Intramedullar osteosynthesis implant used, eg, for the fixing of finger or toe interphalangeal joints damaged by osteoarthritis, made of memory material and expanding at body temperature to provide a secure grip

摘要

An intramedullar osteosynthesis implant, permitting arthrodesis of a joint or diaphysary osteosynthesis of an upper or lower limb comprising two groups of at least two prongs extending either side of a central zone, which are parallel at ambient temperature which are intended to be implanted in the medullary canal of a diaphysis and are made of memory material in such a way that at body temperature they spread out an lock into the canal. At body temperature the prongs spread apart in the same plane. In an alternative version comprising two sets of three prongs, the outer prongs spread apart in the same plane and the central prong in a direction perpendicular to it. At ambient temperature the planes of each group of prongs form an angle of 0-60degrees and preferably about 10degrees. The ends of the prongs may be chamfered. The length of the pairs of prongs may differ, the longer pair being intended for implant into the joint or the proximal diaphysis. The implant is implemented in a titanium-nickel alloy. This comprises 50-60 % titanium and 40-50% nickel. It is preferably 55% titanium and 45% nickel.