Effect of single injection of platelet-rich plasma in comparison with corticosteroid on knee osteoarthritis: a double-blind randomized clinical trial

41 patients including 48 knees with Kellgren-Lawrence grade II-III osteoarthritis were randomized to intraarticular injection therapy with either platelet-rich plasma or corticosteroid (methylprednisolone acetate 40mg). Patients were assessed for outcome on the Knee Injury and Osteoarthritis Outcome Score (KOOS), pain on a visual analog scale, performance on a 20-metre walk test, knee range of motion in flexion, and flexion contracture after 2 and 6 months following injection. Findings demonstrated significantly favourable results in the PRP group compared to the CS group for changes in four out of five KOOS scales, VAS pain scores, and 20-metre walk test times. Knee range of motion variables did not significantly differ between groups.