Identification of geometrical parameters of femoral heads for hip joint mechanical model

摘要

The femoral head is a protrusion that fits together with the acetabulum of the pelvis. This joint called hip joint is an important joint in the body. It transmits the body weight to the lower limb and allows humans to move. In most textbooks, there is an excellent congruence between the articular surfaces, thus describing the femoral head and the acetabulum as perfect spheres. Some studies (Hammond and Charnley 1967; Blowers et al. 1972) confirm that the shape of the femoral head is a sphere. However, Cathcart (1972), Oonishi et al. (1976) and Menschik (1997) describe shapes that deviate from the pure spherical. The results of these studies are not consistent and sparse. Works on the geometric shapes of osteoarthritis heads are even rarer. Understanding the shape of the femoral head would allow to better understand the onset of certain diseases like osteoarthritis or efficiently analyse the pressure distribution in the joint and to improve resurfacing prosthesis. The objective of this study was to identify the shape and geometrical parameters associated with arthrosic and non-pathological femoral heads via the use of a 3D scanning (digitisation) and of an identification by an inverse method.