PLATELET-RICH PLASMA (PRP) INTRAARTICULAR INJECTION FOR OSTEOARTHRITIS OF THE KNEE - DOES IT AFFECT ARTICULAR CARTILAGE CONTENT? A SYSTEMATIC REVIEW AND META-ANALYSIS

Introduction/Aim: Platelet Rich Plasma (PRP) is increasingly used in the management of knee osteoarthritis. This study aimed to assess the effect of PRP on knee articular cartilage content (thickness and/or volume) and establish if there is a correlation between changes in cartilage and clinical outcomes in patients with knee osteoarthritis. 

Methods: A systematic review was performed following the Cochrane methodology in four online databases. Studies were included if they reported on cartilage content with MRI or Ultrasound before and after the injection. A random-effects model meta-analysis was performed. Correlation between the articular cartilage change and clinical outcomes was evaluated.

Results: 11 studies (n=786) from 1,453 records met the inclusion criteria (Figure 1): five RCTs (n=444), one prospective (n=50), one retrospective cohort (n=68), and four case-series (n=224). The PRP treatment protocol varied widely. Follow-up ranged from 6-12 months. Eight studies reported increase in cartilage content in the PRP group as compared to control (four showing significant difference). In meta-analysis: PRP treatment was not associated with a significant increase in cartilage thickness in either femoral condyle in isolation (Figures 2 and 3), or in the overall cartilage content (4 studies, n=187, Hedges’ g: 0.079; 95%CI: 0.358-0.516; p=0.723). Meta-analysis of 3 RCTs (n=112) showed no significant difference in the change of overall cartilage content with PRP injections compared with no PRP (Hedges’ g: 0.217; 95%CI: -0.177 – 0.611; P=0.281). There was no correlation between changes in cartilage and clinical outcomes following PRP treatment.

Conclusions: Treatment of knee osteoarthritis with PRP is not associated with a significant increase in articular cartilage content and any effect on cartilage post-PRP treatment is not associated with better clinical outcomes. A multi-centre, adequately powered RCT, with a standardised preparation/administration protocol assessing the long-term effect of PRP in knee osteoarthritis with high-resolution MRIs is needed to guide clinical care.