Efficacy of intra-articular injection of combined platelet-rich-plasma (PRP) and hyaluronic acid (HA) in knee degenerative joint disease: a prospective, randomized, double-blind clinical trial

Purpose: Intra-articular injections of hyaluronic acid (HA) and platelet-rich plasma (PRP) represent promising options in the conservative treatment of early stages of knee osteoarthritis (OA). Although the combined use of these two compounds seems to have a synergistic effect in pre-clinical studies, few clinical trials compared the association of PRP and HA with PRP and HA alone. The aim of study is to evaluate the efficacy of combined intra-articular injections of PRP and HA in the treatment of mild to moderate knee OA, compared to PRP and HA alone.

Methods: One hundred and seventy-four patients were prospectively enrolled and randomized to undergo three intra-articular injections of either HA or PRP or the combination of PRP and HA with a two-week interval period. Patients were evaluated before treatment and after 3, 6, and 12 months using Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score, Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee subjective score, Visual Analogue Scale and TEGNER Activity Scores.

Results: All the treatments proved to be effective in reducing pain and improving joint function. The analysis of covariance did not show statistically significant differences among the three groups for any of the investigated outcome parameters after 6 and 12 months (WOMAC: p = 0.45 and p = 0.64, respectively). No significant differences were found in terms of adverse events (p = 0.49) and painkiller use (p = 0.28 and p = 0.56, respectively) among the three groups.

Conclusion: This multicenter, prospective, randomized, double-blind controlled trial revealed that intra-articular injections of PRP + HA, PRP, or HA represent a safe and viable treatment with comparable efficacy in terms of pain relief and functional outcomes in mild to moderate knee OA.