M. Kothari et al., SURFACE GEOMETRY OF RETRIEVED MCKEE-FARRAR TOTAL HIP REPLACEMENTS, Clinical orthopaedics and related research, (329), 1996, pp. 141-147
A coordinate measurement machine was used to determine the surface geo
metry of 22 retrieved McKee-Farrar total hip replacements. The radial
clearance of each acetabular cup-femoral head pair was computed to see
whether there was potential for hydrodynamic lubrication. The surface
geometry was used to estimate the volumetric wear for the acetabular
cup and the femoral head, and to assess whether those prostheses that
had the potential for fluid film lubrication also displayed lower wear
. The volumetric wear rate for each prosthesis was estimated by dividi
ng the volumetric wear by the corresponding service life. Two distinct
wear patterns were seen on the femoral head. Prostheses displaying po
lar wear on the femoral head showed significantly greater service live
s than those displaying nonpolar wear. Although several prostheses had
clearances that provided for the possibility of hydrodynamic lubricat
ion, no correlation could be found between clearance and the measured
wear.