DEVELOPMENT OF IN-SITU TEMPERATURE PREDICTION MODELS FROM CADAVERIC HUMAN FEMUR FOR BONE DRILLING

Abstract

Thermal osteonecrosis of bone in drilling procedure is caused by improper parameters which can lead to poor bone-implant integration and loss of fixation. In this study, Taguchi technique for parameter optimization and multiple regression models for temperature prediction were employed. The main aim of the study was to determine the optimal parameters of bone drilling to control the temperature rise below the thermal osteonecrosis threshold (47[Formula: see text]C) in respect of the bone density variations at different drilling directions. A 32 full factorial design with nine sets of parameters was used in the study. Drilling operations were performed along the longitudinal, radial and circumferential directions at the proximal-diaphysis, mid-diaphysis and distal-diaphysis regions of the 10 adult cadaveric femurs with different feed rates (40, 60 and 80[Formula: see text]mm/min) and spindle speeds (500, 1000 and 1500[Formula: see text]rpm) using 3.2[Formula: see text]mm diameter surgical drill bit. The in-situ drilling temperatures were measured with T-type thermocouple. The optimum drilling parameters for each drilling direction were determined from signal to noise ratios and the effect of each parameter was determined using analysis of variance. By using computed tomography scan data of patients, the proposed method is able to predict the temperature rise at the bone-drilling sites, optimal parameters and possibility for the occurrence of thermal osteonecrosis. This important tool could assist in reducing localized temperature induced from surgical drilling by up to 32% and 18[Formula: see text]C and as such significantly reduce associated osteonecrosis and improve patient outcome and quality of life.