TOTAL HIP REPLACEMENT IN YOUNG PATIENTS

The increasing number of total hip replacements in young patients in recent years, is accompanied by an increased number of revision operations due to excessive wear of the polyethylene in the young active patient, leading to osteolysis and loosening of the prosthesis. For this reason, there has been extensive research to find alternative bearings with better wear properties to cope with this tremendous devastating problem. At this moment, ceramic-on-ceramic and metal-on-metal seem to be the most suited alternatives for the metal-on-polyethylene bearing in the young active patient.

Ceramic-on-ceramic prostheses

New in our clinic is the use of DELTA ceramic-on-ceramic prostheses (figure 4 and 5). The Ceramtec Biolox®delta is a prosthesis which has a new ceramic mixture. Due to the adding of zirconium and chromiumoxide (pink colour), the couple is now even better than the previous ones (Biolox®Forte).

Metal-on-metal prosthesis (figure 1 and 2)

Today there is a new type of metal-on-metal prosthesis used in the ANCA medical centre. (www.wmt.com en www.hipreplacement.com) These are fabricated from a harder cobalt-chromium alloy, and thus consist of a metal-on-metal couple. This new combination creates a differential hardness between the two moving parts. This differential makes that the metal is likely to release less particles into the body and wear less over time. (figure 3 and 4) In all hip prostheses the femoral head wears quicker than the acetabular shell (except the metal-on-polythylene ones (hard-on-soft)). The difference in hardness is a major advantage over the previous metal-on-metal prostheses and even more over the metal-on-polyethylene prostheses.

Metal Bearings: Hip Resurfacing

The Birmingham Hip Resurfacing (BHR), designed by Derrek McMinn, and Conserve Plus (C+) are used in our clinic. These prostheses are conform with the mentioned philosophy concerning young patients.