[Evaluation of biomechanical models for therapy planning of total hip arthroplasty - direct comparison of computational results with in vivo measurements].

A consideration of the patient-specific biomechanical situation in the context of the surgical planning of total hip arthroplasty is highly recommended and may have a positive impact on the therapeutic outcome. In current clinical practice, surgical planning is based on the status of the individual hip and its radiographic appearance. Several authors proposed different biomechanical modeling approaches for the calculation of the resultant hip force R on the basis of parameters gathered from plain radiography. The comparative study presented in this paper shows that the biomechanical models by Pauwels, Debrunner, Blumentritt and Iglič provide a good approximation of the magnitude of R when compared to the in vivo data from instrumented prostheses. In contrast, the Blumentritt model resulted in abnormally high values. However, the computational results for the orientation of R show a high variability of all modeling approaches and seem to depend more on the model used than on patient-specific parameters. Georg Thieme Verlag KG Stuttgart · New York.