Clinical outcomes of intra-articular platelet-rich plasma injection in knee osteoarthritis

Osteoarthritis (OA) of the knee is a prevalent condition that significantly impacts the quality of life for millions of individuals worldwide. As a leading cause of disability, its effective management is crucial. Intra-articular injections of platelet-rich plasma (PRP) have gained attention as a potential treatment, offering a biologic approach to enhance cartilage repair and reduce inflammation. This study evaluated the short-term clinical outcomes observed following intra-articular PRP injections in patients with knee OA, focusing on pain relief and functional improvement. The study involved 59 unique participants contributing 61 knees diagnosed with KL grade II and III knee OA who received PRP injections. Patients were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Visual Analogue Scale (VAS) scores. Evaluations were conducted at baseline and two, four, and six months post-injection to assess pain relief and functional improvement. Significant improvements in VAS and WOMAC scores were observed during follow-up after PRP injection. Greater improvements were observed among knees with KL grade II OA compared with KL grade III OA during follow-up. Injection-site pain occurred in nine knees from nine participants and resolved with oral paracetamol. No additional local or systemic adverse events were observed during follow-up. Participants demonstrated significant improvements in pain and functional scores during the six-month follow-up period after receiving intra-articular PRP injections ( p < 0.001 for all time points, with effect sizes ranging from 1.25 to 2.87). Because this was an uncontrolled prospective cohort study, these findings should be interpreted as observed clinical improvements following PRP treatment rather than definitive evidence of treatment efficacy or causation. Randomized controlled studies with longer follow-up and control groups are required to determine the causal effect and comparative effectiveness of PRP. The study was retrospectively registered at ClinicalTrials.gov (Identifier: NCT07828561) on 10th September 2026. Registration occurred after completion of recruitment and data collection.