Abstract / Summary
Background/Objectives: This study aimed to compare the effects of manual therapy (MT) and corticosteroid injection (CI) on shoulder muscle tone, function, and health-related quality of life (HRQOL) in patients with chronic shoulder pain (CSP) and to identify the muscle-tone change most strongly associated with functional recovery. Methods: In this quasi-experimental, non-randomized study, 44 patients with CSP lasting >6 months were allocated to MT (n = 22) or CI (n = 22) according to the treating physician’s judgment. Each group received the assigned intervention for 4 weeks, together with conventional physical therapy and a home-based exercise program. Muscle tone (upper trapezius, anterior deltoid, posterior deltoid, and latissimus dorsi [LD]), the Patient-Specific Functional Scale (PSFS), and HRQOL were assessed at the baseline and at 2 and 4 weeks. Exploratory linear regression analyses examined factors associated with changes in PSFS scores. Results: Both groups showed significant improvements in muscle tone, shoulder function, and HRQOL. Compared with CI, MT produced greater improvements in muscle tone, PSFS scores, and EuroQol Visual Analogue Scale (EQ VAS) scores. All participants achieved the PSFS minimal important change of ≥2 points. The proportion of participants achieving a post hoc exploratory threshold of ≥5 points was higher with MT than with CI (90.9% vs. 13.6%). In separate regression models adjusted for treatment group, changes in LD tone and EQ VAS were each associated with the change in PSFS score. Conclusions: Both groups showed short-term improvements, with greater gains in muscle-tone measures and function in the MT group. These findings do not establish that MT itself is superior to CI, and the exploratory LD association requires confirmation.