Investigation of the Effects of Platelet Rich Plasma (PRP) on Fracture Healing in Rabbits

Fracture healing can be divided into two groups; primary (direct) healing with internal remodeling and secondary (indirect) healing with callus. Fracture healing consists of three biological phases; Inflammation, Repair and Remodeling. Having many factors that have negative effect on fracture healing yield us to find the factors that have positive effects. Platelets are the small blood cells that include growth factors and cytokines, which are involved in the healing of the tissues that are rich with alpha and dense granules. PRP contains platelet concentration of approximately 3 to 5 times more than normal blood platelets (thrombocytes). PRP affects the inflammation, repair and remodeling phases of healing of the bone tissue. In recent years, studies have been conducted on the impact of Platelet-rich plasma (PRP) on fracture healing. This study investigates the effects of the PRP on the fractures in rabbits with comparison to the control group. Prepared samples were evaluated in terms of cortical callus formation, the percentage of chondroid, woven bone area percentage, vascular proliferation, osteoblastic activity, fibroblast proliferation and lamellar bone formation, in order. Staging technique of Curtis et. al. is evaluated with modification. Cortical callus formation in group-A rabbits is found significantly lower compared to the group-B rabbits. The percentage of chondroid tissues in group-A rabbits is found similar as in group-B rabbits. The woven bone area percentage of group-A rabbits is observed higher than the ones in group-B rabbits. Vascular proliferation is observed higher in group-B rabbits than in group-A rabbits. Osteoblastic activity is found at similar levels in both group-A and group-B rabbits. Fibroblast rich areas are observed more easily and fibroblast proliferation is significantly higher in group-A rabbits than in group-B rabbits. Mature bone formation is observed in all group-B rabbits while most of the group-A rabbits do not indicate any mature bone formation. Only two of radiographies belong to group-A rabbits present union while the rest of group-A radiographies show weak union indications. In all group-B rabbits, significant union is present at various levels. Mann-Whitney U test is applied. In terms of the cortical callus induction, the percentage of woven bone area, and fibroblast proliferation; the median difference between the two v groups is found as statistically meaningful (P <0.01). The median difference between the two groups in terms of chondroid percentage and osteoblast proliferation is not significant (P = 0.154, P = 0.336). By T test for vascular proliferation, the difference between the two groups is statistically significant average (P <0.01). Although there is not enough number of subjects needed to achieve significant results with Ratio test, the difference between the two groups in terms of lamellar bone formation is statistically significant (P <0.01). The data obtained with respect to radiological union criteria is found statistically significant in terms of union percentages (P <0.05). In recent years, with the increase in factors that affect fracture healing, delayed union or non-union occurs often. This study shows that PRP applied to the fracture line accelerates the fracture healing process as well as it increases the chance of union