Forces generated in guide-wires when drilling human bone

Area of Science:

• Orthopaedic Surgery
• Biomechanical Engineering
• Materials Science

Background:

• Guide-wires are crucial in orthopaedic surgery for creating pilot holes in bone during fracture repair.
• Standard guide-wires (1.5-2.5 mm diameter) feature three-faceted points, with or without screw threads.
• Research into bone drilling mechanics is essential for improving surgical techniques.

Purpose of the Study:

• To evaluate the drilling performance of standard guide-wires against a novel two-faceted geometry.
• To analyze the influence of guide-wire design and drilling parameters on torque and thrust forces.
• To determine optimal drilling parameters for human bone.

Main Methods:

• Drilling tests were conducted on human femur heads obtained from hip arthroplasty.
• A variable speed drilling machine and a sensitive drilling dynamometer were employed.
• Torque and thrust forces were measured during experimental drilling with different guide-wire types.

Main Results:

• Threaded-point guide-wires offered minimal advantage and could be disadvantageous compared to non-threaded types.
• Thrust cutting force was significantly dependent on spindle speed and feed rate.
• An optimal spindle speed range of 800-1400 r/min was recommended for 2.5 mm guide-wires.

Conclusions:

• Guide-wire design, particularly the point geometry, impacts drilling efficiency in orthopaedic surgery.
• Optimizing spindle speed and feed is critical for managing cutting forces during bone drilling.
• The findings provide valuable data for the development of improved surgical guide-wires and techniques.