Hyaluronic Acid versus Platelet-Rich Plasma: Double-blind Randomized Controlled Trial Comparing Clinical Outcomes and Intra-Articular Biology for Treatment of Knee Arthritis

OBJECTIVES: Osteoarthritis (OA) is a debilitating disease that, in some form, affects up to 47 million Americans each year and is estimated to affect 67 million by 2030. Hyaluronic acid (HA) is currently utilized as an intra-articular injection for treatment of patients with knee OA. A movement in biochemical research has emerged that focuses on analysis of catabolic and anabolic growth factors of the joint. It is proposed that platelet-rich plasma (PRP) is a biologic alternative to HA that may alter the intra-articular biologic milieu to mitigate the symptoms of OA. The purpose of this double-blind prospective randomized clinical trial is to compare the effects of PRP to HA for the treatment of OA in the knee using validated clinical outcome measures and biologic correlates associated with OA. METHODS: Patients with a minimum of 3 months of symptomatic unilateral knee OA and Kellgren-Lawrence Grade 1-3 OA were randomized into two cohorts. One cohort received three weekly ultrasound-guided injections of HA and the other received three weekly injections of PRP. Patients in both cohorts were seen again at 6-, 12-, and 24-weeks following their index treatment. At each visit, including the treatment and index visits, patients completed a survey that included Lysholm, IKDC, WOMAC, and VAS pain, and underwent a clinical examination. Patients also underwent an ultrasound-guided aspiration of the knee for synovial fluid analysis during each of the treatment visits and at 3-month and 6-month follow up. Synovial fluid was grouped and analyzed via ELISA assay. RESULTS: 111 patients (mean age 56.2 +/- 10.2 years; 53 male, 58 female) met inclusion criteria and were randomized into either the HA or PRP cohort. Eleven (9.9 %) patients were lost to follow-up or unwilling to complete the study. In all of the scales measured, outcomes improved significantly from the index visit at 6 months post treatment (p<.01). PRP had a higher IKDC (p<.02) at 6-month follow up when compared to HA. Patients in the PRP group also reported lower VAS pain scores at 6-month follow up as well (p<.01). The remainder of the outcome measures (Lysholm, WOMAC) demonstrated trends toward greater improvement in the PRP group but did not demonstrate statistical significance. Synovial fluid aspirated was analyzed using ELISA assay for catabolic factors TNF-α, IL-1B/IL-F2, IL-1ra/IL-1F3, IL-6, and CXCL8/IL-8. The PRP cohort had significantly higher IL-6 concentration than the HA cohort at 6-month follow up (p=.02). The PRP and HA groups were not found to have significant differences in concentrations of the other catabolic factors analyzed. CONCLUSION: The findings of this study support a significant improvement of pain and function at 6 months with the use of intra-articular PRP as well as HA for the treatment of OA. Findings further suggest that PRP may be a superior treatment for the active patient with OA.