Leukocyte and Platelet Rich Plasma (L-PRP) Versus Leukocyte and Platelet Rich Fibrin (L-PRF) For Articular Cartilage Repair of the Knee: A Comparative Evaluation in an Animal Model

Background: Articular cartilage injuries of the knee are among the most debilitating injuries leading to osteoarthritis due to limited regenerative capability of cartilaginous tissue. The use of platelet concentrates containing necessary growth factors for cartilage healing has recently emerged as a new treatment method. Objectives: The efficacy of two types of different platelet concentrates were compared in the treatment of acute articular cartilage injuries of the knee in an animal model. Materials and Methods: Eighteen adult Iranian mixed breed male dogs were used to conduct this experimental study. Full thickness articular cartilage defects (diameter 6 mm, depth 5 mm) were created in the weight bearing area of femoral condyles of both hind limbs in all dogs (n = 72). Twelve dogs were randomly selected to receive treatment and their right and left hind limb defects were treated by L-PRP and L-PRF implantation respectively, while no treatment was undertaken in six other dogs as controls. The animals were euthanized at 4, 16 and 24 weeks following surgery and the resultant repair tissue was investigated macroscopically and microscopically. At each sampling time, 4 treated dogs and 2 control dogs were euthanized, therefore 8 defects per group were evaluated. Results: Mean macroscopic scores of the treated defects were higher than the controls at all sampling times with significant differences (P < 0.05) observed between L-PRF treated and control defects (10.13 vs. 8.37) and L-PRP treated and control defects (10 vs. 8.5) at 4 and 16 weeks, respectively. A similar trend in mean total microscopic scores was observed with a significant difference (P < 0.05) between L-PRP treated and control defects at 4 (9.87 vs. 7.62) and 16 (13.38 vs. 11) weeks. No significant difference was observed between the platelet concentrate treated defects in either mean macroscopic scores or mean total microscopic scores. Conclusions: Both L-PRP and L-PRF could be used to effectively promote the healing of articular cartilage defects of the knee.