Tendon disorders comprise 30% to 50% of all activity-related injuries; chronic degenerative tendon disorders (tendinopathy) occur frequently and are difficult to treat. Tendon regeneration might be improved by injecting platelet-rich plasma (PRP), an increasingly used treatment for releasing growth factors into the degenerative tendon. Objective To examine whether a PRP injection would improve outcome in chronic midportion Achilles tendinopathy. Design, Setting, and Patients A stratified, block-randomized, double-blind, placebocontrolled trial at a single center (The Hague Medical Center, Leidschendam, the Netherlands) of 54 randomized patients aged 18 to 70 years with chronic tendinopathy 2 to 7 cm above the Achilles tendon insertion. The trial was conducted between August 28, 2008, and January 29, 2009, with follow-up until July 16, 2009. Intervention Eccentric exercises (usual care) with either a PRP injection (PRP group) or saline injection (placebo group). Randomization was stratified by activity level. Main Outcome Measures The validated Victorian Institute of Sports AssessmentAchilles (VISA-A) questionnaire, which evaluated pain score and activity level, was completed at baseline and 6, 12, and 24 weeks. The VISA-A score ranged from 0 to 100, with higher scores corresponding with less pain and increased activity. Treatment group effects were evaluated using general linear models on the basis of intention-to-treat. Results After randomization into the PRP group (n=27) or placebo group (n=27), there was complete follow-up of all patients. The mean VISA-A score improved significantly after 24 weeks in the PRP group by 21.7 points (95% confidence interval [CI], 13.0-30.5) and in the placebo group by 20.5 points (95% CI, 11.6-29.4). The increase was not significantly different between both groups (adjusted betweengroup difference from baseline to 24 weeks, −0.9; 95% CI, −12.4 to 10.6). This CI did not include the predefined relevant difference of 12 points in favor of PRP treatment. Conclusion Among patients with chronic Achilles tendinopathy who were treated with eccentric exercises, a PRP injection compared with a saline injection did not result in greater improvement in pain and activity.
de Vos, R. J., Weir, A., van Schie, H. T. M., Bierma-Zeinstra, S. M. A., Verhaar, J. A. N., Weinans, H., & Tol, J. L. (2010). Platelet-Rich Plasma Injection for Chronic Achilles Tendinopathy. The Journal of the American Medical Association, 303(2), 144-149.