Orthopedic implant device

Abstract

The invention discloses an orthopedic implant device which comprises an intramedullary nail main body which is of a core-shell structure, the bending strength of a main body core is improved by laminating a continuous fiber composite material, and the torsional strength of a main body shell is improved by a continuous fiber composite material which is obliquely arranged with the main body core. An expansion containing cavity is formed in a sealing cap hole of the intramedullary nail main body, meanwhile, a taking-out unit forms an expansion structure, the surface of the expansion structure is attached to or partially attached to the side wall of the expansion containing cavity, the shearing stress area is increased through the arrangement, and the requirement for the shearing strength of materials is correspondingly lowered; meanwhile, a clamping force is formed between the expansion structureand the expansion containing cavity, and the resultant force application of the clamping force avoids the phenomenon that when a taking-out unit in the prior art is applied to an intramedullary nail main body prepared from a continuous fiber composite material, a stressed part is located at a thread with low shear strength, and consequently the thread is broken and / or expanded.

Description

technical field [0001] The invention relates to the technical field of medical devices, in particular to an orthopedic implant device in which the main body of an intramedullary nail is made of a laminated continuous fiber composite material. Background technique [0002] In current orthopedic implants, the intramedullary nail is usually composed of a main body of the intramedullary nail, a lag screw and a fixation screw. Its material is made of stainless steel and titanium alloy metals with better biocompatibility. This type of material generally has high strength and high modulus (it will cause stress shielding after implantation), and it can be visualized under X-ray (in bone fusion). The surface is easy to cause artifacts), and the fatigue performance is average (there is generally a 9% fracture rate of orthopedic implants in clinical practice). It can be used to locate and fix fractures of long bones such as the femur. In a fractured femur, the main body of the intrame...

AI Technical Summary

Problems solved by technology

However, the above-mentioned intramedullary nail extractor is only suitable for intramedullary nails made of metal materials. For intramedullary nails made of continuous fiber composite materials, especially in order to ensure the bending strength, the lamination (the laying direction of the continuous fiber composite fibers and the Intramedullary nails made of continuous fiber composite materials when the included angle of the screw hole axis is 0°-45°), the laminated structure makes the shear strength of the thread in the screw hole very low, using the above extractor When the force is placed on the thread with low shear strength, the thread will collapse and / or spread, making it difficult for the above extractor to be used for intramedullary nails made of continuous fiber composite materials.

As another example, U.S. patent document US10028777B2 discloses a bone implant, which includes a matrix formed by a fiber-reinforced polymer, especially an intramedullary nail structure. In order to remove the intramedullary nail, this document discloses two removal structures, Dovetail barb structure and T-shaped structure, among them, the dovetail barb structure needs to open a new hole in the matrix, at this time, the hole is easy to grow into the bone tissue, making it difficult to remove the intramedullary nail, while the T-shaped structure requires A cavity with a notch is processed in the mounting hole of the nail tail cap, so that the T-shaped bar extends into the inner cavity, rotates and locks, and then pulls outward to take out the intramedullary nail. However, the structure of the T-shaped bar will be in the screw If there is a gap in the tooth part, the strength of the thread will decrease. The thread strength of the layered fiber composite material itself is very low, so the probability of tooth collapse during processing and use is very high, and the T-shaped bar cannot completely match the inner cavity. , when in use, the activity space is large, which is easy to cause relative shaking or sliding, and because the matrix is ​​formed of laminated fiber-reinforced polymers, the T-shaped structure has only 2 stress points and the contact area is small, and it is easy to tear the inside cavity wall, causing damage to the intramedullary nail

In summary, it can be seen that the existing intramedullary nails have a better effect on the extraction of metal intramedullary nails, but for intramedullary nails formed of continuous fiber composite materials, the use of existing extractors or extraction devices It is easy to cause the cap installation hole of the intramedullary nail to break or break

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