Abstract
Historically we know that all femoral, cemented stems have not performed the same. The Muller stem with its sharp comers did not perform as well as the Charnley femoral component. Titanium femoral components have not performed as well in the cemented situation as have stiffer chrome cobalt components.
Today we have come to recognise that the durability of a cemented femoral component is dependent on a number of variables to include stem geometry and surface finish as well as the cement technique.
Since several designs including the Trapezoidal-28, the Exeter, and the Iowa have incorporated various surface finishes over time, the issue of surface finish is one that some investigators think is relatively important. Components with rougher surface finishes adhere better to cement, decrease cement strains, and when they become loose are more likely to abrade cement. Components with smooth surface finishes do not adhere to cement, place cement under compression and when they become loose they are less likely to abrade cement. When these three stems were evaluated with both smooth and matte finishes the smooth surface finish stems have always demonstrated better results with less loosening and less osteolysis. However some matte finish designs have performed well including the CAD and the HD-2. Whatever prosthesis is utilised all investigators agree that it is optimal to have the prosthesis surrounded by cement, hence the use of centralisers.
Hence today all would agree that the surgeon should use a torsionally sound stem and place an adequate cement mantle around that stem at the time of surgery .If that can be achieved all stems may be equal, however if cement mantle defects are inevitable a smooth surface finish probably has better durability.
The abstracts were prepared by Mrs Dorothy L. Granchi, Course Coordinator. Correspondence should be addressed to her at PMB 295, 8000 Plaza Boulevard, Mentor, Ohio 44060, USA.
