Development of a Finite Elemente Tool to evaluate/validate the stability of osteosynthetic treatments

Status:

completed 06/2009

Aims:

The goal of this research project was to create a tool that helps surgeons predicting the most stable treatment option for fractures. This Finete Element (FE) tool offers an opportunity to assess mechanical stability for preoperative planning. The calculations are based on CT-Scans (CT: computed tomography) of the fracture region. A computer algorithm was developed which automatically incorporates CT-data into the Finite Element Program. This combines the information of the patient´s scan with previously saved data of the osteosynthetic material (i.e. nail or plate).

Activities/Methods:

From the combination of the individual´s CT information of the fracture and the saved data of the osteosynthetic materials, the mechanical stability of the fracture treatment is directly estimated. To develop this computer algorithm not only the Finite Element Method was needed but also the validation through biomechanical testing. The validation was performed on cadavers to be as realistic as possible. They were fractured and stabilized as preoperatively planned. The mechanical testing was performed according to normal physiologic loads.

Results:

Within the project a reliable and validated process to apply CT-data for the simulation with the Finite Element Method could be developed. The extensive studies for the simulation of the correlation of bone and implant as well as single fracture fragments delivers good results and line the base for the final validation of the "Finite Element Stability Tool" (FEST). FEST is about to be fully operable. However, at the moment the application of FEST is still reduced to human femur. Only for this bone the whole process concerning reliability and contact to reality could sufficiently be determined. A user friendly interface for physicians could not be developed so far, therefore the application of FEST is momentarily reserved for specialists in numeric simulations and processing medical image data. The clinical application of FEST is only conceivable for elective procedures. E.g. studies of pseudarthrosis or other delayed cure are possible to identify the best biomechanical implant for revision.

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