THE RESULTS WITH 2 TYPES OF UNCEMENTED AC ETABULAR CUPS IN TOTAL HIP REPLACEMENTS

We have followed up 227 total hip replacements using a cementless mini madreporic prosthesis for an average of 9 1/2 years. Special attention was paid to the acetabular component, of which 2 types were used; 77 incorporated screw rings and 134 were stabilised by spikes. The screw prostheses were evaluated at an average of 8 1/2 years from operation; one third showed radiological evidence of migration, and revision bec ause of this was required in 12.6% of cases. The spiked cups were foll owed up for an average of 10 years; 14.8% showed radiological evidence of migration and 2.3% needed revision. We observed no radiological fe atures to explain this difference. The quality of the bone and the mec hanical characteristics of the bone/implant contrast may influence the result. We feel that an uncemented spiked acetabular implants is a wo rthwhile concept.