Influence of the reamer shape on intraosseus pressure during closed intramedullary nailing of the unbroken femur: a preliminary report.

The generation of intramedullary pressure during reaming of the femur was compared for two different reamer systems: the AO/ASIF universal reamer and the Gray flexible reamer system (Howmedica), while reaming in 9 oncologic patients undergoing prophylactic nailing of metastatic femora as indicated by impending fractures (unbroken femora). An intracranial fibre optic catheter pressure-monitoring device inserted through the distal supracondylar cortex was used to perform measurements. Preliminary data are presented. Maximum pressures of up to 450 mmHg were recorded during reaming with the smaller 9.0 and 9.5 mm theta reamers. Rapid penetration of the reamer in both proximal and distal metaphyses caused much higher pressures than reaming the cortex of the diaphysis. Speed of penetration and volume of the reaming shaft were found to be important parameters. No significant differences between maximal pressures generated by the two types of reamers could be observed.