The protocol is registered with http://clinicaltrials.gov/ (Retrospectively registered, Clinical Trial, NCT07349238.
Yarayan et al. (Fri,) studied this question.