Nine studies (6 randomized controlled trials and 3 prospective comparative studies) were selected to examine the effects of leukocyte-poor platelet rich plasma and leukocyte-rich platelet rich plasma in knee osteoarthritis treatment. Due to the presence of only one direct comparison between LP-PRP and LR-PRP at the time of the study, studies which compared either to hyaluronic or placebo were included, and network meta-analysis was undertaken. Primary outcome was the incidence of local adverse events, while secondary efficacy outcomes included the change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and International Knee Documentation Committee (IKDC) scores. Incidence of local adverse events was higher with LP-PRP or LR-PRP compared to HA or placebo, and both were ranked at approximately 20% of being the best treatment for the outcome. Nevertheless, the difference between LP-PRP and LR-PRP for incidence of local adverse events was not significant. LP-PRP was ranked number one when considering effect on change in WOMAC, with a 98% probability of being considered the best treatment for the outcome.