Does Bone Marrow Edema Influence the Clinical Results of Intra-Articular Platelet-Rich Plasma Injections for Knee Osteoarthritis?

Platelet-rich plasma (PRP) is increasingly used for the intra-articular treatment of knee osteoarthritis (OA). However, clinical studies on PRP injections reported controversial results. Bone marrow edema (BME) can cause symptoms by affecting the subchondral bone and it is not targeted by intra-articular treatments. The aim of this study was to investigate if the presence of BME can influence the outcome of intra-articular PRP injections in knee OA patients. A total of 201 patients were included in the study, 80 with and 121 without BME at the baseline MRI. BME area and site were evaluated, and BME was graded using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Patients were assessed with International Knee Documentation Committee (IKDC) score Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, the EuroQol-Visual Analogue Scale (EQ-VAS), and the Tegner score at baseline, 2, 6, and 12 months. Overall, the presence of BME did not influence the clinical results of intra-articular PRP injections in these patients treated for knee OA. Patients with BME presented a similar failure rate and clinical improvement after PRP treatment compared to patients without BME. The area and site of BME did not affect clinical outcomes. However, patients with a higher BME grade had a higher failure rate.