PRP injection offers little to chronic Achilles tendinopathy patients.

http://jama.ama-assn.org/cgi/content/short/303/2/144?home

Platelet-Rich Plasma Injection for Chronic Achilles Tendinopathy
A Randomized Controlled Trial
Robert J. de Vos, MD; Adam Weir, MBBS; Hans T. M. van Schie, DVM, PhD; Sita M. A. Bierma-Zeinstra, PhD; Jan A. N. Verhaar, MD, PhD; Harrie Weinans, PhD; Johannes L. Tol, MD, PhD
JAMA. 2010;303(2):144-149.
Context 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, placebo-controlled 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 Assessment-Achilles (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 between-group 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.
Trial Registration clinicaltrials.gov Identifier: NCT00761423
Author Affiliations: Departments of Orthopedics (Drs de Vos, van Schie, Verhaar, and Weinans) and General Practice (Dr Bierma-Zeinstra), Erasmus University Medical Center, Rotterdam; Department of Sports Medicine, The Hague Medical Center Antoniushove, Leidschendam (Drs Weir and Tol); and Department of Equine Sciences, Utrecht University, Utrecht (Dr van Schie), the Netherlands.