Analysis of cutting forces and microdamage during indentation cutting of bone.

In surgery, bone can be cut by applying force to a wedge-shaped blade. The published literature is relatively sparse regarding the biomechanics of this type of indentation cutting, especially regarding the relationships between blade geometry, bone quality, cutting force and microdamage. Microdamage created near the cut surfaces can be beneficial, as a trigger for bone remodelling, but it is known that excessive fracture damage can prolong the healing time. In this research, specimens of compact bovine bone were tested by cutting using wedge blades of different geometries. We labelled and measured microdamage occurring during bone cutting for the first time. We found that there were statistically significant effects arising from the variation in wedge angle, edge radius and blade orientation (with respect to bone's anisotropic structure) on both the magnitude of the cutting force and the extent of the microdamage. Interestingly, we found that the amount of damage occurring during cutting is directly correlated to the cutting force which causes the damage, independent of other factors. This work contributes to a better understanding of the biomechanics of this important surgical cutting process.