Bone Cutting Efficiency and Heat Generation Using a Traditional Fluted Burr and a Novel Fluteless Resurfacing Tool

Abstract

Category: Basic Sciences/Biologics; Other Introduction/Purpose: Meticulous bone removal is a critical step in many orthopaedic foot and ankle procedures including arthrodesis, decortication, and hardware removal. Power tools, including burrs, allow for increased efficiency and potentially more uniform bone removal; however, due to friction generated, there is a known risk of thermal-induced osteonecrosis. A fluteless resurfacing tool (RT) has been manufactured in hopes of optimizing cutting properties by increasing cutting efficiency and decreasing bone-burr contact heat generation. The purpose of this cadaveric study was to compare the cutting rate and heat generated using a traditional fluted burr (FB) and a fluteless RT on human cadaveric bone (Figure 1). We hypothesized that during bone removal, the fluteless RT would provide faster cutting rates than a traditional burr. Methods: Twenty cadaveric metatarsals were tested with four predetermined cutting forces to evaluate heat generation and cutting rate for the fluted burr and fluteless resurfacing tool over 40 seconds or until a depth of 4 mm was reached. Cutting rate was calculated from displacement transducer data. Heat generation was measured by thermocouples placed in the bone adjacent to the burring site. Assuming a body temperature of 37°C, a 10°C increase in heat was used as the threshold of inducing osteonecrosis. Results: At 1.0 N and 1.7 N, the thermal osteonecrosis threshold was reached at comparable times between burrs, while the bone removed by the resurfacing tool was on average five times greater than fluted burr at 1.0 N and over twice as great at 1.7 N. Statistical analysis of these common cutting forces showed the resurfacing tool had significantly higher cutting rates (P < 0.01). As a result, the fluted burr produced higher temperatures for the same amount of bone removal (P < 0.01). Conclusion: In a cadaveric study, the fluteless resurfacing tool demonstrated higher bone cutting rates and lower heat generation for the same amount of bone removed than a traditional fluted burr.