Six randomized controlled trials with a total of 661 patients with knee osteoarthritis (OA) were randomized to receive platelet-rich plasma injection therapy (PRP; n=338) or hyaluronic acid (HA; n=323). Primary outcomes of interest included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Total Score and WOMAC physical function score. Secondary outcomes of interest included the following: International Knee Documentation Committee (IKDC), EuroQoL visual analogue scale (EQ-VAS), Tegner Activity scores, and the incidence of adverse events. Pooled results revealed that WOMAC total score was statistically significantly in favour of the PRP group compared to HA at 1, 6, and 12 months follow-up (p<0.05 for all). A similar trend was observed for WOMAC physical function score at 12 months follow-up (mean difference [MD] 3.28 [95%CI 2.13, 4.43]). All pooled results for secondary outcomes of interest were not statistically significantly between the PRP and HA groups (p>0.05 for all).