A Novel Implant Regarding Transcondylar Humeral Fractures Stabilization. A Comparative Study of Two Approaches

Abstract

The osteosynthesis of transcondylar humeral fractures is an important branch of the upper limb traumatology. The bone- implant assembly has to be strong enough to resist the high loads arising during the early rehabilitation program, while keeping the soft tissue stripping to a minimum. Using the finite element method, this study compares two alternatives of stabilization of this kind of fractures by means of a new type of implant, less expensive than the existing locking plates and, more importantly, minimally-invasive. This implant comprises two modified cortical screws (one for each column of the distal humerus) and a Kirschner wire (or a partial threaded screw) which locks the screws transversally at the epiphysis. The screws can be placed in the middle of the columns of the distal humerus or with an eccentricity, immediately under the cortical shell of the bone. Using data from distal humerus CT scans, two CAD (Solidworks) models of the bone and implants were produced, imported, edited, loaded and analysed in a finite element analysis program (Ansys). The results indicate that the subcortical placement of the screws is more favorable than the intracancellous one, leading to increased stiffness of the bone-implant assembly. This stage the first refinement of this method and this study will be followed by computer, in-vitro and clinical studies, comparing the behavior of this alternative to the existing standard implants.