Effect of Sagittal Sawing Parameters on Histopathology of Bone

A sagittal saw is used for resection of bone during joint replacement surgery. During sawing, tissue at the cut surface can be damaged by high temperatures, which may lead to aseptic loosening of implants. To date, there have been no studies relating sagittal sawing parameters to the level of tissue necrosis. The aim of this study was to determine the feasibility of using histopathological analysis in assessing the severity of thermal necrosis due to sawing. All sawing experiments were performed on cortical bone taken from fresh bovine femur. A two factor, two level design of experiments was performed looking at applied thrust force from 15 N to 30 N and blade oscillation speed from 12,000 cpm to 18,000 cpm. Each cut was subjected to standard histological preparation and the depth of empty lacunae was measured. Both experimental factors, force and speed, showed a statistically significant effect on the depth of thermal necrosis (p< 0.05). However, the interaction of speed and force did not prove to be statistically significant (p = 0.22). From a clinical perspective, the results indicate that choosing higher blade speeds and applying greater force can reduce the amount of thermal damage during sagittal sawing.