CN-122016465-A - Biomechanical experimental method of novel magnesium controlled-release dynamic intramedullary nail

Abstract

The invention relates to a biomechanical experimental method of a novel magnesium controlled-release dynamic intramedullary nail, which comprises an intramedullary nail, an anti-withdrawal bolt, a substance exchange hole and a gasket, wherein the surface of the intramedullary nail is provided with two holes which are arranged up and down, the upper hole is the anti-withdrawal bolt, the lower hole is the substance exchange hole, the gasket is inlaid in the middle of the surface of the intramedullary nail, a magnesium controlled-release-dynamic compression coupling mechanism is provided for the first time, a degradable material technology is combined with an orthopaedics internal fixation dynamic idea, a magnesium alloy gasket structure is innovatively designed, the automatic dynamic compression of the intramedullary nail is realized, the intramedullary nail dynamic does not need secondary operation, the innovative application of magnesium alloy in large orthopaedics implants is opened, and the application field of degradable materials is expanded.

Inventors

• SHA WEIPING
• SHENG XIAOLEI
• XU ZHI
• QIAN JIAYU

Assignees

• 张家港市第一人民医院

Dates

Publication Date

20260512

Application Date

20260127

Claims (3)

1. 1. A biomechanical experimental method of a novel magnesium controlled-release dynamic intramedullary nail is characterized by comprising an intramedullary nail (1), an anti-withdrawal bolt (2), a substance exchange hole (3) and a gasket (4), wherein the surface of the intramedullary nail (1) is provided with two holes in an up-down mode, the upper hole is the anti-withdrawal bolt (2), the lower hole is the substance exchange hole (3), and the gasket (4) is inlaid in the middle of the surface of the intramedullary nail (1).
2. 2. The biomechanical experimental method of the novel magnesium controlled-release dynamic intramedullary nail according to claim 1, wherein the gasket (4) is made of degradable magnesium alloy, the thickness of the gasket (4) is 1mm to 2mm, and the diameter of the gasket (4) is the same as the diameter of the intramedullary nail (1).
3. 3. The biomechanical experimental method of the novel magnesium controlled release dynamic intramedullary nail according to claim 1, comprising the following steps: 1. the overall design of the technical route is that the method adopts a technical route of theoretical simulation, experimental verification and optimization improvement, and the biomechanical property of the novel magnesium controlled-release dynamic intramedullary nail is systematically evaluated by a method combining finite element numerical simulation and physical mechanical test; 2. early work basis and finite element model optimization ① The preliminary finite element analysis work of the novel magnesium controlled release dynamic intramedullary nail is completed, a three-dimensional finite element model of the intramedullary nail-femur system containing a magnesium alloy gasket is established, and the feasibility of a dynamic compression mechanism is preliminarily verified; ② The finite element model is further optimized, namely, on the basis of early work, the finite element model is optimized and perfected from the following aspects in the research; 3. Design of physical mechanics experimental scheme ① Sawbones femur model selection a fourth generation synthetic femur model (model 3406) manufactured by PACIFIC RESEARCH Laboratories; ② Preparing an intramedullary nail, namely preparing a traditional control group intramedullary nail and an experimental group intramedullary nail (1); ③ The preparation process of the magnesium alloy gasket (4) comprises the steps of adopting a vacuum induction smelting process to prepare an Mg-3Zn-0.5Ca alloy ingot, wherein the smelting temperature is 720+/-10 ℃, and the protective atmosphere is SF6+CO2 (volume ratio is 1:99); ④ Establishing a fracture model, namely using a standardized femoral shaft middle section traversing fracture model; ⑤ Intramedullary nail implantation operation, namely performing intramedullary nail implantation by referring to clinical standard operation; 4. Mechanical property testing method ① Static mechanical test, namely using an Instron E10000 electronic universal tester to carry out static mechanical test, wherein the test environment temperature is 20+/-2 ℃ and the relative humidity is 45-75%; ② Dynamic fatigue test, namely designing a fatigue test scheme according to ISO 7206-4 standard to carry out fatigue loading; 5. Magnesium alloy degradation behavior monitoring ① Establishing a standardized in-vitro degradation experimental environment and monitoring degradation indexes; ② The dynamic compressive force monitoring system is characterized in that a special dynamic compressive force monitoring device is designed to monitor the axial displacement and the compressive force change of the intramedullary nail in the degradation process of the magnesium alloy gasket in real time; 6. Contrast analysis and verification method ① Comparing the finite element result with experimental data, namely establishing a verification scheme of the system to ensure the reliability of the finite element analysis result; ② The statistical analysis method is to process experimental data by a strict statistical method; ③ Quality control measures, namely adopting blind method evaluation, standardized operation, equipment calibration, data check and traceability record measures; 7. expected technical index validation And (5) respectively carrying out mechanical property index verification, dynamic compression effect verification and safety index verification, and sorting and archiving verification data.

