A short representation of the scientific research:

Computational techniques for the simulation of stress adaptive bone remodelling have been developed and applied for the analysis of the bio mechanical compatibility of hip-joint endoprosthesis. These numerical simulations are in good agreement with clinical observations.

Hip joint endoprosthetics has been developed to standard surgery. However, there is a great variety of implant designs and surgery techniques and the question for an optimal solution is still not answered yet. Probably this question has to be answered individually from patient to patient. The 3D bone is given by [Viceconti 1996] and the muscle attachments can be found in [Viceconti 2003]. The first step of the computation treats the optimization of the boundary conditions (statically equivalent loads) in the sense that a bio mechanical equilibrium state is found for a physiologically density distribution in 3D, [Ebbbecke and Nackenhorst 2005]. The bone mass density distribution for an equilibrated femur model is depicted in fig. 1 and fig. 3. The comparison with CT--data and radiograph matches well. The hollow bone as well as the characteristic trabecular structure of the cancellous proximal femur is approximated well by the finite element model. The bone remodelling caused from the spiron prosthesis is shown in fig. 2. These investigations of prostheses are in close cooperations with the Medical Hight School of Hannover (MHH). The results from numerical simulations are in good agreement with clinical observations.

We are able to simulate the stress analysis of implants and the bone remodelling in 3d. Thus investigations of the densitiy distribution of the bone caused by implants make predicitions in the bone remodeling possible. Do not hesitate to ask.

Figure 1:

Computed mass density distribution (left) in comparison with a radiograph.

Figure 2:

radiograph in comparison with computed mass density distribution: Spiron Prosthesis, postoperativ left site, long therm effect right site.

Figure 3:

Computed mass density distribution (left) in comparison with a CT data set mapped onto finite elements.

Figure 4:

Bone remodelling for industries: orthotrop (left), isotrop (right).