Comparison of Outcomes in Application of Platelet-Rich Plasma (PRP) and Platelet-Rich Fibrin (PRF) in Medial Collateral Ligament Recovery: An Animal Study

Background: The medial collateral ligament (MCL) is one of the most commonly injured ligaments in the knee, accounting for 40% of all knee injuries. Autologous platelet concentrate, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), has been proposed as a novel therapy in ligament injury. Purpose: To evaluate the effectiveness of PRP and PRF in recovery after MCL injury. Study Design: Controlled laboratory study. Methods: This study was a randomized, single-blind, in vivo study on MCL injury in Wistar rats (Rattus norvegicus). Rats that were sick, had a decrease in body weight of >10% after adaptation in the laboratory, or died were excluded. A total of 30 male Wistar rats were divided into 3 groups: group 1 (n=10) received no intervention, group 2 (n=7) received PRP, and group 3 (n=10) received PRF. The variables that were investigated included tensile strength and histopathological appearance. All statistical analysis was performed using SPSS 22.0 using the appropriate test based on the variable. Results: This study found that there was a significant difference in tensile strength across all groups (P = .004), with a significantly higher value in the PRF group compared with the PRP group (mean difference, 2.76; P = .003). There was no significant correlation between tensile strength and ligament length (P = .34). Based on the histopathological data, this study found that PRF resulted in a higher amount of collagen cell orientation when compared with PRP and control (P = .049). Conclusion: This study found that PRF was associated with greater tensile strength when compared with PRP and control. However, more studies with a longer observation period and further trials, especially in humans, should be conducted to confirm this finding. Clinical Relevance: PRF injection can be a novel therapy consideration for ligament injury, with a better result in both function and histological appearance when compared with PRP.