A torque/applied force tool for orthopaedic surgeons
11 February 2013
Researchers have developed a novel surgical instrument handle that indicates when the correct torque or force has been applied when using screwdrivers or spreaders.

Once the optimal torsional moment is reached, an LED on the inside of the instrument handle lights up (image: Fraunhofer IPA)
Researchers at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart have developed a vulcanized instrument handle, into which surgical tools – such as screwdrivers or spreaders – can be screwed. The handle, developed in collaboration with Weber Instrumente GmbH, contains sensor that are able to measure applied torque and force.
By integrating electronic components into the handle, surgeons are given feedback during a procedure, advising them if they can insert the instrument even further. For example, if a screw is tightened, the sensors measure the applied force. Once the optimal torsional moment is reached, LEDs signal this to the surgeon. The LED light can be seen through the transparent silicone sections of the handle.
The necessary power to the instrument is supplied by an internal battery, which is charged inductively.
All of the electronics – including the sensors and LED – are contained within the handle, rendering the assembly aseptic. The instrument handle can be sterilised at 134 degrees Celsius, without harming the internal electronics, which are switched off during the sterilisation process.
The researchers intend to equip the handle with a wireless interface, so that the sensor data can be transmitted to a PC, thus allowing the surgical process to be documented.
A prototype will be on display at the Fraunhofer joint exhibition booth (Hall 3, Booth B04) at this year’s Medtec trade show in Stuttgart from 26 to 28 February.