Comparative efficacy of platelet-rich plasma monotherapy versus combination therapies for knee osteoarthritis: a systematic review and network meta-analysis

Luan D, Zhang X, Zhang Z, Man X, Bo H · Journal of Orthopaedic Surgery and Research

18 randomized trials and 1,376 participants, comparing intra-articular PRP alone against PRP combined with hyaluronic acid, with mesenchymal stem cells, or with ozone. The network was star-shaped, with PRP alone as the only common comparator. PRP plus hyaluronic acid was the one combination that beat PRP alone, on WOMAC function (MD -6.16, 95 percent CI -9.71 to -2.61, P < 0.001) and on VAS pain (MD -1.01, 95 percent CI -1.57 to -0.44, P < 0.001). Neither PRP plus ozone (WOMAC function MD -9.65, 95 percent CI -20.33 to 1.03; VAS pain MD -0.15, 95 percent CI -1.87 to 1.57) nor PRP plus stem cells separated from PRP alone. The authors are explicit that this is not a null result for ozone: only one small trial contributed to that comparison, the confidence intervals are wide, and they state that the absence of statistical significance cannot be read as evidence of no effect.

Population

18 randomized controlled trials comparing intra-articular PRP alone with PRP combined with hyaluronic acid, mesenchymal stem cells or ozone in adults with knee osteoarthritis, 1,376 participants

Intervention

PRP combined with hyaluronic acid, mesenchymal stem cells or ozone

Comparator

PRP monotherapy

Limitations

The whole ozone comparison rests on a single small trial, which the authors name as the review's most significant limitation, and the resulting estimates are too imprecise to support a claim of equivalence or of inferiority in either direction. The network's star shape means every combination is compared with the others only indirectly, through PRP alone. Where trials reported several follow-up points the longest was taken, so the pooled estimates describe sustained rather than peak effect. Funding was the Tianjin Scientific Research Foundation and the Natural Science Foundation of Inner Mongolia Autonomous Region; the authors declare no competing interests.