Finite element analysis of intramedullary nails designed with new locking nail fixation for tibial fractures

Finite element analysis of intramedullary nails designed with new locking nail fixation for tibial fractures | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Finite element analysis of intramedullary nails designed with new locking nail fixation for tibial fractures Jiang Wu, Mingmang Pan, Junchao Huang, Haijun Xiao, Shanhong Qi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4377543/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective: The potential instability of tibial fracture fixation with intramedullary nails due to gap coordination between locking nails and holes was investigated. The aim of this study was to explore a more stable and reliable internal fixation method using intramedullary nails designed with new locking mechanisms. Methods: Tibial CT image data from a healthy female were obtained to create a tibial fracture model in the middle section using finite element digital technology. Subsequently, two different intramedullary nails were utilized for fixation. The experimental group employed intramedullary nails designed with new locking mechanisms, while the control group used conventional intramedullary nails. The specimens were subjected to axial loading of 2500 N, lateral bending of 1000 N, and rotational forces of 15 Nm. The maximum stress and displacement of the bone and internal fixation were recorded for both groups. Results: Under an axial stress of 2500 N, the maximum stress on the internal fixation in the experimental group was 247.0 MPa, with the maximum displacement of the fracture end reaching 0.200 mm. In the control group, the maximum stress on the internal fixation was 434.9 MPa, and the maximum displacement of the fracture ends was 0.538 mm. For a lateral bending stress of 1000 N, the maximum stress on the internal fixation in the experimental group was 678.0 MPa, and the maximum displacement of the fracture end was 0.255 mm. In the control group, the maximum stress on the internal fixation was 413.7 MPa, and the maximum displacement of the fracture end was 0.826 mm. When subjected to a rotational stress of 15 Nm, the maximum stress on the internal fixation in the experimental group was 626.8 MPa, with the maximum displacement of the fracture end measuring 0.839 mm. In contrast, the control group exhibited a maximum stress of 289.1 MPa on the internal fixation, along with a maximum displacement of the fracture end of 1.802 mm. Conclusion: Compared with traditional intramedullary nail designs, the new intramedullary nail design provides superior mechanical support for middle tibial fractures and offers more biomechanical advantages. Tibial fracture Finite element analysis Tibial intramedullary nai Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Currently, common treatments for tibial fractures include internal fixation by locking plates and interlocking intramedullary nails. Interlocking intramedullary nail internal fixation offers advantages such as a reduced risk of local skin necrosis and exposure of the internal fixator due to minimal soft tissue manipulation. [ 1 – 2 ] However, the distal end of the existing intramedullary nail suffers from low precision, leading to the adoption of a design featuring a gap between the keyhole and the locking nail to increase locking success rates. Unfortunately, this design compromises the stability of intramedullary nail fixation. [ 3 – 5 ] Our Orthopedics department has been dedicated to intramedullary nail research since 2010, resulting in the development of a novel fully locked interlocking intramedullary nail. This locking nail exhibited an oval smooth rod structure with an elliptical cross-section, while the intramedullary nail keyhole was also oval in shape. When the locking nail is inserted into the intramedullary nail keyhole, it becomes integrated through rotational locking, thereby improving fracture fixation stability (Fig. 1 ). To improve the success of distal locking nails during surgical procedures, we devised specialized surgical targeting instruments that streamline the operation, facilitating precise distal locking. This study employed finite element analysis to validate the mechanical properties and compare the stiffness and stability of intramedullary nails designed with new locking mechanisms (experimental group) and with those of conventional intramedullary nails (control group) in tibial fracture fixation. Methods Experimental subjects A healthy adult female, 50 years of age, with a height of 170 cm and a weight of 65 kg, was selected from Tinglin Hospital, Jinshan District, Shanghai. Individuals with a history of bone diseases related to fractures, osteoporosis, pathological fractures, disuse atrophy, or other bone-related conditions were excluded. Experimental instruments and software 64-slice spiral CT (Siemens, Germany); Mimics 21.0 (The Materialise Group, Leuven, Belgium) 3-Matic Research 13.0 (The Materialise Group, Leuven, Belgium) SolidWorks 2021 (DS Solidworks Corp, Waltham, MA, USA) Hypermesh 13.0 (Altai Engineering) Abaqus 6.13 (Simulia Corp., Providence, RI, USA) Establishment of a 3D tibia model The entire tibia segment was subjected to scanning using a 64-slice spiral CT scanner to acquire two-dimensional transverse images. The resulting two-dimensional image data were saved in Dicom format, and the medical image processing software Mimics 21.0 was utilized. The data were imported into Mimics 21 software, and the tibia mask was constructed through three-dimensional reconstruction methods, including thresholding and multiple-slice editing. The generated model was saved in STL format for future reference. A Handyscan307 3D scanner (Creaform, Canada) was used to perform 3D scans of intramedullary nails and screws, yielding point cloud data. The internal fixation 3D model was constructed using reverse engineering techniques and assembled in SolidWorks 2021. Subsequently, the internal fixation model was exported in iges format and meshed in Hypermesh 13.0 with a mesh size of 0.5 mm. The finalized internal fixation model was then exported in STL format. The STL models of the tibia and internal fixation were imported into 3-Matic Research 13.0 software for surgical planning. Initially, a 5 mm long fracture defect was created in the middle of the tibia to generate the tibia fracture model sample. Subsequently, with guidance from orthopedic surgeons, the internal fixator was positioned on the tibial model to simulate the procedure for internal fixation in tibial fractures. After the internal fixation was correctly placed, a Boolean operation was executed to obtain the postoperative tibial model. Following this, both the tibia model and the internal fixation model were brought into Hypermesh 13.0 for mesh optimization and the generation of solid meshes. In accordance with prior research[6], a mesh size of 1 mm was applied to the tibia, while a mesh size of 0.5 mm was used for internal fixation. After assessing the surface mesh quality within Hypermesh 13.0 (Altair Engineering), the model was divided into C3D4 solid units[1]. The solid cell model was subsequently exported to Abaqus 6.13 (Simulia Corp.) for further configuration of boundary conditions and finite element analysis. It was assumed that all the bone and implant models exhibited linear elastic properties. To assign material properties to each element, the apparent density (ρ), Young's modulus (E), and Poisson's ratio were determined based on the Hu values obtained from the CT scan. The following distinct formulas