Leukocyte-poor platelet-rich plasma is more effective than the conventional therapy with acetaminophen for the treatment of early knee osteoarthritis.

Abstract

Knee osteoarthritis (OA) is a degenerative and progressive articular cartilage disease. Infiltration of autologous platelet-rich plasma (PRP) has been proposed as a therapeutic alternative due to the content of biologically active cytokines in PRP. We aimed to compare the clinical response of acetaminophen and intra-articular leukocyte-poor PRP (LP-PRP) in early knee OA. A total of 65 patients with clinically and radiographically documented knee OA (grade 1-2) were analyzed. Patients were randomized into two groups: 32 were treated with acetaminophen (500mg/8h) over 6weeks, and 33 received three intra-articular injections of autologous LP-PRP (once every 2weeks). All patients were evaluated by the Visual Analogue Scale (VAS), the Western Ontario and McMaster Universities (WOMAC) score, and the SF-12 health survey at baseline and 6, 12, and 24weeks of follow-up. All LP-PRP preparations were analyzed for the platelet, leukocyte, IL-1ra, and TGF-β concentrations. The decrease in the VAS pain level in the LP-PRP group was greater than that in the acetaminophen group (p<0.05). Patients treated with LP-PRP showed a sustained improvement in knee function at week 24 (p<0.01). The SF-12 results only indicated an improvement in quality-of-life in the LP-PRP group at 6, 12, and 24weeks of follow-up (p<0.01). Both IL-1ra and TGF-β were detected in the LP-PRP samples (313.8±231.6 and 21,183.8±8556.3pg/mL, respectively). Treatment with LP-PRP injections resulted in a significantly better clinical outcome than did treatment with acetaminophen, with sustained lower EVA and WOMAC scores and improvement in quality-of-life (higher SF-12 score). Therapy with LP-PRP may positively modify the inflammatory joint environment by counteracting IL-1β action.