The effects of filling experimental large cortical defects with methylmethacrylate.

Three studies were performed using paired cadaver femurs to determine the effectiveness of filling large lytic defects of the femur with methylmethacrylate. In the first test, the paired femurs were prepared with a 2.5 cm defect in the femoral cortex. One of the paired femur defects was then filled with methylmethacrylate, while the other femur was left unfilled. The femurs were then tested in axial loading until failure. In the second test the paired femurs were prepared in the same manner and tested in torque until failure. In the third test, one of the paired femurs was prepared with a 2.5 cm defect and filled with methylmethacrylate while the other femur was left intact. When comparing those femurs whose defect was filled with methylmethacrylate to the prepared femurs that remained untreated, a significant increase in axial load strength of approximately 50% and an increase in torque strength of approximately 70% was found. It would seem that filling large lytic defects with methylmethacrylate at the time of internal fixation would significantly increase strength in both axial and torsional loadings.