were applied for cortical bone and cancellous bone. The material properties of the bone were assigned using the grayscale method, with the assignment formula referring to previous research[7]. Digital production of tibial internal fixation In line with the anatomical fracture model and the AO fracture fixation principles, a tibial intramedullary nail measuring 10*320 mm in size and length (provided by Dabo Company) was chosen, featuring distinct designs for the intramedullary nail keyhole. Creation of Locking Screws: Different screws were utilized for fixation, and various screw lengths were crafted to accommodate specific requirements. Assembly of Components: Within the Creo software, the tibia model and tibia intramedullary screws were selected. Subsequently, the tibia and the components were assembled with intramedullary screws following the coordination instructions. As per the conventional surgical plan and clinical experience, three locking screws were employed for securing the proximal fracture, while two locking screws were used for fixing the distal fracture. Appropriate-length screws were employed in the assembly of the two distinct intramedullary nails for the tibia. This procedure resulted in an experimental group (comprising intramedullary nail with the new locking nail design) and a control group (comprising traditional intramedullary nail). ( Fig.2 ) Material parameters The material properties assigned to all intramedullary nails and locking nails were based on titanium (Ti-6 L-4 V), characterized by a Young's modulus (E) of 110,000 MPa and a Poisson's ratio of 0.3. [8-9] To simulate the mechanical nature of these implants, the interfaces between the new locking nail and intramedullary nail (experimental group) and between the screw and bone (control group) were tied, while the others were set to slide contact. The interfaces between the intramedullary nail and bone (experimental group and control group), locking nail and intramedullary nail (control group), and new locking nail and bone were set with a friction coefficient of 0.3. [10-11] Loading loads and constraints In accordance with previous relevant literature, forces were applied to simulate the tibial platform conditions. Vertical force of 2500 N was applied with the lower tibial end fixed, with 60% distributed on the lateral side and 40% on the medial side. A load of 1500 N was applied to the medial tibia platform, along with 1000 N on the lateral tibia platform [12]. In the lateral bending experiment, both ends of the tibia were immobilized, and a uniform 1000 N force was applied to the tibia's side [13]. For rotational force testing, the lower tibia was secured, and a 15 Nm clockwise torque was applied to the tibia platform [14]. Changes in the stress and displacement of the tibial fracture model were observed under these three force loading conditions. Main observation indicators This study focused on two groups of patients utilizing different intramedullary nails for the fixation of middle tibial fractures. The key observation parameters included the maximum stress and displacement within the internal fixation and the maximum displacement at the fracture's broken end. These parameters were evaluated and compared between the two groups. Results Axial load of 2500 N Under an axial load of 2500 N, the maximum stress experienced by the specimens in the experimental group was 247.0 MPa, with a maximum displacement of the fractured end measuring 0.200 mm. In contrast, the control group exhibited a maximum stress of 434.9 MPa and a maximum displacement of broken ends measuring 0.538 mm.( Table 1 and Fig.3) Table 1 Maximum stress (MPa) and displacement (mm) of the middle tibial fracture model under the axial 2500 N stress condition Experimental group Control group Bone Intramedullary nail Screws Bone Intramedullary nail Screws Stress 122.9 247.8 202.8 111.2 434.9 73.5 Displacement 3.607 3.305 3.412 3.861 3.300 3.682 Displacement of broken end 0.200 0.538 Lateral bending stress of 1000 N Under a lateral bending stress of 1000 N, the experimental group exhibited a maximum stress of 678.3 MPa, with a maximum displacement at the fracture end of 0.255 mm. In contrast, the control group displayed a maximum stress of 413.7 MPa, accompanied by a maximum displacement at the fracture end of 0.826 mm. ( Table 2 and Fig. 4) Table 2 Maximum stress (MPa) and displacement (mm) of the middle tibial fracture model under a lateral bending stress condition of 1000 N Experimental group Control group Bone Intramedullary nail Screws Bone Intramedullary nail Screws Stress 160.7 454.2 678.3 310.9 413.7 249.5 Displacement 8.610 8.500 8.387 9.485 9.267 9.499 Displacement of broken end 0.255 0.826 Rotational stress of 15 Nm Under a rotational stress of 15 Nm, the experimental group exhibited a maximum stress of 626.8 MPa, with a maximum displacement at the fracture end of 0.839 mm. In contrast, the control group displayed a maximum stress of 289.1 MPa, accompanied by a maximum displacement at the fracture end of 1.802 mm. ( Table 3 and Fig. 5) Table 3 Maximum stress (MPa) and displacement (mm) of the middle tibial fracture model under the rotational 15 Nm stress condition Experimental group Control group Bone Intramedullary nail Screws Bone Intramedullary nail Screws Stress 168.6 626.8 515.7 355.2 264.6 289.1 Displacement 3.349 1.831 3.323 5.983 2.778 5.935 Displacement of broken end 0.839 1.802 Discussion Tibial fractures often result from severe direct injuries. In the past, treatments such as plaster fixation, traditional open reduction with plate internal fixation, and external fixation with stent fixation frequently led to complications, including ankle joint stiffness, local infections, wound necrosis, nail tract infections, delayed fracture healing, and deformities. These approaches often yield unsatisfactory results[ 15 ]. Currently, minimally invasive percutaneous plate osteoplasty (MIPPO) is a widely employed surgical technique in the clinical management of such fractures. MIPPO helps reduce the extent of soft tissue damage to some extent[ 3 ]. However, not all tibial fractures are suitable for plating, especially those involving severe soft tissue damage and poor skin conditions. Plate implantation may carry risks of skin irritation, incision infections, local skin necrosis, and plate exposure, among other complications[ 4 ]. Furthermore, the process of plate internal fixation typically involves the removal of additional soft tissue, which disrupts blood flow around the fracture site and can adversely affect fracture healing[ 16 ]. Intramedullary nailing represents another effective method for stabilizing distal tibial fractures. Numerous studies have demonstrated that the use of intramedullary nails aligns with the prevailing trend of minimally invasive treatment and the concept of biological osteosynthesis (BO). This approach results in reduced local soft tissue trauma and fewer postoperative complications, such as soft tissue necrosis and osteomyelitis, garnering increased attention in its application. In fact, the surgical indications for interlocking intramedullary nails have expanded to encompass some distal tibial fractures. Nevertheless, the clinical utilization of interlocking intramedullary nail technology has faced scrutiny, primarily concerning its ability to effectively maintain fracture stability. The key point of contention lies in the accuracy of locking achieved by existing distal intramedullary nail technology. Currently, there is a certain gap between the keyhole and the locking rod (typically approximately 0.3–0.5 