Description

Biomechanical experimental method of novel magnesium controlled-release dynamic intramedullary nail Technical Field The invention relates to the technical field of medical treatment, in particular to a biomechanical experimental method of a novel magnesium controlled-release dynamic intramedullary nail. Background Femoral shaft fracture is a common traumatic disease in orthopaedics clinic, and accounts for about 6% of total body fracture, and is mostly seen in high-energy traumas such as traffic accidents, falling injuries and the like. With the rapid development of global transportation industry and the acceleration of population aging process, the incidence of femoral shaft fracture tends to rise year by year. The intramedullary nail internal fixation is used as a 'gold standard' for treating femoral shaft fracture, has the advantages of small trauma, reliable fixation, quick healing and the like, and has been widely applied in clinic. However, conventional intramedullary nails employ a static fixation pattern, while providing good initial stability, there is still a problem of high fracture nonunion rates in certain complex fracture types. The literature reports that the rate of nonunion for surgical treatment of femoral shaft fractures is 4.6-13.9%, with complex fracture types (such as type B and type C fractures) being an independent risk factor for postoperative nonunion. The fracture nonunion not only brings long-term pain to the patient, but also requires multiple operation treatments, and has high medical cost and heavy burden to families and society. In recent years, biomechanical studies of fracture healing have shown that moderate micro-stimulation has an important role in promoting callus formation and fracture healing. Perren et al, teach that a strain of 2-10% at the fracture end favors callus formation, while excessive rigid fixation rather inhibits fracture healing. The theory lays a foundation for the establishment of a dynamic fixation concept. Traditional dynamic fixation is mainly realized through operation in operation, such as dynamic screws and the like, but the operation is complex, the timing is difficult to grasp, and the clinical application is limited. The intelligent intramedullary nail system developed by Orthofix company is actively explored in the aspect of dynamic fixation, and adopts the shape memory alloy technology to realize delayed compression, but the technology is complex, the operation complexity and the technical requirement are higher, and the clinical application of the intelligent intramedullary nail system can be influenced. Although the absorbable screw technology of Smith & Nephew Endoscopy corporation solves the problem of secondary surgery to some extent, the degradation time is difficult to control accurately and the clinical effect is limited. The static fixation mode of the traditional intramedullary nail can not meet the treatment requirement of complex fracture under the condition of current research at home and abroad, and the development of a novel dynamic intramedullary nail system is an important direction of the development of the current orthopedic internal fixation technology, however, the existing dynamic fixation technology generally has the problems of complex operation, high cost, uncertain effect and the like, and the development of a simpler, more convenient, efficient and controllable dynamic fixation system is needed. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides a biomechanical experimental method of a novel magnesium controlled-release dynamic intramedullary nail, which firstly provides a 'magnesium controlled-release-dynamic compression' coupling mechanism, combines a degradable material technology with an orthopaedics internal fixation dynamic idea, innovatively designs a magnesium alloy gasket structure, realizes automatic dynamic compression of the intramedullary nail, does not need secondary operation in intramedullary nail dynamic, opens up innovative application of magnesium alloy in large-scale orthopaedics implants, and expands the application field of degradable materials. In order to achieve the aim, the biomechanical experimental method of the novel magnesium controlled release dynamic intramedullary nail comprises the intramedullary nail, an anti-withdrawal bolt, a substance exchange hole and a gasket, wherein the surface of the intramedullary nail is provided with two holes which are arranged up and down, the upper hole is the anti-withdrawal bolt, the lower hole is the substance exchange hole, the gasket is inlaid in the middle of the surface of the intramedullary nail, the anti-withdrawal bolt plays a role in preventing the extraction of the intramedullary nail, and the substance exchange hole is used for facilitating the outflow of liquid after magnesium metal degradation. As a further improvement scheme of the invention, the gasket is made of degradable magnesium allo