Different thermal conductivity in drilling of cemented compared with cementless hip prostheses in the treatment of periprosthetic fractures of the proximal femur: an experimental biomechanical analysis.

PURPOSE: The purpose of this study was to evaluate the different temperature levels whilst drilling cemented and cementless hip prostheses implanted in bovine femora, and to evaluate the insulating function of the cement layer.
METHODS: Standard hip prostheses were implanted in bovine donor diaphyses, with or without a cement layer. Drilling was then performed using high-performance-cutting drills with a reinforced core, a drilling diameter of 5.5 mm and cooling channels through the tip of the drill for constantly applied internal cooling solution. An open type cooling model was used in this setup. Temperature was continuously measured by seven thermocouples placed around the borehole. Thermographic scans were also performed during drilling.
RESULTS: At the cemented implant surface, the temperature never surpassed 24.7 °C when constantly applied internal cooling was used. Without the insulating cement layer (i.e. during drilling of the cementless bone-prosthesis construct), the temperature increased to 47 °C.
CONCLUSION: Constantly applied internal cooling can avoid structural bone and soft tissue damage during drilling procedures. With a cement layer, the temperatures only increased to non-damaging levels. The results could be useful in the treatment of periprosthetic fractures with intraprosthetic implant fixation.