A femoral model with all relevant muscles and hip capsule ligaments

Abstract

In order to evaluate stabilisation systems in trochanteric femoral fractures with finite element (FE) analysis, a realistic model is required. For this purpose, a new model of a femur with all the relevant muscles and the hip capsule ligaments is set up. The pelvic and tibial bones are modelled as rigid bodies so as to take all the muscles attached to the femur into account. Fracture zones in the proximal femur are defined. Following the modelling of the geometry, the isotropic material behaviour and the load application, a numerical calculation of the femur is carried out. The static iterated FE simulation shows good agreement with in vivo data for the one-leg-stance phase during walking and Pauwels' one-leg stance regarding the displacement of the femoral head (2.9 and 5.2 mm, respectively) and the resulting hip force (253% and 294% bodyweight, respectively). In the modelled fracture zones without osteosynthesis, shear is higher than axial strain. The reduction of shear among others could be a criterion for judging the quality of a stabilisation implant.

Keywords::

• trochanteric fracture
• femoral model
• musculature
• finite element analysis