Revision Total Hip Arthroplasty: The Femoral Component.
The initial results with cemented femoral revision stems were disappointing, with high early loosening rates. The application of second-generation cementing techniques improved results markedly, with loosening rates of 10% at 10 years in a number of series. Bone quality and patient age also appear to be important factors in predicting the success with a cemented revision stem. The use of a long stem is not necessary to obtain these improved results. On the basis of early reports, a recently described technique in which a revision stem is cemented into impacted cancellous allograft appears promising. Results with proximally coated uncemented revision stems have been variable, with failure rates of 4% to 10% reported at only 2 to 4 years. Initial stability must be obtained if proximal coating is to be utilized. Extensively coated revision stems provide initial stability through an interference fit between the porous coating and the diaphysis. With this technique, 10-year survival rates of 90% have been achieved, and the clinical results appear to be equivalent to those obtained with cemented revision stems and modern cementing techniques. Diaphyseal fixation has also been achieved without porous coating, either with modular revision stems or with long, textured titanium stems. Isolated early reports with such stems have been promising, but 10-year results are not yet available.