mm), impacting interlocking intramedullary nail fixation. While this gap-fitting approach between the keyhole and the locking nail enhances the locking nail's success rate, it diminishes fixation stability. The resulting interaction between the locking nail and the intramedullary nail yields relatively stable fixation, but this approach does not strictly adhere to the concept of BO. For distal tibial fractures located within 5 cm of the ankle surface, the interlocking effect is further compromised due to the limited working distance of the distal end of the intramedullary nail. In particular, the large size of the distal tibial medullary cavity, strong muscle tension, relatively slender intramedullary nails, and possibility of slippage between the intramedullary nail and the locking nail can lead to suboptimal control of fracture angles and an increased risk of coronal angle displacement. Therefore, despite the mechanical advantages associated with intramedullary nailing, its clinical effectiveness in managing distal tibial fractures remains a subject of debate[ 17 – 18 ]. To enhance the stability of intramedullary nailing in the treatment of tibial fractures, Krettek introduced the Poller nailing technique in 1999[ 19 ]. This technique involves the placement of 1–2 blocking screws in close proximity to the intramedullary nail to prevent wobbling within the medullary canal. In recent years, as intramedullary nail design has continued to advance, the utilization of specialized intramedullary nails for distal tibial fractures has gained popularity. These nails feature a flat distal end with the keyhole positioned just 5 mm from the nail tip. This design shortens the gap between the keyhole and the nail tip, enabling multiplanar locking. These advancements expand surgical indications, increase fracture fixation stability, and effectively address fractures within 5 cm of the ankle joint surface. To enhance stability, additional measures such as fibula internal fixation and cast external fixation may be needed. While these approaches improve the stability of tibial fracture fixation to some extent, they also increase surgical trauma. Nevertheless, further improvements are needed to enhance the stability of the internal fixation[ 16 , 19 – 20 ]. In response to the aforementioned factors, our hospital's Orthopedics Department introduced a newly designed locking intramedullary nail fixation system and developed a corresponding aiming and fine-tuning device. The locking nail featured an elliptical smooth rod structure with an elliptical cross-section, and the keyhole of the intramedullary nail was similarly designed to be oval. When the locking nail was inserted into the keyhole, a rotational locking mechanism integrated the locking screw with the intramedullary nail, thereby enhancing fracture fixation stability. To improve the success rate of distal locking nail placement during surgery, specialized surgical targeting instruments were used to streamline the procedure and ensure precise distal locking. In this study, a middle tibial fracture model was created using the finite element method, simulating tibial fracture fixation with two types of implants in the experimental group (new intramedullary nail) and the control group (traditional intramedullary nail). First, under an axial load of 2500 N, akin to the forces experienced during strenuous activities such as running and jumping, the performance of both experimental models was assessed in terms of force and displacement. The maximum stress on the implants in the experimental group was 247 MPa, with a maximum displacement at the fracture end of 0.200 mm. In contrast, the control group displayed a maximum stress on the implants of 434.9 MPa, coupled with a maximum displacement at the fracture end of 0.538 mm. These results demonstrated that the new intramedullary nail in the experimental group exhibited superior stress distribution and fracture fixation stability, with a smaller maximum displacement at the fracture end, despite the maximum stress occurring on the intramedullary nail. Subsequently, a three-point lateral bending experiment was conducted to further confirm the reliability of the internal fixation procedure. In this experiment, both ends of the tibia were immobilized, and a uniform 1000 N stress was applied to one side of the tibia. The results revealed that the maximum stress on the implants in the experimental group was 678.3 MPa, with a maximum displacement at the fracture end of 0.255 mm. In comparison, in the control group, the maximum stress on the implants was 413.7 MPa, and the maximum displacement at the fracture end was 0.826 mm. It is important to note that the stress performance of the experimental group, although not surpassing that of traditional intramedullary nails, remained within acceptable limits. The 678.3 MPa maximum stress, experienced during the 1000 N lateral bending test, was deemed acceptable since it represents an extreme stress condition, and the actual lateral bending stress endured by human tibial fractures after fixation is typically lower. Despite the new intramedullary nail exhibiting greater maximum stress and less maximum displacement, its fixation performance was superior. Under a rotational stress of 15 Nm, the experimental group displayed a maximum stress on the implants of 626.8 MPa, accompanied by a maximum displacement at the fracture end of 0.839 mm. In contrast, the control group exhibited a maximum stress on the implants of 289.1 MPa, along with a maximum displacement at the fracture end of 1.802 mm. Both models experienced stresses well within acceptable limits, without exceeding the ultimate bearing capacity of implants made from titanium alloy. In the experimental group, the new intramedullary nail achieved a decreased maximum displacement, indicating superior fracture fixation effectiveness. In this study, the finite element analysis method was used to simulate the middle tibial fracture model. However, in actual clinical work, the stress environment after internal fixation of tibial fractures is more complex and variable, and there are differences between individuals. Therefore, there are several limitations in this study, which need to be confirmed by further biomechanical studies and solid mechanics studies. Conclusion Our study suggested that the new intramedullary nail design system is a more favorable option for treating tibial fractures. Compared to the traditional intramedullary nail design system, the proposed approach yields superior fixation strength and stability and may be a novel approach for treating tibial fractures. Declarations Author contributions All of the authors were involved in the manuscript preparation. J Wu and ShH Qi conceived and designed the study. MM Pan and JC Huang analyzed and interpreted the data. HJ Xiao and J Wu drafted the manuscript and critically revised the manuscript for intellectual content. All authors read and approved the final manuscript. Funding This work was supported by Shanghai Health Commission of China under Grant No.20214Y0145. Availability of data and materials All data generated or analysed during this study are included in this article. Ethical approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors. This study conforms to the provisions of the Declaration of Helsinki and has been reviewed and approved by the Institutional Review Board of the Tinglin Hospital, Jinshan District, Shanghai. Consent for publication Not applicable. Competing interests There were no competing interests. Acknowledgements None. References Wani IH, Ul Gani N, Yaseen M, Bashir A, Bhat MS, Farooq M. Operative Management of Distal Tibial Extra-articular Fractures - Intramedullary Nail Versus Minimally Invasive Percutaneous Plate Osteosynthesis. Ortop Traumatol Rehabil. 