Biomechanical evaluation of a new technique for external fixation of unstable supracondylar humerus fractures in children

BACKGROUND: Closed reduction and percutaneous pinning is regarded as the treatment of choice for unstable supracondylar humerus fractures, but there are cases in which the use of external fixation is preferable. OBJECTIVE: The aim of this study was to investigate whether the method of external fixation could be considered as a stable alternative to percutaneous pinning and whether there was a difference in stability between two different external fixator constructs. METHODS: Eighteen synthetic humeri were allocated to three groups of six bones each. The specimens of group 1 were fixed by crossed pinning, those of group 2 by a new variation of an external fixator and the specimens of group 3 by an established variation of it. Osteotomy displacement was measured under static loading in internal and external rotation, as well as in extension and flexion. RESULTS: The external fixators proved to be significantly more stable than crossed pinning in sagittal loading. In internal rotation loading the new variation of the external fixator showed the best results. CONCLUSIONS: In case of fractures that can't be replaced by closed reduction the new variation of external fixator should be preferred to the established variation or open reduction and crossed pinning.