111 patients with either unilateral or bilateral hip osteoarthritis were randomized to be treated with one of three injection protocols; platelet rich plasma, hyaluronic acid, or combined platelet rich plasma and hyaluronic acid. Patients were administered three weekly intra-articular injections of the allocated treatment, were followed-up for 12 months post-injection and assessed clinically using a visual analog scale for pain, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Harris Hip Score (HHS). Results demonstrated significantly lower pain in the PRP group compared to the other two groups at 2, 6, and 12 months, as well as significantly higher WOMAC scores at 2 and 6 months.