Effects of platelet-rich plasma on subchondral bone marrow edema and biomarkers in synovial fluid of knee osteoarthritis

Background The aim of the study was to investigate the effect of platelet-rich plasma (PRP) on subchondral bone marrow edema (BME) and the level of biomarkers in synovial fluid of the knee osteoarthritis. Methods Eighty-one patients with symptomatic knee osteoarthritis were randomly divided into two groups according to the number of inpatients. Forty-five cases were treated with intra-articular injection of PRP (PRP group), 36 cases were treated with sodium hyaluronate (SH group), and the clinical effects were evaluated using the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. The changes of subchondral BME were assessed by magnetic resonance imaging (MRI) before and after treatment. The levels of TNFα, IL-6, MCP-1, MMP-1, MMP-3, and MMP-9 in synovial fluid were also detected. Results All the patients completed the corresponding treatment and were followed up for 12 months without serious complications. After the treatment, the VAS and WOMAC scores of the two groups were significantly decreased, and the difference was statistically significant at different time points (P < 0.05). The VAS and WOMAC scores of the PRP group were better than those of the SH group (P < 0.05). MRI showed that the subchondral bone edema of the two groups were reduced in varying degrees, and the reduction was more noticeable in the PRP group (P < 0.05). The levels of TNFα, IL-6, MCP-1, MMP-1, MMP-3, and MMP-9 in two groups were decreased, and the difference was statistically significant at different time points (P < 0.05). However, the levels of TNFα, IL-6, MCP-1, MMP-1, MMP-3, and MMP-9 in the PRP group were significantly lower than those in the SH group (P < 0.05). Conclusions Intra-articular injection of PRP can significantly reduce the subchondral BME and the level of biomarkers in synovial fluid of the symptomatic knee osteoarthritis.