2017 Dec 30;19(6):537-541. Costa ML, Achten J, Griffin J, Petrou S, Pallister I, Lamb SE, Parsons NR; FixDT Trial Investigators. Effect of Locking Plate Fixation vs Intramedullary Nail Fixation on 6-Month Disability Among Adults With Displaced Fracture of the Distal Tibia: The UK FixDT Randomized Clinical Trial. JAMA. 2017 Nov 14;318(18):1767-1776. Cheung G, Zalzal P, Bhandari M, Spelt JK, Papini M. 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Indian J Orthop. 2017 May-Jun;51(3):292-298. Bhat AK, Rao SK, Bhaskaranand K. Mechanical failure in intramedullary interlocking nails. J Orthop Surg (Hong Kong). 2006 Aug;14(2):138-41. Zelle BA, Bhandari M, Espiritu M, Koval KJ, Zlowodzki M; Evidence-Based Orthopaedic Trauma Working Group. Treatment of distal tibia fractures without articular involvement: a systematic review of 1125 fractures. J Orthop Trauma. 2006 Jan;20(1):76-9. Krettek C, Miclau T, Schandelmaier P, Stephan C, Möhlmann U, Tscherne H. The mechanical effect of blocking screws ("Poller screws") in stabilizing tibia fractures with short proximal or distal fragments after insertion of small-diameter intramedullary nails. J Orthop Trauma. 1999 Nov;13(8):550-3. Oh CW, Kyung HS, Park IH, Kim PT, Ihn JC. Distal tibia metaphyseal fractures treated by percutaneous plate osteosynthesis. Clin Orthop Relat Res. 2003 Mar;(408):286-91. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4377543","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":306102599,"identity":"3cc7a2ac-0e53-4d23-942a-d8537e5ac976","order_by":0,"name":"Jiang Wu","email":"","orcid":"","institution":"Tinglin Hospital of Jinshan District","correspondingAuthor":false,"prefix":"","firstName":"Jiang","middleName":"","lastName":"Wu","suffix":""},{"id":306102602,"identity":"5c4155b8-139a-4a54-bdda-594ad3df1d30","order_by":1,"name":"Mingmang Pan","email":"","orcid":"","institution":"Shanghai Jiaotong University, Shanghai Fengxian Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Mingmang","middleName":"","lastName":"Pan","suffix":""},{"id":306102607,"identity":"541b09fa-265d-4d48-8973-eb65bc4130ec","order_by":2,"name":"Junchao Huang","email":"","orcid":"","institution":"Tongji University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Junchao","middleName":"","lastName":"Huang","suffix":""},{"id":306102609,"identity":"fa2c6f93-548f-43cb-86bb-b449f3111db2","order_by":3,"name":"Haijun Xiao","email":"","orcid":"","institution":"Shanghai Jiaotong University, Shanghai Fengxian Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Haijun","middleName":"","lastName":"Xiao","suffix":""},{"id":306102616,"identity":"172d4ed1-73dd-4295-9476-7febf6344821","order_by":4,"name":"Shanhong Qi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAtUlEQVRIiWNgGAWjYDACZgY2IHlAjo29+QBpWoz5eI4lEG0PWEviPIkcBeLU8x1nf/bg54476W0MOQwMPyq2EdYieZjH3LD3zLPcNoazBxh7ztwmrMXgMA+bBG/b4dw2xr4EZsY2orSwP5P823Y4nY2Zx4BYLQxm0kBbEtjYiNUC9IuZtGzbYcM2HraEg0T5he/88WeSb9sOy8vPf3zwwY8KIrQwHMDBJlLLKBgFo2AUjAKsAADExDwAE2obmAAAAABJRU5ErkJggg==","orcid":"","institution":"Tinglin Hospital of Jinshan District","correspondingAuthor":true,"prefix":"","firstName":"Shanhong","middleName":"","lastName":"Qi","suffix":""}],"badges":[],"createdAt":"2024-05-06 14:32:55","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4377543/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4377543/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":57729631,"identity":"b5c44b00-1ec8-4112-8f49-132bfc46681e","added_by":"auto","created_at":"2024-06-04 21:53:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":483955,"visible":true,"origin":"","legend":"\u003cp\u003eIn contrast to that of the traditional intramedullary nail, the rod of the locking nail features an oval smooth structure, and the intramedullary nail's keyhole is also oval in shape. The locking nail is inserted into the intramedullary nail keyhole, establishing a secure lock between the locking hole and the locking nail. (1, intramedullary nail 2, keyhole 3, locking nail).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4377543/v1/7bc83d6a604a2488deda65b4.png"},{"id":57729623,"identity":"e3d8972d-d44e-4567-86d8-eac889c3947f","added_by":"auto","created_at":"2024-06-04 21:53:34","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":222830,"visible":true,"origin":"","legend":"\u003cp\u003eThe established tibial 3D model of experimental group (a) and control group (b). The experimental group utilized intramedullary nail designed with new locking nail while the control group used traditional intramedullary nail.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4377543/v1/fc42c7116a308a122cbd0f00.png"},{"id":57729630,"identity":"89ffe1ca-9351-4709-9af6-86faeea25eca","added_by":"auto","created_at":"2024-06-04 21:53:44","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1152577,"visible":true,"origin":"","legend":"\u003cp\u003eStress‒displacement distributions of the two groups of mid-tibial fracture models under axial 2500 N stress conditions.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4377543/v1/34649dad57589403ebb9ac97.png"},{"id":57729626,"identity":"5aa24e8e-c325-402f-8826-915ea4a0d95b","added_by":"auto","created_at":"2024-06-04 21:53:38","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1028706,"visible":true,"origin":"","legend":"\u003cp\u003eStress‒displacement distributions of the two groups of middle tibial fracture models under the 1000 N lateral bending stress condition.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4377543/v1/9c25659c71f8d5c0252d000b.png"},{"id":57729629,"identity":"7c87285d-64ce-4f01-9b96-38a9fa9f2ba8","added_by":"auto","created_at":"2024-06-04 21:53:42","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1026699,"visible":true,"origin":"","legend":"\u003cp\u003eStress‒displacement distributions of the middle tibial fracture models of the two groups under the rotational 15 Nm stress condition.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4377543/v1/a51add1a4d6003f0e65f7163.png"},{"id":75192950,"identity":"fa5a4b83-f5a4-45ab-bde9-1bfef7612aba","added_by":"auto","created_at":"2025-01-31 19:16:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4672756,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4377543/v1/e3c50f89-b66c-41bc-ac14-256e3d138e1b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Finite element analysis of intramedullary nails designed with new locking nail fixation for tibial fractures","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCurrently, common treatments for tibial fractures include internal fixation by locking plates and interlocking intramedullary nails. Interlocking intramedullary nail internal fixation offers advantages such as a reduced risk of local skin necrosis and exposure of the internal fixator due to minimal soft tissue manipulation. