[Biomechanics of the hip joint. I. A new model for the calculation of the forces in the hip joint].
After a short review of the theory of the forces acting in the human hip joint we develope a new model for the calculation of the forces R acting on the head of the supporting femur, of their direction phi and of the maximal pressure of the femoral head. The new concept is the determination of a fixed point A, the attachement of the resultant muscle force M at the pelvis, and the insertion T of this muscle force at the trochanter. After determination of this points in a single standard radiography of the pelvis and hips, the model calculate the resultant force R at the hip joint. The pressure in the articulation is calculated also by the same proceeding. The influence of the choice of the point A is discussed.