Background: Collagen-based synthetic bone grafts which contain tricalcium phosphate (TCP) and hydroxyapatite (HA), and collagen-based synthetic bone grafts containing only TCP have some advantages compared to autografts. Therefore, these grafts are frequently used to fill bone defects and pseudoarthrosis.
Objectives: The aim of this study was to evaluate and compare the clinical, radiological and histopathological effects of TCP-HA and TCP alone + Type-1 collagen in healing lower extremity fractures in a pseudoarthrosis model in rat femurs.
Material and methods: A total of 36 female Wistar rats were randomly separated into 4 groups. Group 1 (n = 10) was the control group. A femur pseudoarthrosis model was created in Groups 2, 3 and 4. On the 90th day after the 1st surgery in Group 2 (n = 10), TCP-HA + Type-1 collagen was applied, in Group 3 (n = 10), TCP alone + type-1 collagen was applied, and in Group 4 (n = 6, the placebo group), saline solution was applied. Fixation was performed with an intramedullar pin. After 60 days and clinical and radiological scoring, all animals were sacrificed and a histopathological evaluation of the pseudoarthrosis areas was conducted.
Results: In all the clinical, radiological and histopathological measurements used in the evaluations of the differences between the groups, a higher rate of union was determined in Group 2 (TCP-HA). No significant difference was determined between Group 3 and Group 4 in terms of union rates.
Conclusions: The clinical, radiological and histopathological results of this study showed that TCP alone was less effective than TCP-HA in the union of a femur pseudoarthrosis model in rats. The reason for this difference was considered to be hydroxyapatite (HA).
Keywords: bone healing; collagen; pseudoarthrosis; rats; synthetic bone greft.