POSTMORTEM ANALYSIS OF CONSECUTIVELY RETRIEVED ASYMMETRIC POROUS-COATED TIBIAL COMPONENTS

The objective of this investigation was to conduct a postmortem analys is of 8 porous-coated asymmetric tibial components to measure the exte nt of radiolucencies and bone ingrowth. With the use of radiographic, electron microscope, and histologic analysis techniques, a quantitativ e postmortem study of 8 consecutively retrieved porous-coated tibial c omponents was conducted. Time in situ averaged 47 +/- 36 months. The c omponents were secured with 4 pegs and 2 screws. Autograft bone chips were applied to the resected tibia during implantation. Contact radiog raphs of an average of 8 3-mm sections from each implant revealed that 73% +/- 17% of the porous coating had no apparent radiolucencies pres ent between the host bone and porous coating for the series. Backscatt ered electron imaging showed that the bone ingrowth averaged 6% +/- 2% . Histologic analysis was unable to demonstrate any adverse cellular r esponse. The analysis suggested that this asymmetric implant design is stable and biocompatible and has potential for long-term clinical dur ability.