Histological assessment of fracture healing after reduction of the rat femur using two different osteosynthesis methods.

Osteosynthesis using Kirschner (K) wires and plates with screws were compared on the same subject in a previous experimental protocol, but none of them led to fracture healing. We designed a new murine study in order to compare this two methods on different subjects in order to obtain histological proofs of which one is better and to see how limited periosteum removal influence fracture healing. Divided in two equal groups, femoral osteotomies were performed on 30 Brown Norway rats, then reduced using plates and screws in the OPS (osteosynthesis using plates and screws) group and using K-wires in the OIKW (osteosynthesis using Kirschner wire) group. The animals underwent clinical, radiological and histological assessment for eight weeks. The quality of the fracture healing was associated with a higher number of osteocytes/microscopic field at eight weeks. The difference between the groups regarding the number of osteocytes inside lacuna was statistically significant (t-test for equal variances not assumed, p=0.001), which confirms a mean difference of 32 cells÷microscopic field (mf) with a 95% confidence interval of 15-50 cells÷mf. In conclusion, limited periosteum removal did not influence negatively fracture healing. Therefore, we considered that osteosynthesis using plates and screws led to better results compared to fracture fixation using K-wires.