Architecture of the periacetabular trabecular bone.

Abstract

The three-dimensional periacetabular bone architecture has been established by sectioning multiple pelves in coronal, parasagittal, and horizontal planes. Maximum compressive and tensile stresses were determined by a finite element model of the acetabulum. The architecture is symmetric in a given specimen, and quite similar from specimen to specimen. The subchondral bone is always much thicker than the trabecular bone, and greater stresses were predicted with the model in the subchondral bone (the magnitude of tensile stresses being greater than the magnitude of compressive stresses). There are two general systems of periacetabular trabeculae: the more prominent and regular is generally radial to the center of the acetabulum, and the less prominent, less regular is in more or less concentric spheres about the acetabulum. The direction of predicted compressive stresses corresponded to the radial system and the direction of the predicted tensile stresses corresponded to the concentric system; compressive stresses in trabecular bone were of higher magnitude than tensile stresses.