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] However, the distal end of the existing intramedullary nail suffers from low precision, leading to the adoption of a design featuring a gap between the keyhole and the locking nail to increase locking success rates. Unfortunately, this design compromises the stability of intramedullary nail fixation. [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] Our Orthopedics department has been dedicated to intramedullary nail research since 2010, resulting in the development of a novel fully locked interlocking intramedullary nail. This locking nail exhibited an oval smooth rod structure with an elliptical cross-section, while the intramedullary nail keyhole was also oval in shape. When the locking nail is inserted into the intramedullary nail keyhole, it becomes integrated through rotational locking, thereby improving fracture fixation stability (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). To improve the success of distal locking nails during surgical procedures, we devised specialized surgical targeting instruments that streamline the operation, facilitating precise distal locking. This study employed finite element analysis to validate the mechanical properties and compare the stiffness and stability of intramedullary nails designed with new locking mechanisms (experimental group) and with those of conventional intramedullary nails (control group) in tibial fracture fixation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eExperimental subjects\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA healthy adult female, 50 years of age, with a height of 170 cm and a weight of 65 kg, was selected from Tinglin Hospital, Jinshan District, Shanghai. Individuals with a history of bone diseases related to fractures, osteoporosis, pathological fractures, disuse atrophy, or other bone-related conditions were excluded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExperimental instruments and software\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e64-slice spiral CT (Siemens, Germany);\u003c/p\u003e\n\u003cp\u003eMimics 21.0 (The Materialise Group, Leuven, Belgium)\u003c/p\u003e\n\u003cp\u003e3-Matic Research 13.0 (The Materialise Group, Leuven, Belgium)\u003c/p\u003e\n\u003cp\u003eSolidWorks 2021 (DS Solidworks Corp, Waltham, MA, USA)\u003c/p\u003e\n\u003cp\u003eHypermesh 13.0 (Altai Engineering)\u003c/p\u003e\n\u003cp\u003eAbaqus 6.13 (Simulia Corp., Providence, RI, USA)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEstablishment of a 3D tibia model\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe entire tibia segment was subjected to scanning using a 64-slice spiral CT scanner to acquire two-dimensional transverse images. The resulting two-dimensional image data were saved in Dicom format, and the medical image processing software Mimics 21.0 was utilized. The data were imported into Mimics 21 software, and the tibia mask was constructed through three-dimensional reconstruction methods, including thresholding and multiple-slice editing. The generated model was saved in STL format for future reference.\u003c/p\u003e\n\u003cp\u003eA Handyscan307 3D scanner (Creaform, Canada) was used to perform 3D scans of intramedullary nails and screws, yielding point cloud data. The internal fixation 3D model was constructed using reverse engineering techniques and assembled in SolidWorks 2021. Subsequently, the internal fixation model was exported in iges format and meshed in Hypermesh 13.0 with a mesh size of 0.5 mm. The finalized internal fixation model was then exported in STL format.\u003c/p\u003e\n\u003cp\u003eThe STL models of the tibia and internal fixation were imported into 3-Matic Research 13.0 software for surgical planning. Initially, a 5 mm long fracture defect was created in the middle of the tibia to generate the tibia fracture model sample. Subsequently, with guidance from orthopedic surgeons, the internal fixator was positioned on the tibial model to simulate the procedure for internal fixation in tibial fractures. After the internal fixation was correctly placed, a Boolean operation was executed to obtain the postoperative tibial model. Following this, both the tibia model and the internal fixation model were brought into Hypermesh 13.0 for mesh optimization and the generation of solid meshes.\u003c/p\u003e\n\u003cp\u003eIn accordance with prior research[6], a mesh size of 1 mm was applied to the tibia, while a mesh size of 0.5 mm was used for internal fixation. After assessing the surface mesh quality within Hypermesh 13.0 (Altair Engineering), the model was divided into C3D4 solid units[1]. The solid cell model was subsequently exported to Abaqus 6.13 (Simulia Corp.) for further configuration of boundary conditions and finite element analysis. It was assumed that all the bone and implant models exhibited linear elastic properties. To assign material properties to each element, the apparent density (\u0026rho;), Young\u0026apos;s modulus (E), and Poisson\u0026apos;s ratio were determined based on the Hu values obtained from the CT scan. The following distinct formulas were applied for cortical bone and cancellous bone. The material properties of the bone were assigned using the grayscale method, with the assignment formula referring to previous research[7].\u003c/p\u003e\n\u003cp\u003e\u003cimg 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\" width=\"497\" height=\"212\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDigital production of tibial internal fixation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn line with the anatomical fracture model and the AO fracture fixation principles, a tibial intramedullary nail measuring 10*320 mm in size and length (provided by Dabo Company) was chosen, featuring distinct designs for the intramedullary nail keyhole. Creation of Locking Screws: Different screws were utilized for fixation, and various screw lengths were crafted to accommodate specific requirements.\u003c/p\u003e\n\u003cp\u003eAssembly of Components: Within the Creo software, the tibia model and tibia intramedullary screws were selected. Subsequently, the tibia and the components were assembled with intramedullary screws following the coordination instructions. As per the conventional surgical plan and clinical experience, three locking screws were employed for securing the proximal fracture, while two locking screws were used for fixing the distal fracture. Appropriate-length screws were employed in the assembly of the two distinct intramedullary nails for the tibia. This procedure resulted in an experimental group (comprising intramedullary nail with the new locking nail design) and a control group (comprising traditional intramedullary nail). (\u003cstrong\u003eFig.2\u003c/strong\u003e)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterial parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe material properties assigned to all intramedullary nails and locking nails were based on titanium (Ti-6 L-4 V), characterized by a Young\u0026apos;s modulus (E) of 110,000 MPa and a Poisson\u0026apos;s ratio of 0.3. [8-9]\u003c/p\u003e\n\u003cp\u003eTo simulate the mechanical nature of these implants, the interfaces between the new locking nail and intramedullary nail (experimental group) and between the screw and bone (control group) were tied, while the others were set to slide contact. The interfaces between the intramedullary nail and bone (experimental group and control group), locking nail and intramedullary nail (control group), and new locking nail and bone were set with a friction coefficient of 0.3. [10-11]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLoading loads and constraints\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn accordance with previous relevant literature, forces were applied to simulate the tibial platform conditions. Vertical force of 2500 N was applied with the lower tibial end fixed, with 60% distributed on the lateral side and 40% on the medial side. A load of 1500 N was applied to the medial tibia platform, along with 1000 N on the lateral tibia platform [12]. In the lateral bending experiment, both ends of the tibia were immobilized, and a uniform 1000 N force was applied to the tibia\u0026apos;s side [13]. For rotational force testing, the lower tibia was secured, and a 15 Nm clockwise torque was applied to the tibia platform [14]. Changes in the stress and displacement of the tibial fracture model were observed under these three force loading conditions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMain observation indicators\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study focused on two groups of patients utilizing different intramedullary nails for the fixation of middle tibial fractures. The key observation parameters included the maximum stress and displacement within the internal fixation and the maximum displacement at the fracture\u0026apos;s broken end. These parameters were evaluated and compared between the two groups.