Outcome with a tapered, polished, anatomic stem

Abstract

Failure of a cemented total hip arthroplasty (THA) is a rare event even in the long term. With improved cementing techniques, excellent and consistent long-term outcome has been achieved with a number of different femoral stem designs [1, 11, 21, 25, 32, 36, 37, 42]. However, some implants seem to perform better than others [32] and some very different design and anchorage philosophies [24, 40] can be identified (Chapter 7.1) A modern stem design should be easy and reproducible to implant for any surgeon including the trainee, but should also forgive minor mistakes and provide long-term survival of at least 95% after 10 years [33]. For long-term survival a complete cement mantle of adequate thickness [19, 28, 29] is of significant importance. There is no doubt that a thin or deficient cement mantle can lead to cracks, which create a pathway for wear particles to induce osteolysis and loosening [24, 26, 31]. Hence, it is considered important to create not only a sound cement interlock, but also an optimal cement mantle around the femoral stem at operation. It is the surgeon who manufactures the cement mantle, which also depends on a variety of factors (chapter 5.2). including femoral anatomy, bone preparation, stem design and size and centralizer usage [10]. Most stem designs are straight and an obvious dilemma exists, if one considers the femoral anatomy in the lateral plane, which is curved [15]. Accordingly, a typical sagittal mal-alignment pattern of straight stems has been identified both clinically and experimentally [10, 15, 35] on lateral radiographs. This inevitably leads to areas at risk for producing thin cement mantles [10]. To address this anatomical fact and to minimise the risk of a deficient cement mantle, the Olympia hip stem, an anatomical, tapered and highly-polished design, has been developed and used clinically since 1996. This chapter describes the 9-year survival and radiographic outcome of the Olympia stem in the first 120 consecutive cases implanted between 1996 and 1998. © 2005 Springer Medizin Verlag Heidelberg.