Leveraging ultrasonic actuation during inclined orthopaedic bone drilling: An experimental and histological study

The treatment of fractured bones imperatively requires an orthopaedic bone drilling procedure. During the drilling of fracture bone, induced cutting force and temperature elevation may affect the initial stability and pullout strength at the bone-screw interface. Rotary ultrasonic-assisted drilling is gaining high attention to promote initial holding strength by reducing thermal energy and induced cutting force. Therefore, the proposed work is focused to leverage ultrasonic actuation to elevate the pullout strength by mitigating induced cutting force and temperature rise at the drill site. The technique of ultrasonicassisted drilling is compared with conventional drilling of porcine femur bones. The influence of different drilling parameters such as insertion angle, feedrate, rotational speed and ultrasonic amplitude was monitored on the output characteristics. The infrared thermal imaging technique and force dynamometer was used to monitor temperature elevations and induced force. An increase in induced cutting force was observed to surge thermal energy and microcracks that lead to temperature elevations. Moreover, higher temperature and cutting force resulting lower biomechanical pullout strength of orthopaedic bone screws. In order to evaluate the effects of heat generation on tissue damage, osteonecrosis and bone morphology, histopathological analysis was performed at the drilled sites. It was witnessed that ultrasonicassisted drilling was associated with higher viable lacunes and filled osteocytes leading to greater cell viability compared to conventional drilling. The present work shed light on an ultrasonic-assisted drilling system that is essential for low-trauma surgeries for orthopaedic applications. & COPY; 2023 Elsevier Ltd. All rights reserved.

Automated summary

This study aims to use ultrasound actuation to improve the pullout strength of orthopaedic bone screws by reducing induced cutting force and temperature rise during drilling. The results show that ultrasonic-assisted drilling leads to better cell viability and lower tissue damage compared to conventional drilling.