title: 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.
abstract: 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.
  
  
  OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Veterinary Clinical Sciences, Tabriz Branch, Islamic Azad University, Tabriz, IR Iran.
authors.forename: Davoud
authors.initials: D
authors.lastname: Kazemi
authors.affiliation: Department of Pathology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, IR Iran.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Fakhrjou
keywords: Articular Cartilage; Cartilage; Dogs; Knee Joint; Platelet-Rich Plasma