Protocol for a multicentre randomised triple-blind controlled trial assessing the clinical efficacy of intra-articular platelet-rich plasma injections versus placebo in symptomatic knee osteoarthritis (PIKOA)

Introduction: Despite their exponential use, intra-articular (IA) injections of platelet-rich plasma (PRP) are not part of the recommended treatments for knee osteoarthritis (OA) by most international scientific societies. The most recent clinical trials have shown conflicting results, and some did not find any clinical benefit of PRP injections. The PRP In Knee OsteoArthritis (PIKOA) trial was designed to assess the clinical efficacy and structural benefit of IA injections of PRP vs saline solution (placebo) in symptomatic knee OA.

Methods and analysis: PIKOA is an academic phase 3, superiority, triple-blind (patients, investigators and injectors), multicentre, randomised placebo-controlled trial (1:1 ratio). It compares the efficacy of 1 weekly IA injection of 5 mL PRP or placebo (saline solution) for 3 weeks with a 6-month follow-up. The trial will enrol 210 participants ≥40 years old with symptomatic and moderate radiographic knee OA (Kellgren and Lawrence grade 2 or 3). PRP is prepared with the A-CP-Kit-T (20 mL) kit and its cellular composition is characterised for each patient. The main objective is to compare change in pain on a 0 mm to 100 mm visual analogue scale (VAS) between W0 and W14. The secondary objectives are to compare the two groups in terms of decrease in VAS pain, Western Ontario and McMaster Universities Osteoarthritis Index total score and subscores, analgesics consumption, OMERACT-Osteoarthritis Research Society International responder rate and improvement in quality of life measured by the EQ-5D-5L score. All these criteria are assessed at W8, W14 and W26. The decrease in serum Coll2-1 and Coll2-1 NO₂ levels (catabolic markers, reflecting cartilage destruction or joint inflammation) and increase in N-propeptide of cartilage IIA level (reflecting cartilage formation) are assessed at W8 and W14. Adverse events and study withdrawals are collected during the study.

Ethics and dissemination: Ethics approval was obtained from the Nord Ouest ethical committee (2021-A00742-39). All participants need to provide written informed consent. The findings will be published in peer-reviewed journals.

Trial registration number: NCT05378815 (ClinicalTrials.gov); pre-results.Protocol version and number: V.3 of 17 July 2023.