Platelet-rich plasma outcomes in knee osteoarthritis are associated with the amount of total deliverable platelets: A systematic review and meta-analysis

Objective

The goal of this study was to examine if differing platelet counts in platelet-rich plasma (PRP) formulations affected overall pain and function outcomes when compared to hyaluronic acid or placebo control saline injections.

Design/Methods

We conducted a systematic review and meta-analysis (International Prospective Register of Systematic Reviews CRD42022340057) evaluating randomized controlled trials comparing injections of PRP to hyaluronic acid (HA) or saline (NS) control in patients with mild or moderate knee osteoarthritis. All studies used a validated outcome measure that examined pain, function, or overall patient global assessment. Study PRP interventions were subclassified as investigating the total number of platelets delivered in a low dose (1–5 billion total deliverable platelets), moderate dose (5–10 billion total deliverable platelets), or high dose (greater than 10 billion total deliverable platelets) injected into the joint.

Results

A total of 32 trials met inclusion criteria. All three PRP groups had significant improvements in validated patient-reported outcomes when compared to HA. Both the “low” and “high” platelet count groups resulted in a moderate effect size, respectively (standardized mean difference [SMD] = .47; 95% confidence interval [CI] .05–0.89, p < .01; SMD = .68; 95% CI .26–1.09, p < .01). Only the “moderate” (SMD = 1.48; 95% CI .71–2.58 p < .01) platelet count group resulted in large effect size on validated patient-reported outcomes. When compared to NS, all three PRP groups resulted in significant large effect sizes when examining pain reduction.

Conclusions

When compared to HA, PRP with platelet counts between 1 and 10 billion total deliverable platelets may result in a larger decrease in pain symptoms when compared to platelet counts greater than 10 billion at 6 months. In addition, platelet counts between 5 and 10 billion total deliverable platelets may be associated with greater improvement in functional outcomes.

View the full publication here: https://onlinelibrary.wiley.com/doi/10.1002/pmrj.13455

Hooper N, Shapiro S, Paidsetty V, et al. Platelet-rich plasma outcomes in knee osteoarthritis are associated with the amount of total deliverable platelets: A systematic review and meta-analysis. PM&R. 2026; 18(2): 210-222. doi:10.1002/pmrj.13455