Degradable flexible-connected U-shaped bone nail with muscle and osteoinductive activity

Abstract

The invention discloses a U-shaped bone nail having muscle / bone induction activity and realizing flexible connection after degradation. The U-shaped bone nail is a U-shaped structural member composedof two nail feet and a nail foot connector, and a composite bar comprises titanium alloy spheres, a carbon fiber bundle, a niobium wire layer, a magnesium alloy layer, a zinc alloy layer, a nail footcoating and a nail foot connector coating. The U-shaped bone nail has enough rigidity and strength at the initial stage of an operation; osteoinductive activity is obtained at the contact positions ofthe two nail feet and a bone; and muscle growth inductive activity is achieved at the contact positions of the connector of two nail feet and muscles. After the coatings, zinc alloy and magnesium alloy are degraded, a healed skeletal joint still has high-strength flexible connection in virtue of the carbon fiber bundle and the niobium wire sleeving the carbon fiber bundle; and the titanium alloyspheres at the two ends can fix the carbon fiber bundle, so it is guaranteed that the skeletal joint cannot crack when the skeletal joint is impacted by external force. The invention also provides a preparation method of the U-shaped bone nail having muscle / bone induction activity and realizing flexible connection after degradation. The method has the characteristics of easiness in operation and convenience in industrial production.

Description

technical field [0001] The invention relates to the technical field of new medical materials, in particular to a degraded U-shaped bone nail with muscle and osteoinductive activity and flexible connection. Background technique [0002] At present, the bone nail is a common orthopedic implant connector, and is currently widely used in the treatment of orthopedic diseases. The purpose of U-shaped bone nail is mainly: the connection of two sections of bones after the fracture, although the whole piece of bone is not completely broken but there is a reinforced connection of larger cracks. [0003] There are three types of U-shaped bone screws commonly used at present: one is rigid bone screws made of stainless steel, titanium and titanium alloys, Co-Cr alloys, etc.; the other is rigid bone screws made of biodegradable materials such as polymer materials, magnesium alloys, and zinc alloys. The third is two rigid nail feet and a semi-rigid and semi-flexible bone nail connected el...

AI Technical Summary

Problems solved by technology

However, the mechanical strength of degradable polymer materials is low, and accidents such as fractures often occur during clinical use, which greatly limits the clinical applicability; degradable magnesium alloy bone screws have the problem of excessive degradation, and there are also serious problems. The phenomenon of pitting corrosion causes the material to lose its mechanical support prematurely. Although a large number of literatures have proposed a variety of solutions, there is still the problem of too fast degradation of pitting corrosion, which cannot meet the needs of patients; if zinc alloy is used to make bone nails, It can effectively reduce its degradation rate, but there are problems such as low mechanical strength; if the bimetallic structure of outer zinc and inner magnesium is used to manufacture bone nails, it can not only ensure the mechanical properties but also degrade and disappear after bone healing, but the healed bone is combined It is still a weak link, and there is still a risk of cracking after movement or impact by external forces

[0006] The third type of bone nail uses elastic material at the middle connection of the U-shaped structure, and the healed bone joint is not easy to crack after movement or impact by external force, but it has no rigid fixation effect on the connecting bone at the initial stage of the treatment of orthopedic diseases. , prone to problems such as dislocation of connecting bones, resulting in failure of treatment operations

[0007] The above three types of bone nails all have problems such as no osteoinductive activity and failure to promote the growth of the body at the point of contact with the muscle.

[0008] The patent application number 201811519979.8 discloses a degradable magnesium alloy bone nail with a scaly bone-like nanostructure coating and its preparation method. The bone nail is loaded with a magnesium oxide bioceramic coating with a scale-like bone-like nanostructure from a magnesium alloy matrix. PLGA-bone morphogenetic protein BMP, has a certain osteoinductive activity and the material can be degraded, but there are the following problems: ①The healed bone junction is a weak link. There is still a risk of cracking after the impact; ②If the U-shaped bone nail is made, there will be no muscle growth-inducing activity at the place where the middle connection of the U-shaped structure contacts the muscle; Corrosion and degradation are very easy to occur in the medium, and the mechanical properties are reduced. When the human bone is not completely healed, it will lose the mechanical support prematurely, which makes it difficult for the magnesium alloy bone nail to match the growth and healing speed of human bone tissue and collapse prematurely. Moreover, AZ31 magnesium After the alloy is degraded, the Al element contained in it will be released. Al element is neurotoxic and harmful to the human body; ④ has no antibacterial effect, and bacterial infection is prone to occur around the bone nail, causing great pain to the patient

[0009] The patent application number 201810865873.7 discloses a biodegradable composite rod for medical implantation and its preparation method. The innermost layer is a magnesium alloy, the middle layer is a zinc alloy, and the outermost layer is a coating layer with osteoinductive activity. It has achieved the functions of high mechanical properties, moderate degradation speed, and osteoinductive activity, but there are the following problems: ①The healed bone joint is a weak link. There is still a risk of cracking after being impacted by external force; ②If a U-shaped bone nail is manufactured, there will be no muscle growth-inducing activity at the place where the middle connection of the U-shaped structure contacts the muscle; ③Both magnesium alloys and zinc alloys do not contain antibacterial agents. Copper ions or silver ions are prone to bacterial infection around the bone nail, causing great pain to the patient

[0010] The patent application number 201820894568.6 discloses a U-shaped bone nail for fixing small fracture fragments, which uses an elastic connector to press on the small fracture fragments to realize the connection between the small fracture fragments and the main bone to ensure firm and reliable fixation of the fracture. There are the following problems: ①There is no rigid fixation effect on the connecting bone at the initial stage of the treatment operation, and the dislocation of the connecting bone is prone to occur, resulting in surgical failure; ②There is no osteoinductive activity at the contact between the two nail feet and the bone, and there is no muscle growth at the contact between the connecting body and the muscle Inducing activity, which is not conducive to bone healing and muscle growth; ③There is no antibacterial effect, and bacterial infection is prone to occur around the bone nail, causing great pain to the patient

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