Preliminary results of uncemented metal on metal stemmed and resurfacing hip replacement arthroplasty.

Seventy uncemented stemmed total hip replacements and 35 uncemented surface replacements with all metal Metasul articulating surfaces were followed up in a prospective study. There was no evidence that this metal on metal articulation causes new problems or complications that were not known already from other polyethylene-aluminum oxide ceramic articulating combinations. The results of 64 of 70 patients could be assessed as excellent and good. When tissue samples obtained during 2 reoperations for ectopic ossification were examined histologically, there was no light microscopic evidence of metal particles. In these cases, aseptic loosening seemed to be due to the lack of initial fixation with the original femoral component design, and was not related to the use of the Metasul bearing. The metal on metal articulation reduces the production of particles considerably according to experience to date. It is therefore hoped that foreign body reactions due to wear particles will be significantly reduced. The results support the continued investigation of metal on metal joint replacements for younger, active patients.