Injections of platelet-rich plasma are becoming increasingly applied in clinical practice for a number of indications, yet little high-quality systematic study of efficacy has been conducted. Platelets are a source of growth factors involved in tissue repair, supporting their application in injuries and wound healing. Here, de Vos et al (JAMA 2010; 303(2): 144) report the findings of a randomized controlled double-blind trial of platelet-rich plasma injection for the treatment of chronic Achilles tendinopathy.
Patients with untreated Achilles tendon thickening and pain lasting for at least two months were randomized to ultrasound guided injection of platelet-rich plasma or placebo injection of saline. Patients with other musculoskeletal conditions, tendon rupture, or insertional tendinopathy were excluded. Patients, clinical assessors, data analysts, and the practitioner performing the injection were unaware of treatment allocation. All patients underwent similar post-injection rehabilitation exercises. Follow-up clinical assessments were performed at 6, 12, and 24 weeks post-injection, with the primary outcomes at 24 weeks. The Victorian Institute of Sports Assessment-Achilles (VISA-A) score was the primary outcome measure.
A total of 54 participants (27 per group) were randomized. All completed the study to 24 weeks. The average age of participants was 50 years, half were female, and most (>80%) were active in sports. Clinical characteristics were balanced between groups. There were no adverse events in either group. VISA-A score improved in both groups, with no difference in VISA-A score between groups at 24 weeks, even after adjusting for baseline VISA-A score or duration of symptoms. Secondary outcomes (satisfaction, return to activities) were also not different between treatment allocation at 24 weeks.
Platelet-rich plasma injection was not superior to placebo in the treatment of chronic Achilles tendinopathy
As with recent controlled trials of vertebroplasty vs. sham, this trial demonstrates the importance of conducting randomized trials with comparison to an meaningful control in disorders in which the natural history of the disease improves or fluctuates. The preparation and injection of platelet-rich plasma is expensive, and not frequently covered by insurance. Patients who have injection of platelet-rich plasma recommended for treatment of various conditions should inquire of their providers about the evidence base, expected outcomes, out-of-pocket cost, and thoroughly discuss all treatment alternatives.