Effect of Operating Parameters on the Removal of Bone Cement by a Sawing Process

Currently, there are approximately 33,000 total knee arthroplasty revision surgeries each year. This number is expected to increase with the aging population. During revision surgeries, metal implants are often secured to the tibial plateau by creating a mantel of polymethylmethacrylate (bone cement) that must be removed during revision, often times by sagittal sawing. Presently, there are no published studies on the mechanics of bone cement removal by a sawing process. The aim of this research was to quantify the effect of blade speed and applied thrust force on the volumetric cutting rate of bone cement. A custom reciprocating saw with variable stroke length was used to conduct a three factor Design of Experiments. Two levels, without center-points, were sufficient to model the effect of stroke length, thrust force, and reciprocating speed on cutting rate. The results demonstrate a linear relationship between both force and cutting rate, and blade speed and cutting rate. A cutting rate model was developed by regression analysis of the experimental data. The model has applications in haptic feedback for surgical simulators. This study provides a basis for understanding the operational parameters of the bone saw, which is the first step in designing saw blades for cutting bone cement as these designs may differ significantly from those optimized to cut cortical bone.