The evaluation of tension in an experimental model of external fixation of distal radius fractures.

A cadavaric model was used to evaluate the previously reported methods of determining excessive tension when applying an external fixator across the wrist. An osteotomy of the distal radius was performed and tension was applied incrementally across the joint in 9 cadaveric specimens. The fingers of each specimen could fully flex to the palm at all levels of tension tested. Although the radiocarpal and midcarpal joint spaces did lengthen with incremental changes in the amount of tension, there was no statistically significant correlation that could be made about the difference between the radiocarpal and midcarpal spaces and tension applied across the wrist. Although the carpal height ratio increased significantly from 0 to 10 lb of traction, the carpal height ratio appeared to plateau after further increases in tension. In conclusion, surgeons need to be careful when using any of these previously reported techniques for determining the optimal tension to be applied with an external fixator across the wrist. These techniques may not reproducibly allow the surgeon to detect whether there is excessive distraction across the distal radius fracture.