The goal of this study was to examine the early retrievals of hydroxya
patite-(HA) coated hip prostheses to assess evidence of osteoconductiv
ity, resorption of HA, and the integrity of the HA/implant bond. Six r
etrieved HA-coated hip prostheses (3 femoral hip stems, 3 acetabular c
ups) were analyzed for the amount of bone ongrowth or ingrowth of the
HA-coated surface and the extent to which the coating was still presen
t after in vivo service. The examination of these six HA-coated prosth
eses indicates that HA appeared to be osteoconductive. There was evide
nce of debonding of HA from the smooth-surfaced femoral prosthesis, al
though that may have been a result of the extraction process. The five
plasma-spray surfaced, HA-coated prostheses showed evidence of consid
erable loss of the HA coating at the time of receipt in the authors' l
aboratory, although it is was not possible to determine the cause of t
he loss of coating.