Platelet rich plasma injection in knee osteoarthritis: results after four years.

Background Knee osteoarthritis (KOA) is a progressive degenerative disease and a leading cause of disability worldwide. Intra-articular injection of platelet-rich plasma (PRP) is still a debatable symptomatic treatment and has provided multiple publications in literature with mixed results. Aim of the work To evaluate the short and long term effects of intra-articular injection of PRP on pain and functional status of the knee joint as measured by the Lysholm questionnaire and visual analogic pain scale (VAS). Patients and methods Twenty-one patients with primary Kellgren-Lawrence grade 3 KOA were assessed using the Lysholm questionnaire and the visual analogue scale for pain (VAS). A single PRP injection was administered, followed by reassessment of VAS at the first, fourth and eighth weeks after the injection. After eight weeks, patients were assessed with VAS and Lysholm questionnaire. In order to evaluate the long term effect of this single injection, we reassessed the patients four years after the injection using the same method. Results Fifteen females (71%) and six males (29%) with mean age 60 years (ranging from 44 to 76 years) were enrolled. After a single PRP injection, there was significant improvement in Lysholm and VAS. Before the injection, VAS medium score was 7 (ranging from 5 to 9) and we observed improvements in all assessments at the first (medium VAS 2), fourth (medium VAS 2) and eighth week (medium VAS 2) post injection and was still better than the pre injection score after 4 years (medium VAS 4). This was also observed in Lysholm score. The pre injection score was 41; at 8 weeks, 84; at 4 years, 66. Conclusion PRP injection achieves good results in the symptomatic treatment of Kellgren-Lawrence grade 3 KOA. This study confirmed that a single PRP injection can provide a long-term effect in pain reduction and functional status improvement in KOA, despite the progression of the disease. Further studies with more patients and randomized double blinded controlled studies are recommended to confirm these results.