CORROSION AND WEAR AT THE MODULAR INTERFACE OF UNCEMENTED FEMORAL STEMS

We examined 108 uncemented femoral stems with modular femoral heads wh ich had been retrieved for reasons other than loosening. There were de tectable amounts of wear and corrosion in 10 of 29 (34.5%) mixed-alloy components and 7 of 79 (9%) single-alloy components after a mean impl antation time of 25 months. We found no correlation between the presen ce or extent of corrosion or surface damage and any of time in situ, i nitial diagnosis, reason for removal, age, or weight. Stems with wear and corrosion were less likely to show histological bony ingrowth. The interface between the head and stem of modular total hip components i s a possible source of ion release and wear debris, but wear and corro sion were totally absent in most specimens. This suggests that this pr oblem could be avoided, and that further research is required to devel op manufacturing methods which would minimise such changes.