FATIGUE TESTING OF INTRA-MEDULLARY RECONSTRUCTION FEMORAL NAILS

摘要

Reconstruction intra-medullary femoral nails have been effectively used for treatment of fractures of femur. They have been shown to have biomechanical benefits compared to extra-medullary devices. Intra-medullary nails have to transfer appreciable static and dynamic loads. Simultaneously, severe criteria of fatigue fracture resistance and corrosion has to be met. Development of nails includes both the improvement of design features and experimental determination of nail properties. Finite element method has been currently used for optimalization of nail design, e.g. [1]. As regards the testing standards for particular implants, they may not exist or need to be modified, because of wide variance of implants, different engineering design features and materials. Fatigue properties of nails have been experimentally evaluated according to the ASTM F384 standard as a static and dynamic compression test in a single axis fatigue machine e.g. [2]. The other possible way is to perform experiments in terms of the standard for determination of endurance properties of stemmed femoral components without application of torsion, e.g. [3]. The aim of this work is to determine fatigue endurance of reconstruction intra-medullary femoral nails developed and produced by the Czech joint-stock company MEDIN, to compare fatigue lifetime of nails made of steel of different strength and to develop details of the fatigue testing procedure suitable for reconstruction intra-medullary femoral nails.