Intra-articular injection of platelet-rich plasma for treatment of knee osteoarthritis: a prospective, randomized, controlled trial

Objective To study the clinical efficacy of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis (KOA) and evaluate whether the age, body mass index and grade of KOA are associated with the treatment outcomes. Methods Using the prospective, randomized, controlled study, 100 KOA patients hospitalized between December 2013 and November 2014 were enrolled. Twenty-eight patients were men and 72 were women. Mean age was 58 years (range, 35-85 years). Degenerative arthritis occurred in 68 patients and traumatic arthritis in 32 patients. Kellgren-Lawrence (K-L) score was grade Ⅱ in 35 patients, grade Ⅱ in 46 and grade Ⅲ in 19. The patients were assigned to receive hyaluronic acid (HA) (HA group, n=50) and PRP (PRP group, n=50) by an intraarticular route once weekly for 3 weeks, according to the random number table. Between-group differences were insignificant in age, gender, body mass index (BMI) and K-L grade. Western Ontario and McMaster Universities Arthritis Index (WOMAC), visual analog scale (VAS) and cartilage lesions score (CaLs) were used for clinical and MRI evaluations. At follow-up evaluation, the effective rate was defined at least 36% improvement from the baseline WOMAC score. Results All patients were followed up for 6 months. The effective rate in PRP group was 84% versus 68% in HA group after the last treatment (P>0.05), and was 60% versus 36% in HA group at the final follow-up (P 0.05), and the area of abnormal signal in subchondral bone and the depth of cartilage lesion gradually decreased in one of them. Follow-up study showed the outcomes had negative correlation with age and K-L grade (P 0.05). Clinical effects in both groups were decreased over time. Conclusions Intraarticular injection of PRP benefits to pain relief, decreased inflammation and tissue repair, and has much better outcome in patients with younger age and lower K-L grade. However, BMI is not associated with the outcome. Key words: Platelet-rich plasma; Knee; Osteoarthritis; Cartilage