55 patients with Kellgren-Lawrence grade I-III knee osteoarthritis were randomized to receive either intraarticular injections of autologous platelet-rich plasma (PRP) or hyaluronic acid (HA). The purpose of this study was to compare these two injection therapies in terms of improvement in pain, function, and daily/sports activity, assessed at 3 or 6 months post-treatment. The results of this trial demonstrated comparable improvement between interventions at both time-points. In a subgroup of patients with KL grade II knee OA only, treatment with PRP injections resulted in significantly greater improvement in KOOS activities of daily life scores after 3 and 6 months, pain after 6 months, and sports & recreation activity after 6 months when compared to HA injections.