Testing and research of drilling feed force on fresh porcine femur / 医用生物力学

ABSTRACT

Objective To record the drilling feed force on different layers of fresh porcine femur, so as to provide reference for collecting and outputting the feedback signals of drilling feed force for orthopedic virtual surgery system. Methods The biological bone drilling feed force testing system was established by modifying the universal material testing machine and adjustable speed electric drill (drill bit Φ5.0 mm). The feed forces on 6 fresh porcine femoral shafts with a total of 162 drilling markers were collected at 3 different rotate speeds (n＝500, 800, 1 200 r/min) and 3 feed speeds (v＝30, 50, 70 mm/min), and their variation with corresponding tissues and locations were also analyzed. Results At the same drill marker of the fresh porcine femur, the drilling feed force on bilateral cortical bone was the largest (fmax＝103.63~142.59 N), while that on marrow cavity was the smallest, which was almost close to zero, and the drilling feed force on the middle part (f4,5,6＝124.69 N) was larger than that at two ends (f1,2,3,7,8,9＝121.84 N); the drilling feed force was smallest (f＝106.04 N) at v＝30 mm/min, n＝1 200 r/min, while the largest drilling feed force (fmax＝139.84 N) appeared at v＝70 mm/min、n＝500 r/min. Conclusions The modified drilling feed force testing system could efficiently collect the biological bone drilling data. The drilling feed force had a close relationship with bone structure, feed speed and rotate speed of electric drill as well. A larger bone density, smaller rotate speed of electric drill and higher feeding speed would lead to a larger drilling feed force, and vice versa. The accurate drilling feed force data and its variation tendency on porcine femoral obtained in this experiment could provide a reliable basis for force-feedback signal output in the virtual orthopedic surgery system.