Thoracic spine manipulation in individuals with subacromial impingement syndrome does not immediately alter thoracic spine kinematics, thoracic excursion, or scapular kinematics: A randomized controlled trial

STUDY DESIGN: Randomized controlled trial. OBJECTIVES: To determine if thoracic spinal manipulative therapy (SMT) alters thoracic kinematics, thoracic excursion, and scapular kinematics compared to a sham SMT in individuals with subacromial impingement syndrome, and also to compare changes in patient-reported outcomes between treatment groups. BACKGROUND: Prior studies indicate that thoracic SMT can improve pain and disability in individuals with subacromial impingment syndrome. However, the mechanisms underlying these benefits are not well understood. METHODS: Participants with shoulder impingement symptoms (n = 52) were randomly assigned to receive a single session of thoracic SMT or sham SMT. Thoracic and scapular kinematics during active arm elevation and overall thoracic excursion were measured before and after the intervention. Patient-reported outcomes measured were pain (numeric pain-rating scale), function (Penn Shoulder Score), and global rating of change. RESULTS: Following the intervention, there were no significant differences in changes between groups for thoracic kinematics or excursion, scapular kinematics, and patient-reported outcomes (P>05). Both groups showed an increase in scapular internal rotation during arm raising (mean, 0.9°; 95% confidence interval [CI]: 0.3°, 1.6°; P = .003) and lowering (0.8°; 95% CI: 0.0°, 1.5° ; P = .041), as well as improved pain reported on the numeric pain-rating scale (1.2 points; 95% CI: 0.3, 1.8; P<.001) and function on the Penn Shoulder Score (9.1 points; 95% CI: 6.5, 11.7; P<.001). CONCLUSION: Thoracic spine extension and excursion did not change significantly following thoracic SMT. There were small but likely not clinically meaningful changes in scapular internal rotation in both groups. Patient-reported pain and function improved in both groups; however, there were no significant differences in the changes between the SMT and the sham SMT groups. Overall, patient-reported outcomes improved in both groups without meaningful changes to thoracic or scapular motion.