Using finite element analysis we have studied the pelvic bony socket and co
mpared it with radiological imaging using threaded acetabular cups of three
different shapes (parabolic, conical, hemispherical). The two-dimensional
model depicted a planar section through a left pelvic hemisphere. In all th
ree cups the stress in the bony socket increased from lateral towards media
l. Compressive stress was found on the superior and inferior parts of the c
up, but mainly on the superior aspect, seen radiologically as new trabecula
r bone formation. The maximum compressive stresses were seen in the cranial
curvature of the conical cup, with less in the parabolic form and least in
the hemispheric form. The tensile stress at the bottom of the socket incre
ased from the hemispheric to the conical shape. Radiological rarefaction ga
ve an indication of lower stress. There was lower compressive stress betwee
n the teeth of the threads. This FE model uses computer simulation to predi
ct bony changes with different designs of implant. The ability to simulate
biological conditions is a valuable addition to the testing of mechanical s
trength.