Modeling and finite element analysis of a new revision implant for the elbow

Failed total elbow arthroplasties often are associated with significant bone loss, especially at the level of both humeral condyles. Regular implants might not be ideal for those revision cases and either custom-made implants or complex bone reconstruction procedures with grafts are needed. The goal of the current study was to develop a new revision implant, based on an existing total elbow system (GSB III). The new revision humeral component, with an anterior flange instead of condylar flanges, was designed in a computer-aided design program and virtually implanted in a modeled humerus from a cadaver and subsequently was tested in a finite element model under different loading conditions. The overall distribution of the von Mises stress, as a generalized stress intensity factor, did not differ significantly between the GSB III and the new revision component. There was a tendency that the anterior flange, compared with the condylar flanges, protected the implant-cement-bone interface in the critical region of the distal stem. The finite element analysis suggests that the revision concept for failed total elbow arthroplasties, to rely on existing anterior humerus cortex instead of reconstruction of the condylar bone, seems to have no disadvantage in terms of stress distribution on the implant.