Comparison of the clinical effect of intra-articular injection of platelet-rich plasma and methylprednisolone in primary osteoarthritis of knee: a randomized controlled trial

Background: Osteoarthritis of knee is one of the commonest musculoskeletal disorder causing mobility impairment affecting 3.3% in urban areas and 5.5% in rural areas. Intra-articular injection of Platelet-Rich Plasma (PRP) delivers activated platelets that may reduce inflammation, provide pain relief, improve function and stimulate possible cartilage regeneration at the site of worn cartilage area of the knee.Methods: Eighty patients with primary osteoarthritis of the knee fulfilling inclusion and exclusion criteria were recruited in the study conducted in the Department of Physical Medicine and Rehabilitation, RIMS, Imphal from October 2014 to September 2017. Six ml of PRP prepared by conventional bench top centrifugation system was injected intra-articularly, two weeks apart in the PRP group. Steroid group received 80mg of methylprednisolone, two weeks apart by the same technique. The outcome variables (VAS and WOMAC score) were measured before starting intervention (baseline) and at 8 and 24-weeks post-intervention follow up.Results: Significant improvement seen in VAS, WOMAC-pain, stiffness and physical function and total scores in both the groups at 8- and 24-weeks follow-ups (p˂0.001). Steroid group showed better result than the PRP group in VAS (2.78±0.76 vs 3.58±1.03) and WOMAC-total (30.42±6.85 vs 36.25±10.87) scores at 8 weeks respectively (p˂0.001). But at 24 weeks follow-up, PRP showed significantly more effective than the steroid group in reducing pain (2.0±.0.87 vs 2.45±0.78) and disability (22.95±3.78 vs 25.25±6.67) respectively (p˂0.001).Conclusions: Intra-articular injection of methylprednisolone was found to be more effective in reducing pain and disability in primary knee osteoarthritis of KL grade 2 and 3 at the end of 8 weeks whereas 2 doses of PRP intra-articular injection 2 weeks apart was significantly more effective than methylprednisolone at the end of 24 weeks. However, the long-term benefit of PRP is to be determined by studies with a larger sample size and longer duration of follow-up.