Adjunct Tendon Vibration and Bone Outcomes in Older Adults with Osteoporosis: A 12-Month Prospective Cohort Study

Background/Objectives: To evaluate the association between adjunct tendon vibration and changes over 12 months in dual-energy X-ray absorptiometry (DXA)-derived bone mineral density (BMD) T-score and bone turnover markers in older adults with osteoporosis receiving standard care in a non-randomised controlled cohort study. Methods: This 12-month prospective non-randomised controlled cohort study included 100 adults aged ≥60 years with DXA-confirmed osteoporosis recruited from orthopaedic clinics in the Greater Thessaloniki area. Fifty participants received adjunct tendon vibration therapy in addition to usual care, while 50 received usual care alone. Usual care consisted of calcium and vitamin D supplementation. The primary outcome was post-intervention BMD T-score, analysed using analysis of covariance (ANCOVA) adjusted for baseline T-score. Secondary outcomes included changes in bone turnover markers and calcium/phosphate metabolism. Sensitivity analysis was conducted using a linear mixed-effects model with repeated BMD measurements. Results: Baseline characteristics were comparable between groups. Over 12 months, the intervention group showed greater improvement in BMD T-score than controls (median change 0.90 [0.70-1.00] vs. -0.10 [-0.10-0.10], p < 0.001). The adjusted between-group difference was 0.871 (95% CI 0.773-0.968; p < 0.001). Results remained consistent after adjustment for age and sex. The mixed-effects model confirmed a significant group × time interaction (β = 0.922, 95% CI 0.806-1.038; p < 0.001). Bone resorption markers decreased more in the intervention group. The magnitude of the observed BMD improvement (~0.9 T-score units) is notable for a non-pharmacological intervention and should be interpreted cautiously. Conclusions: Adjunct tendon vibration was associated with a more favourable BMD trajectory and changes in bone turnover markers in older adults with osteoporosis receiving standard care. Given the non-randomised design and potential residual confounding, these findings should be interpreted as associative rather than causal.