The Relationship Between Platelet-Rich Plasma (PRP) Therapy and Healing of Achilles Tendinopathy: A Systematic Review

Abstract

Introduction

Achilles tendinopathy (AT) is one of the most prevalent overuse musculoskeletal injuries, affecting up to 10% of recreational runners and 24% of elite athletes.^1,2 Platelet-Rich Plasma (PRP) has been proposed as a regenerative adjunct to accelerate tendon healing by delivering supraphysiologic concentrations of growth factors—including Transforming Growth Factor-β1 (TGF-β1), Vascular Endothelial Growth Factor (VEGF), Platelet-Derived Growth Factor (PDGF), and Epidermal Growth Factor (EGF)—directly to the degenerative tendon matrix.³

Methods

A systematic literature search was conducted following PRISMA 2020 guidelines. Randomized controlled trials (RCTs), etc evaluating PRP injection versus placebo (saline), sham injection, eccentric exercise alone, high-volume injection (HVI), or other comparators in patients with clinically and/or ultrasonographically confirmed AT were included.

Results

Sixteen primary studies (N = 1,482 participants) and five meta-analyses/systematic reviews met inclusion criteria. Primary RCTs included landmark trials from JAMA (de Vos et al., 2010; Kearney et al., 2021)^4,5, American Journal of Sports Medicine (Boesen et al., 2017; Krogh et al., 2016)^6,7, and Clinical Orthopaedics and Related Research (Zhang et al., 2018)⁸. Meta-analyses identified no statistically significant superiority of PRP over placebo for VISA-A at 6, 12, or 24 weeks in the majority of trials. However, PRP combined with eccentric exercise demonstrated a statistically significant superiority over eccentric exercise alone in VAS pain reduction at 12 weeks (MD = 11.30, 95% CI: 7.33–15.27; p<0.00001; I²=0%)⁹. Leukocyte-rich PRP (LR-PRP) formulations exhibited superior outcomes compared to leukocyte-poor PRP (LP-PRP) for pain reduction in general tendinopathy. Tendon thickness reduction at 24 weeks was significantly greater in the combined PRP+eccentric group versus placebo (p<0.05). Adverse event rates were higher for PRP than saline (complication rate 41.1% vs. 33.7%, p<0.01) but were predominantly mild, transient injection-site pain. GRADE certainty of evidence was rated as Low to Moderate for most outcomes.

Discussion

The body of evidence consistently demonstrates that a single PRP injection does not confer a clinically meaningful advantage over placebo in terms of VISA-A or global function at standard follow-up intervals when added to eccentric exercise. However, specific subgroup analyses suggest that repeated (multiple) PRP injections and LR-PRP formulations may yield superior outcomes in the intermediate term, particularly for pain reduction. Methodological heterogeneity—encompassing variations in PRP preparation protocols, platelet concentration, leukocyte content, injection technique, volume, concomitant rehabilitation, and outcome assessment timepoints—constitutes the major limiting factor precluding definitive conclusions.

Conclusion

Current moderate-quality evidence does not support routine PRP injection as a superior alternative to placebo or standard eccentric exercise rehabilitation for chronic AT. Nevertheless, PRP remains a safe, autologous biological adjunct with mechanistically plausible pro-regenerative properties. Future large-scale, well-powered RCTs with standardized PRP protocols, adequate control groups, and long-term follow-up (≥24 months) are required before definitive clinical recommendations can be made.