Collagen injections versus dry needling in the treatment of chronic supraspinatus tendinopathy: a randomized controlled trial

Purpose This randomized controlled study compares ultrasound-guided collagen injections (USG-CI) vs. ultrasound- guided dry needling (USG-DN) for treating chronic supraspinatus tendinopathy. Methods Forty patients were randomly divided into two groups of 20 each. Group A received four weekly collagen injections, while Group B underwent two dry needling sessions four weeks apart. Both groups followed the same rehabilitation protocol. Outcomes were measured using the Constant-Murley Score (CMS), the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH) questionnaire, and Ingwersen ultrasound score at baseline, 2 weeks, 1 month, and 3 months. Results While no significant differences were found at 2 weeks, group A showed statistically significant improvements at 1 and 3 months compared to group B in both CMS and DASH scores. Ultrasound evaluation also revealed better structural improvement in group A. Both treatments improved pain and functionality, but USG-CI demonstrated a statistically significant advantage in clinical scores and tendon morphology at three months. The superiority of collagen injections may be attributed to their ability to stimulate tenocyte proliferation, endogenous collagen synthesis, and restoration of collagen fibers in damaged tendons. While USG-DN also showed therapeutic effects through induced bleeding and growth factor release, it was less effective overall. Conclusions Our findings suggest that U S G - CI could be a safe and feasible treatment for supraspinatus tendinopathy. The future development of our study could be a predictive patient profiling, concomitant imaging and objective outcome measures to allow identifying patients most suitable for USG-CI. Our study has some limitations, so further studies are required to confirm these preliminary data.