Performance evaluation of a cement-augmented intramedullary fixation system for pathologic lesions of the femoral shaft.

To improve intramedullary fixation with polymethylmethacrylate for use in pathologic bone, a new fixation system was developed. A fluted intramedullary rod was modified to allow injection of low-viscosity polymethylmethacrylate (PMMA) through the rod with retrograde filling of the void spaces between the rod and the medullary canal. This provided uniform distribution of the cement along the length of the rod and significantly improved fixation stability. Biomechanical testing using this system on simulated pathologic lesions of the femur showed a twofold increase in torsional strength over intramedullary methods previously used, with strength approaching that of the intact femur. In 16 patients, the device made mobilization possible immediately after the operation.