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eAxial load of 2500 N\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUnder an axial load of 2500 N, the maximum stress experienced by the specimens in the experimental group was 247.0 MPa, with a maximum displacement of the fractured end measuring 0.200 mm. In contrast, the control group exhibited a maximum stress of 434.9 MPa and a maximum displacement of broken ends measuring 0.538 mm.(\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eTable 1 and Fig.3)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e Maximum stress (MPa) and displacement (mm) of the middle tibial fracture model under the axial 2500 N stress condition\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"600\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.529215358931552%\" valign=\"top\" style=\"width: 11.9272%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.89649415692821%\" colspan=\"3\" valign=\"top\" style=\"width: 24.6914%;\"\u003e\n \u003cp\u003eExperimental group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.56427378964941%\" colspan=\"3\" valign=\"top\" style=\"width: 24.2729%;\"\u003e\n \u003cp\u003eControl group\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.072289156626507%\" valign=\"top\" style=\"width: 11.9272%;\"\u003e\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.122203098106713%\" valign=\"top\" style=\"width: 5.2312%;\"\u003e\n \u003cp\u003eBone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.27710843373494%\" valign=\"top\" style=\"width: 12.8688%;\"\u003e\n \u003cp\u003eIntramedullary nail\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.671256454388985%\" valign=\"top\" style=\"width: 6.4867%;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.122203098106713%\" valign=\"top\" style=\"width: 5.2312%;\"\u003e\n \u003cp\u003eBone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.27710843373494%\" valign=\"top\" style=\"width: 12.8688%;\"\u003e\n \u003cp\u003eIntramedullary nail\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.359724612736661%\" valign=\"top\" style=\"width: 6.1728%;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.529215358931552%\" valign=\"top\" style=\"width: 11.9272%;\"\u003e\n \u003cp\u003eStress\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.848080133555927%\" valign=\"bottom\" style=\"width: 5.2312%;\"\u003e\n \u003cp\u003e122.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.697829716193656%\" valign=\"bottom\" style=\"width: 12.8688%;\"\u003e\n \u003cp\u003e247.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.35058430717863%\" valign=\"bottom\" style=\"width: 6.4867%;\"\u003e\n \u003cp\u003e202.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.848080133555927%\" valign=\"bottom\" style=\"width: 5.2312%;\"\u003e\n \u003cp\u003e111.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.697829716193656%\" valign=\"bottom\" style=\"width: 12.8688%;\"\u003e\n \u003cp\u003e434.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.018363939899833%\" valign=\"bottom\" style=\"width: 6.1728%;\"\u003e\n \u003cp\u003e73.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.529215358931552%\" valign=\"top\" style=\"width: 11.9272%;\"\u003e\n \u003cp\u003eDisplacement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.848080133555927%\" valign=\"bottom\" style=\"width: 5.2312%;\"\u003e\n \u003cp\u003e3.607\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.697829716193656%\" valign=\"bottom\" style=\"width: 12.8688%;\"\u003e\n \u003cp\u003e3.305\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.35058430717863%\" valign=\"bottom\" style=\"width: 6.4867%;\"\u003e\n \u003cp\u003e3.412\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.848080133555927%\" valign=\"bottom\" style=\"width: 5.2312%;\"\u003e\n \u003cp\u003e3.861\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.697829716193656%\" valign=\"bottom\" style=\"width: 12.8688%;\"\u003e\n \u003cp\u003e3.300\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.018363939899833%\" valign=\"bottom\" style=\"width: 6.1728%;\"\u003e\n \u003cp\u003e3.682\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.529215358931552%\" valign=\"top\" style=\"width: 11.9272%;\"\u003e\n \u003cp\u003eDisplacement of broken end\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.89649415692821%\" colspan=\"3\" valign=\"bottom\" style=\"width: 24.6914%;\"\u003e\n \u003cp\u003e0.200\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.56427378964941%\" colspan=\"3\" valign=\"bottom\" style=\"width: 24.2729%;\"\u003e\n \u003cp\u003e0.538\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLateral bending stress of 1000 N\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUnder a lateral bending stress of 1000 N, the experimental group exhibited a maximum stress of 678.3 MPa, with a maximum displacement at the fracture end of 0.255 mm. In contrast, the control group displayed a maximum stress of 413.7 MPa, accompanied by a maximum displacement at the fracture end of 0.826 mm. (\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eTable 2 and Fig. 4)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e Maximum stress (MPa) and displacement (mm) of the middle tibial fracture model under a lateral bending stress condition of 1000 N\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"620\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.774193548387096%\" valign=\"top\" style=\"width: 10.8124%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.03225806451613%\" colspan=\"3\" valign=\"top\" style=\"width: 25.2627%;\"\u003e\n \u003cp\u003eExperimental group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"40.806451612903224%\" colspan=\"3\" valign=\"top\" style=\"width: 24.2522%;\"\u003e\n \u003cp\u003eControl group\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.362270450751254%\" valign=\"top\" style=\"width: 10.8124%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.348914858096828%\" valign=\"top\" style=\"width: 5.861%;\"\u003e\n \u003cp\u003eBone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.20033388981636%\" valign=\"top\" style=\"width: 12.6314%;\"\u003e\n \u003cp\u003eIntramedullary nail\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.851419031719532%\" valign=\"top\" style=\"width: 6.7704%;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.515859766277128%\" valign=\"top\" style=\"width: 5.962%;\"\u003e\n \u003cp\u003eBone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.20033388981636%\" valign=\"top\" style=\"width: 12.6314%;\"\u003e\n \u003cp\u003eIntramedullary nail\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.520868113522537%\" valign=\"top\" style=\"width: 5.7599%;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.774193548387096%\" valign=\"top\" style=\"width: 10.8124%;\"\u003e\n \u003cp\u003eStress\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.03225806451613%\" valign=\"bottom\" style=\"width: 5.861%;\"\u003e\n \u003cp\u003e160.