Development of a New Device Implementing Standardized Closed Fracture in the Rat

The objective of the study was to produce a user-friendly device for creating standardized close fracture in an experimental animal. We describe a device that takes advantage of the elastic and plastic nature of the bone for producing a closed fracture with reproducible location and structure. Fractures were p roduced by a pendulum-like device applying an external blo w directly over the tibiae of female Wistar rats fixed to a platform by dynamic holders. The tibiae were immed iately stabilized by plaster fixation that was covered by dental wa x. Rad iographically, this method resulted in a highly reproducible bi -cortical transverse fracture. M inimal soft tissue damage was noticed around the fracture site. Creatine phosphokinase activity in the seru m and in the gastrocnemius muscle of the posterior calf compart ment was analy zed in order to evaluate the standardization of the soft tissue damage. The device is simp le to build and can be modulated and adapted to different sizes of animals. By using this device, a highly reproducible closed fracture system can be imp lemented with minimal damage to local soft tissues, but still with the local hematoma that is essential for the fracture healing process.