FEMORAL REVISION WITH UNCEMENTED TAPERED STEMS: FROM MONOBLOCK TO MODULAR

Aim In revision hip surgery, the use of Wagner SL tapered stem involved serious complications, such as subsidence and dislocation, promoting the development of modular components. Comparative results between monoblock and modular stems are reported. Methods. Since 1992, we have performed uncemented femoral revisions with use of fluted, tapered stems, beginning with Wagner SL monoblock prosthesis (68 cases) followed by Profemur R modular stem (104 cases). The comparison was performed assessing several parameters: stem removal due to infection, revision of the stem for aseptic loosening, occurrence of subsidence and dislocation. Results. Two Wagner prostheses (2.9%) and five Profemur R (4.8%) were removed because of deep infection. No stem required revision for aseptic loosening in both groups. Subsidence of the femoral component was observed in 11 cases treated with monoblock stems (16.1%) and in 3 patients who received modular prostheses (2.9%). In both groups, one stem underwent revision for head-neck disassembly following subsidence. Dislocation occurred in six patients of the Wagner group (9.1%) and in seven hips of the Profemur R group (6.8%). Conclusion. The absence of aseptic femoral stem loosening in both groups documents the validity of fluted, tapered fixation on the diaphyseal cortical bone. The occurrence of serious complications resulted the only reason for further femoral revisions. Modularity promotes the achievement of optimal mechanical behaviour of prosthetic joint. Moreover, availability of the interchangeable neck allows to easily and safely modify intraoperatively the final length and orientation of the prosthesis.