Cortical bone drilling and thermal osteonecrosis.

Abstract

Bone drilling is a common step in operative fracture treatment and reconstructive surgery. During drilling elevated bone temperature is generated. Temperatures above 47°C cause thermal osteonecrosis which contributes to screw loosening and subsequently implant failures and refractures. The current literature on bone drilling and thermal osteonecrosis is reviewed. The methodologies involved in the experimental and clinical studies are described and compared. Areas which require further investigation are highlighted and the potential use of more precise experimental setup and future technologies are addressed. Important drill and drilling parameters that could cause increase in bone temperature and hence thermal osteonecrosis are reviewed and discussed: drilling speed, drill feed rate, cooling, drill diameter, drill point angle, drill material and wearing, drilling depth, pre-drilling, drill geometry and bone cortical thickness. Experimental methods of temperature measurement during bone drilling are defined and thermal osteonecrosis is discussed with its pathophysiology, significance in bone surgery and methods for its minimization.