A bone fixation device composed of degradable bone plate and non-degradable bone nail

Abstract

The invention discloses a bone fixing apparatus combining a degradable bone plate and a non-degradable bone nail. The bone fixing apparatus is composed of a bone plate, a bone nail and a bone nail sheath, wherein the lower surface of the bone plate is matched with outline of a fracture part; a round hole is formed in the bone plate, and the bone plate is made from a degradable material; the bone nail is made from a non-degradable material; the bone nail sheath is of a cylindrical structure which is provided with a column cap at the upper end and symmetrically provided with two expansion slots at the lower end; the cylindrical structure is provided with a central screw hole which is matched with the bone nail; the bone nail sheath is made from polylactic acid; the bone nail runs through the central screw hole of the bone nail sheath and is fixedly connected to the fracture part; meanwhile, the bone nail sheath expands to be fixed together with the bone plate through outer supports of the expansion slots at the lower end of the bone nail sheath. The bone fixing apparatus disclosed by the invention has the advantages of being simple in structure and easy to implement; the degradable bone plate can be corroded and degraded in vivo, and degradation products are non-toxic, and can be excreted out of body through metabolism, so as to avoid secondary trauma caused by a second operation; and through the non-degradable bone nail, the bone fixing apparatus can guarantee a fixing strength of bones in a healing period.

Description

technical field [0001] The invention relates to an orthopedic medical device, in particular to a bone fixation device composed of a degradable bone plate and a non-degradable bone nail. Background technique [0002] At present, the materials clinically used for intraosseous fixation are mainly metal materials, such as internal fixation plates, screws, rods, and intramedullary nails. The reason is that metal materials have good mechanical properties and can achieve early strong fixation, especially for load-bearing bones. The curative effect is reliable and has been accepted by people. However, due to the mismatch of mechanical properties, the elastic modulus of metal internal fixation materials is 10-20 times that of human compact bones such as long bones and femurs, and the mechanical properties cannot change dynamically with the bone healing process, resulting in the medical "stress shielding effect". Lead to osteoporosis or bone degeneration, affect the strength of bone...

AI Technical Summary

Problems solved by technology

[0005] However, the current problem faced by magnesium alloys is that the corrosion degradation rate is too fast, which leads to rapid decay of mechanical properties, which cannot match the rate of bone healing, that is, it cannot maintain sufficient strength until the bone is completely healed, especially for magnesium alloys. Bone screws will undergo rapid degradation, especially the faster degradation rate of the threaded part, and the threaded part becomes flat due to degradation, which may lead to a decrease in the fastening force of the bone screw, resulting in the failure of the entire bone fixation system

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