40 patients with knee arthritis (59 knees) undergoing either unilateral or bilateral total knee arthroplasty (TKA) were randomized to either receive or not receive an intraoperative injection of autologous platelet gel (APG). The purpose was to determine the effects of platelet-rich plasma (PRP) with respect to postoperative haemoglobin loss, pain and functional outcomes. Results indicated that the administration of PRP was associated with significantly superior haemoglobin levels, pain levels, and the requirement for narcotics in the postoperative period. These improvements led to better functional outcome up to 3 months postoperatively; however, at 6 months, this statistical significance was lost, and functional scores were similar between groups. Furthermore, there was no significant difference in wound healing between groups.