Incongruent surfaces in the human hip joint

Abstract

Hammond and Charnley1 have recently given support to the view that the femoral head is almost exactly spherical, that the surfaces of the acetabulum and femoral head are congruent so that "very perfect contact of all parts of the cartilaginous surfaces is to be expected in any position of the hip joint". In the past, however, several observers2,3 were convinced that the surfaces of this joint are incongruent or, at best, fit one another in only one position. If the latter view is correct, contact will not be made over the entire joint and the site and size of the actual contact areas in a given joint will depend on the relative position of the joint surfaces and on the magnitude and direction of the load transmitted through it. © 1968 Nature Publishing Group.