FEMORAL COMPONENT REVISION USING A WAGNER DIAPHYSEAL FIXATION STEM

Abstract

Introduction and Objectives: Severe proximal femoral defects are a major problem in femoral stem revision surgery. Various surgical techniques have been described that aim to resolve the deficit of bone stock: the Exeter technique or impacted allograft bone, long porous surface distal fitting stems, stems coated with hydroxyapa-tite, and modular stems with metaphyseal fixation. In 1987, Wagner presented a revision technique using a long distal fitting conical stem with excellent proximal bone regeneration. However, the Wagner stem presents two fundamental problems: subsidence and dislocation. Furthermore, it is a demanding technique that requires preoperative planning. Conical fixation makes adjustment of length and anteversion more difficult, as it is dif-ficult to change these parameters after impaction.

Materials and Methods: This is a retrospective study of the first 86 Wagner prostheses implanted at our centre.

Results: The reason for revision was aseptic loosening in 81.8% of cases. A morselised bone graft was used in the femur in 22% of cases. Average follow-up period was 6.5 years. Complications occurred in 33% of cases. Half of these complications were perioperative fractures of the femur, which for the most part required no additional treatment besides intervention during the operation. Of the 6.8% of implants that were loose, only 3 cases required surgical treatment. Subsidence occurred in 40.9% of implants, with a median of 13.5mm. Of the 40.9% of implants that sank, two-thirds sank more than 0.5cm. Average metal-bone contact was 27.57mm postoperatively, 39.9mm at one year postoperatively, and 50.38mm at final evaluation.

Discussion and Conclusions: The Wagner prosthesis has yielded good results in revisions with proximal bone defects. However, it presents a high rate of dislocation and subsidence, in relation to the technical demands of the procedure.