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.516129032258064%\" valign=\"bottom\" style=\"width: 12.6314%;\"\u003e\n \u003cp\u003e454.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.483870967741936%\" valign=\"bottom\" style=\"width: 6.7704%;\"\u003e\n \u003cp\u003e678.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.193548387096774%\" valign=\"bottom\" style=\"width: 5.962%;\"\u003e\n \u003cp\u003e310.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.516129032258064%\" valign=\"bottom\" style=\"width: 12.6314%;\"\u003e\n \u003cp\u003e413.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.096774193548388%\" valign=\"bottom\" style=\"width: 5.7599%;\"\u003e\n \u003cp\u003e249.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.774193548387096%\" valign=\"top\" style=\"width: 10.8124%;\"\u003e\n \u003cp\u003eDisplacement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.03225806451613%\" valign=\"bottom\" style=\"width: 5.861%;\"\u003e\n \u003cp\u003e8.610\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.516129032258064%\" valign=\"bottom\" style=\"width: 12.6314%;\"\u003e\n \u003cp\u003e8.500\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.483870967741936%\" valign=\"bottom\" style=\"width: 6.7704%;\"\u003e\n \u003cp\u003e8.387\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.193548387096774%\" valign=\"bottom\" style=\"width: 5.962%;\"\u003e\n \u003cp\u003e9.485\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.516129032258064%\" valign=\"bottom\" style=\"width: 12.6314%;\"\u003e\n \u003cp\u003e9.267\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.096774193548388%\" valign=\"bottom\" style=\"width: 5.7599%;\"\u003e\n \u003cp\u003e9.499\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.774193548387096%\" valign=\"top\" style=\"width: 10.8124%;\"\u003e\n \u003cp\u003eDisplacement of broken end\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.03225806451613%\" colspan=\"3\" valign=\"top\" style=\"width: 25.2627%;\"\u003e\n \u003cp\u003e0.255\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"40.806451612903224%\" colspan=\"3\" valign=\"top\" style=\"width: 24.2522%;\"\u003e\n \u003cp\u003e0.826\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eRotational stress of 15 Nm\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUnder a rotational stress of 15 Nm, the experimental group exhibited a maximum stress of 626.8 MPa, with a maximum displacement at the fracture end of 0.839 mm. In contrast, the control group displayed a maximum stress of 289.1 MPa, accompanied by a maximum displacement at the fracture end of 1.802 mm. (\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eTable 3 and Fig. 5)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e Maximum stress (MPa) and displacement (mm) of the middle tibial fracture model under the rotational 15 Nm stress condition\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"615\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.910569105691057%\" valign=\"top\" style=\"width: 9.9424%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.886178861788615%\" colspan=\"3\" valign=\"top\" style=\"width: 22.1148%;\"\u003e\n \u003cp\u003eExperimental group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"41.951219512195124%\" colspan=\"4\" valign=\"top\" style=\"width: 23.137%;\"\u003e\n \u003cp\u003eControl group\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.50841750841751%\" valign=\"top\" style=\"width: 9.9424%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.090909090909092%\" valign=\"top\" style=\"width: 5.1106%;\"\u003e\n \u003cp\u003eBone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.52861952861953%\" valign=\"top\" style=\"width: 11.0574%;\"\u003e\n \u003cp\u003eIntramedullary nail\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.606060606060606%\" valign=\"top\" style=\"width: 5.9469%;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.090909090909092%\" valign=\"top\" style=\"width: 5.1106%;\"\u003e\n \u003cp\u003eBone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.52861952861953%\" valign=\"top\" style=\"width: 11.0574%;\"\u003e\n \u003cp\u003eIntramedullary nail\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.646464646464647%\" colspan=\"2\" valign=\"top\" style=\"width: 6.969%;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.938110749185668%\" valign=\"top\" style=\"width: 9.9424%;\"\u003e\n \u003cp\u003eStress\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.794788273615636%\" valign=\"top\" style=\"width: 5.1106%;\"\u003e\n \u003cp\u003e168.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.892508143322477%\" valign=\"top\" style=\"width: 11.0574%;\"\u003e\n \u003cp\u003e626.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.260586319218241%\" valign=\"top\" style=\"width: 5.9469%;\"\u003e\n \u003cp\u003e515.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.794788273615636%\" valign=\"top\" style=\"width: 5.1106%;\"\u003e\n \u003cp\u003e355.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.892508143322477%\" valign=\"top\" style=\"width: 11.0574%;\"\u003e\n \u003cp\u003e264.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.169381107491857%\" colspan=\"2\" valign=\"top\" style=\"width: 6.969%;\"\u003e\n \u003cp\u003e289.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.938110749185668%\" valign=\"top\" style=\"width: 9.9424%;\"\u003e\n \u003cp\u003eDisplacement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.794788273615636%\" valign=\"top\" style=\"width: 5.1106%;\"\u003e\n \u003cp\u003e3.349\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.892508143322477%\" valign=\"top\" style=\"width: 11.0574%;\"\u003e\n \u003cp\u003e1.831\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.260586319218241%\" valign=\"top\" style=\"width: 5.9469%;\"\u003e\n \u003cp\u003e3.323\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.794788273615636%\" valign=\"top\" style=\"width: 5.1106%;\"\u003e\n \u003cp\u003e5.983\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.892508143322477%\" valign=\"top\" style=\"width: 11.0574%;\"\u003e\n \u003cp\u003e2.778\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.169381107491857%\" colspan=\"2\" valign=\"top\" style=\"width: 6.969%;\"\u003e\n \u003cp\u003e5.935\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.910569105691057%\" valign=\"top\" style=\"width: 9.9424%;\"\u003e\n \u003cp\u003eDisplacement of broken end\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.886178861788615%\" colspan=\"3\" valign=\"top\" style=\"width: 22.1148%;\"\u003e\n \u003cp\u003e0.839\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"41.78861788617886%\" colspan=\"3\" valign=\"top\" style=\"width: 22.5794%;\"\u003e\n \u003cp\u003e1.802\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.16260162601626016%\" style=\"width: 0.6504%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eTibial fractures often result from severe direct injuries. In the past, treatments such as plaster fixation, traditional open reduction with plate internal fixation, and external fixation with stent fixation frequently led to complications, including ankle joint stiffness, local infections, wound necrosis, nail tract infections, delayed fracture healing, and deformities. These approaches often yield unsatisfactory