2021/12/16 | Research | Biomechanics

Predicting screw fixation strength for fractured bones

In collaboration with the AO Research Institute Davos, the Musculoskeletal Biomechanics group has assessed three different strategies to determine the stability of screws used to fix bone fractures. In an experiment with human cortical bone specimens the team could show that explicit, nonlinear micro-finite element simulations captured fixation strength most accurately.

Screws used to stabilize fractures in orthopedic surgery are often the weak point in a bone fixation system and determine implant failure. For this reason, a group of researchers from the AO Research Institute Davos and the ARTORG Center have looked into ways of better predicting the pull-out force of 3.5 mm screws in human tibial cortical bone. Three strategies were compared: micro-computer tomography image-based bone volume measure, implicit linear micro-finite element (FE) simulation and explicit nonlinear micro-FE simulation.

The study yielded a more accurate and quantitatively correct result with explicit nonlinear micro-FE. Hence, this technique will be further explored to optimize implant design, towards improving surgical outcomes and ultimately reducing failure rates.