Results: The maximum principal stress focused on the cortical bone of sustentaculum tali in both the models under the same loading.
Conclusions: The placement of sustentaculum tali screw is essential for fixation of type II calcaneal fracture to achieve the biomechanical stability.
However as the powerful tendons and ligaments in the surrounding of the sustentaculum tali the displacement of the sustentaculum tali rarely occurs in the calcaneal fracture which might provide powerful fixation site for the screws to obtain stable fixation in biomechanics.
In this study we established the three- dimensional (3D) finite element model of Sanders type II calcaneal fracture and simulated two kinds of fixation methods namely AO calcaneal plate with an additional sustentaculum tali screw fixation or without sustentaculum tali screw fixation.
the internal fixation model with sustentaculum tali screw was 9.
The stress distribution in the calcaneus: After loading the maximum stress in the calcaneal model with sustentaculum tali screw was 78.
The stress distribution in the plate and screws: After loading the maximum stress in the implants with sustentaculum tali screw was284.
As for the analysis of the sustentaculum tali screw the minimum displacement of the sustentaculum tali screw was 0.
The biomechanical effect of the sustentaculum tali screw to the internal fixation of Sanders type IIcalcaneal fracture: In order to reflect the displacement and the stress distribution of the fracture line more veritably the fracture line was replaced and bonded by the soft material with the Modulus of elasticity 5 MPa and Poisson ratio 0.
It testified that the sustentaculum tali screw could provide additional stability to the Sanders type II calcaneal fracture.
In this study we also analyzed the sustentaculum tali screw alone and found the maximum displacement of the sustentac- ulum tali screw was 0.