Introduction: Osteonecrosis may be triggered by bone temperatures above 47o C during routine orthopaedic bone cuts using power-driven saws with potentially negative impacts on bone healing. A new oscillating-tip saw blade design (PrecisionVR; Stryker, Kalamazoo, USA) has been recently developed with a saw blade design that may influence the amount of heat generated. We have, therefore, sought to compare the bone temperature achieved using this new blade design with a standard oscillating saw during a standardized cutting task. Method: Six human cadaveric femora were obtained. Each femur was clamped and a distal femoral cutting jig was applied. An initial cut was performed to visualize the distal metaphyseal bone. The cutting block was then moved 2mm proximal and a further cut performed, measuring the temperature of the bone with an infrared camera. This was repeated, moving the block 2mm proximal with each cut, alternating between a standard oscillating saw blade (12 cuts) and the PrecisionVR saw blade (12 cuts). The bone density at the level of each slice was established from a CT scan of each specimen which had been performed prior to the experiment. Results: The two blades did not differ with respect to the integrated mean temperature calculated for each cut (p=0.89). The average peak temperatures were not significantly different between blades (p=0.14). There was no significant difference between blades for peak heating rate (p=0.7), although the area of bone heated above the 47 deg osteonecrotic threshold was significantly (p=0.04) less for the standard saw blade. Conclusions: The PrecisionVR blade may have advantages over standard oscillating blade, but reduced heat generation was not observed in this study. Indeed, the PrecisionVR blade generated heat that exceeded the bony osteonecrosis threshold in a greater proportion of bone than the standard blade, questioning its use for osteotomy or uncemented knee arthroplasty. Further work should examine modifications to the blade design to better optimize the requirements of speed, accuracy and heat generation.
|Number of pages||4|
|Journal||Journal of Medical Devices, Transactions of the ASME|
|Publication status||Published - 24 Jun 2013|