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

Abstract

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.

Minimally invasive surgery with locking plate for periprosthetic femoral fractures: technical note

“…Periprosthetic screws must sometimes be inserted in cement, especially when proximal and surrounding a HA. It has been proven that cement is not affected by these screws [28,29] as the heat produced by drilling is harmless [30]. In presence of an intramedullary implant, one must bridge it to avoid stress fracture on a weak spot [31] and must be bridged by the length of two diaphyseal diameters [11].…”

Concepts and Potential Future Developments for Treatment of Periprosthetic Proximal Femoral Fractures

“…Using a custom-made internal cooling device within the power drill setup reduced temperatures during drilling to tissue-preserving levels for cemented hip stems (24.7 °C) [ 45 ]. However, the same research group also demonstrated that for cementless hip stems without the insulating cement layer, the temperature during drilling increased to 47 °C, even when the internal cooling device was applied [ 46 ]. These studies indicate a potential solution for the concern of tissue-preservation during transprosthetic drilling, with however some further research being required especially for cementless hip stems.…”

Impact of intraprosthetic drilling on the strength of the femoral stem in periprosthetic fractures: A finite element investigation

“…Concerns about high drilling temperatures potentially causing osteonecrosis could be sorted out. 29,30 However, the impact of drilling the hip stem on implant integrity has not been investigated yet. Drill holes may weaken the strength of the prosthesis, potentially leading to material failure and breaking of the prosthesis.…”