Fracture healing in the rat tibia: open medullary pin versus closed medullary pin insertion.

Fracture healing was compared in open medullary pin fixation and closed medullary pin fixation of the rat tibia to determine if the closed method promotes healing faster than the open method. Severe and mild closed tibial fractures were fixed immediately by open and closed medullary pin fixation methods, and fracture healing was tested mechanically. Diaphyseal fractures treated immediately by closed medullary pin fixation healed faster than those treated by the open pinning; the difference was statistically significant in mild fractures, but not in severe fractures.