Platelet-Rich Plasma Injections for Knee Osteoarthritis with and without Comorbid Rheumatoid Arthritis: A Prospective Case-Control Series- MHSRS 2025

kasper m, smith m, yuan x, noble e, mo

Abstracted accepted for a poster session at the 2025 Military Health System Research Symposium

Introduction: Knee osteoarthritis (KOA) is a degenerative joint disease that is five times more likely to affect the military compared to the general population. Patients who have rheumatoid arthritis (RA), in which proinflammatory cytokines can lead to cartilage damage and bone erosion, can also suffer from KOA. Few studies have investigated the use of platelet-rich plasma (PRP) injections in RA patients. The purpose of this prospective case-control series is to compare the safety and efficacy of PRP injections for KOA in patients with and without RA.

Methods: Military beneficiaries (18+ years) with clinical and radiographic [Kellgren-Lawrence Score ≥ 2] evidence of KOA referred for knee PRP injections were enrolled at a military treatment facility (WRNMMC-2022-0406). The RA cohort additionally met diagnosis criteria with current disease dormancy. Exclusion criteria include prior injections (PRP ≤ 6 months; corticosteroid ≤ 3 months), joint replacement, comorbid autoimmune disease, or medical condition that is a PRP contraindication.

Patient-reported outcome measures included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) collected at baseline, 1-, 3- and 6-months post-procedure..05).

Results: To date, 7 patients have been enrolled (6 KOA, 1 RA+KOA; 42.9% Active duty; 57.1% female). 4 patients (3 KOA, 1RA+KOA) have reached 1-month follow-up for interim analysis, demonstrating symptomatic and functional improvement on their average WOMAC scores (mean ± standard deviation) from baseline to 1-month (24.50 ± 13.82), exceeding the minimal clinically important difference (MCID: 17). Improvement was also seen in all KOOS subscales, although only the pain (8.25 ± 6.13) and activities of daily living (ADL) (17± 9.63) subscales exceeded the MCID threshold (MCID: 8-10). No adverse events (AE) were reported in either group.

Conclusion: Preliminary outcomes of this study demonstrate functional and symptomatic improvement in military beneficiaries with KOA with or without comorbid RA receiving PRP injections. Results of this study will yield additional insight into longer-term functional outcomes and safety of PRP for patients with KOA and RA.