Mo. Heller et al., Influence of femoral anteversion on proximal femoral loading: measurement and simulation in four patients, CLIN BIOMEC, 16(8), 2001, pp. 644-649
Objective. The aim of this study was to determine the loading of the proxim
al femur during daily activities and to quantify the influence of femoral a
nteversion.
Design. This study combined experimental and analytical approaches to deter
mine the in vivo loading at the hip joint. A numerical musculo-skeletal mod
el was validated against measured in vivo hip contact forces and then used
to analyse the influence of anteversion on the loading conditions in the fe
mur.
Background. Musculo-skeletal loading of long bones is essential for joint r
eplacement and fracture healing. Although joint contact forces have previou
sly been measured in selected patients, the interaction between femoral ant
eversion and the associated musculo-skeletal loading environment remains un
known.
Methods. The gait of four patients with force measuring hip prostheses was
analysed during walking and stair-climbing. Musculo-skeletal loading was de
termined using individual numerical models by minimising the sum of the mus
cle forces.
Results. Experimentally and numerically determined hip contact forces agree
d both qualitatively and quantitatively. Muscle activity resulted in compre
ssion of the femur and small shear forces in the meta- and epi-physeal regi
ons. Increasing the anteversion to an angle of 30 degrees increased hip con
tact forces and bending moments up to 28%.
Conclusions. This study has shown that femoral anteversion has a strong inf
luence on the musculo-skeletal loading environment in the proximal femur.