[Use of intraosseous resorbable implants. Experimental evaluation and clinical applications in hand surgery]

The authors report about their experience with the use of absorbable intramedullary nails. After an experimental phase comprising mechanical tests and animal experiments in rabbits, the first clinical applications were for 24 cases of metacarpophalangeal arthrodesis of the thumb. For this indication, bone stabilization was achieved by associating an absorbable intramedullary nail and a metallic oblique pin. Evaluation in animals included, on one hand, a magnetic resonance imaging study, and on the other hand a histological study after the staggered sacrifice of the animals. This histological study was performed on non-decalcified bones by inclusion in methyl methacrylate resin. The mechanical results confirmed the appropriate resistance of these materials for use in the digital skeleton. The histological assessment showed that absorption begins around the 4th month by progressive fragmentation of the material and lasts over 3 years. The encouraging clinical experience and some obstacles encountered during its implementation hav led to two modifications: on one hand, a larger nail was used, on the other hand an absorbable oblique pin was developed, thus ensuring a fully absorbable osteosynthesis.