Platelet-rich plasma injections are one of the most common conservative strategies for the management of knee osteoarthritis (OA). However, there are different formulations of PRP, and there is no clarity on which are the ideal characteristics of PRP. The aim of this study was to compare safety and effectiveness of fresh Leukocyte-Rich PRP (LR-PRP) and Leukocyte-Poor PRP (LP-PRP) for the treatment of knee OA.
The study design includes 132 patients with symptomatic knee OA. Randomly, 66 patients receive 3 weekly injections of LR-PRP and 66 patients receive 3 weekly injections of LP-PRP. Patients are prospectively followed at baseline and at 2, 6, and 12 months for the primary outcome, the International Knee Documentation Committee (IKDC) Subjective Score, and secondary outcomes including the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, EuroQol VAS (EQ-VAS), and Tegner score. Up-to-date 25 for LR-PRP and 27 for LP-PRP were evaluated up to 6 months and included in the current analysis.
All the scores significantly improved: the primary outcome improved from 39.9±19.6 to 52.5±25.6 at 6 months in the LR-PRP group compared to 45.7±17.2 to 61.0±13.9 in the LP-PRP group (p<0.005). No differences between groups were observed in terms of improvement of the clinical scores across all follow-up intervals. No severe adverse events were described in either group, while a total of 14 mild adverse events (knee pain or swelling) were reported: 8 for the LR-PRP and 6 for the LP-PRP group. One patient was considered as treatment failure.
The preliminary results of this study suggested that three intra-articular LR-PRP or LP-PRP injections produced similar clinical improvement at 6 months of follow-up in patients with symptomatic knee OA with no inter-group difference in clinical results and adverse events. The presence of leukocytes did not influence PRP effects.