PAST AND PRESENT IN HARD SURFACES TOTAL HIP REPLACEMENT

Abstract

The use of metal-on-metal THA has taken origin from the use of Mc Kee prostheses in our Institute in 1967. In 3rd Division of “Istituto Gaetano Pini” in Milan have been performed more than 1300 implants of these prostheses between 1967 and 1983. The analyses of implant surfaces after removal have demonstrated an almost null debris and good liability regarding implant stability. Even if someone assumed, in the past, the carcinogenic effects induced by metal debris, recent publications showed no statistically significant differences in the incidence of cancer between patients treated with metal-on-metal prostheses and normal population. The very good results in follow-up and the evidence of limited debris of metallic contact surfaces have encouraged us to continue with this experience using large head prostheses with metal-on-metal interface.

We implanted 73 Artek cup in 1997–2000 years, an uncemented pre-assembled cup, fixed by pure press fit. The advantages with this cup derived from his low profile (1/3rd of sphere) and contemporary use of large diameter heads (38 mm), similar to McKee’s model (35–41.5 mm). This design allowed us not only to preserve bone-stock, but even to reduce displacement risk. These advantages were increased by the absence of interposed PE surfaces, which inevitably suffer from time-related degeneration. In the last years we increase the use of hard surface THA, usually performing the implant of pressfit cups with metallic liner and large diameter heads (32 and 36 mm) or ceramic-ceramic interface. We believe in better indication (null-wear) of ceramic-ceramic THA in < 60 years patients (even in older ones high functional requests). Usually > 60 years we implant metal-on metal THA: we think that can guarantee very low debris rates and, if used in association with modular components and large diameter heads, a sensibly increased ROM and lower displacement rate.

We implanted 73 Artek cup in 1997–2000 years, an uncemented pre-assembled cup, fixed by pure pressfit. The advantages with this cup derived from his low profile (1/3rd of sphere) and contemporary use of large diameter heads (38 mm), similar to McKee’s model (35–41.5 mm). This design allowed us not only to preserve bone-stock, but even to reduce displacement risk. These advantages were increased by the absence of interposed PE surfaces, which inevitably suffer from time-related degeneration. In the last years we increase the use of hard surface THA, usually performing the implant of pressfit cups with metallic liner and large diameter heads (32 and 36 mm) or ceramic-ceramic interface. We believe in better indication (null-wear) of ceramic-ceramic THA in < 60 years patients (even in older ones high functional requests). Usually > 60 years we implant metal-on metal THA: we think that can guarantee very low debris rates and, if used in association with modular components and large diameter heads, a sensibly increased ROM and lower displacement rate.

The common use of hard surface THA has to be considered “gold standard” even in the elderly, in a constantly increasing mean-life era with corresponding better quality of life: we believe that is mandatory to offer, even to these patients, a long-lasting and high result hip arthroplasty.