Anglia Ruskin University

To predict performances of different implant designs or fixation techniques, specialised medical and engineering software are used to extract information from medical images to create geometrically accurate three dimensional (3D) models of reconstructed bones and joints and to estimate bone material properties. 3D models of bones are constructed from CT scan data, using thresh-holding, region growing techniques and manual editing. A 3D volume mesh of the bone is created, using finite element module of Mimics and the material properties associated to Hounsfield unit of each voxel, is automatically assigned to each element of the mesh. 3D models of soft tissues are constructed from MRI data, using the 3D livewire technique. Image registration of the 3D models of the osseous tissues, from the CT-san data, and soft tissues, from the MRI data, is carried out, using the point and global registration techniques.

The registered 3D volume meshes for the bones and soft tissues are then exported to specialised finite element packages (ANSYS, COMSOL, LD-Dyna), where the boundary conditions, simulating physiological activities of daily living, are applied to the models. Finite element analyses are run on the different surgical fixation techniques or prosthesis designs to predict relative performances of different prosthetic designs and surgical fixation techniques. Verification of the finite element models will be carried out by parallel in vitro studies on cadaveric or animal models. The results will be used to further improve surgical procedures and implant designs.

Software Expertise:

• Mimics (Materialise, Belgium)
• ANSYS (ANSYS, Inc., USA)
• COMSOL (COMSOL, Inc. USA)
• LS-DYNA (Livermore Software Technology Corp., USA)
• CATIA (Applied PLM Ltd., UK)
• I-Deas
• COSMOS