results[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Currently, minimally invasive percutaneous plate osteoplasty (MIPPO) is a widely employed surgical technique in the clinical management of such fractures. MIPPO helps reduce the extent of soft tissue damage to some extent[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, not all tibial fractures are suitable for plating, especially those involving severe soft tissue damage and poor skin conditions. Plate implantation may carry risks of skin irritation, incision infections, local skin necrosis, and plate exposure, among other complications[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Furthermore, the process of plate internal fixation typically involves the removal of additional soft tissue, which disrupts blood flow around the fracture site and can adversely affect fracture healing[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIntramedullary nailing represents another effective method for stabilizing distal tibial fractures. Numerous studies have demonstrated that the use of intramedullary nails aligns with the prevailing trend of minimally invasive treatment and the concept of biological osteosynthesis (BO). This approach results in reduced local soft tissue trauma and fewer postoperative complications, such as soft tissue necrosis and osteomyelitis, garnering increased attention in its application. In fact, the surgical indications for interlocking intramedullary nails have expanded to encompass some distal tibial fractures. Nevertheless, the clinical utilization of interlocking intramedullary nail technology has faced scrutiny, primarily concerning its ability to effectively maintain fracture stability. The key point of contention lies in the accuracy of locking achieved by existing distal intramedullary nail technology. Currently, there is a certain gap between the keyhole and the locking rod (typically approximately 0.3\u0026ndash;0.5 mm), impacting interlocking intramedullary nail fixation. While this gap-fitting approach between the keyhole and the locking nail enhances the locking nail's success rate, it diminishes fixation stability. The resulting interaction between the locking nail and the intramedullary nail yields relatively stable fixation, but this approach does not strictly adhere to the concept of BO. For distal tibial fractures located within 5 cm of the ankle surface, the interlocking effect is further compromised due to the limited working distance of the distal end of the intramedullary nail. In particular, the large size of the distal tibial medullary cavity, strong muscle tension, relatively slender intramedullary nails, and possibility of slippage between the intramedullary nail and the locking nail can lead to suboptimal control of fracture angles and an increased risk of coronal angle displacement. Therefore, despite the mechanical advantages associated with intramedullary nailing, its clinical effectiveness in managing distal tibial fractures remains a subject of debate[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo enhance the stability of intramedullary nailing in the treatment of tibial fractures, Krettek introduced the Poller nailing technique in 1999[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. This technique involves the placement of 1\u0026ndash;2 blocking screws in close proximity to the intramedullary nail to prevent wobbling within the medullary canal. In recent years, as intramedullary nail design has continued to advance, the utilization of specialized intramedullary nails for distal tibial fractures has gained popularity. These nails feature a flat distal end with the keyhole positioned just 5 mm from the nail tip. This design shortens the gap between the keyhole and the nail tip, enabling multiplanar locking. These advancements expand surgical indications, increase fracture fixation stability, and effectively address fractures within 5 cm of the ankle joint surface. To enhance stability, additional measures such as fibula internal fixation and cast external fixation may be needed. While these approaches improve the stability of tibial fracture fixation to some extent, they also increase surgical trauma. Nevertheless, further improvements are needed to enhance the stability of the internal fixation[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn response to the aforementioned factors, our hospital's Orthopedics Department introduced a newly designed locking intramedullary nail fixation system and developed a corresponding aiming and fine-tuning device. The locking nail featured an elliptical smooth rod structure with an elliptical cross-section, and the keyhole of the intramedullary nail was similarly designed to be oval. When the locking nail was inserted into the keyhole, a rotational locking mechanism integrated the locking screw with the intramedullary nail, thereby enhancing fracture fixation stability. To improve the success rate of distal locking nail placement during surgery, specialized surgical targeting instruments were used to streamline the procedure and ensure precise distal locking.\u003c/p\u003e \u003cp\u003eIn this study, a middle tibial fracture model was created using the finite element method, simulating tibial fracture fixation with two types of implants in the experimental group (new intramedullary nail) and the control group (traditional intramedullary nail). First, under an axial load of 2500 N, akin to the forces experienced during strenuous activities such as running and jumping, the performance of both experimental models was assessed in terms of force and displacement. The maximum stress on the implants in the experimental group was 247 MPa, with a maximum displacement at the fracture end of 0.200 mm. In contrast, the control group displayed a maximum stress on the implants of 434.9 MPa, coupled with a maximum displacement at the fracture end of 0.538 mm. These results demonstrated that the new intramedullary nail in the experimental group exhibited superior stress distribution and fracture fixation stability, with a smaller maximum displacement at the fracture end, despite the maximum stress occurring on the intramedullary nail. Subsequently, a three-point lateral bending experiment was conducted to further confirm the reliability of the internal fixation procedure. In this experiment, both ends of the tibia were immobilized, and a uniform 1000 N stress was applied to one side of the tibia. The results revealed that the maximum stress on the implants in the experimental group was 678.3 MPa, with a maximum displacement at the fracture end of 0.255 mm. In comparison, in the control group, the maximum stress on the implants was 413.7 MPa, and the maximum displacement at the fracture end was 0.826 mm. It is important to note that the stress performance of the experimental group, although not surpassing that of traditional intramedullary nails, remained within acceptable limits. The 678.3 MPa maximum stress, experienced during the 1000 N lateral bending test, was deemed acceptable since it represents an extreme stress condition, and the actual lateral bending stress endured by human tibial fractures after fixation is typically lower. Despite the new intramedullary nail exhibiting greater maximum stress and less maximum displacement, its fixation performance was superior. Under a rotational stress of 15 Nm, the experimental group displayed a maximum stress on the implants of 626.8 MPa, accompanied by a maximum displacement at the fracture end of 0.839 mm. In contrast, the control group exhibited a maximum stress on the implants of 289.1 MPa, along with a maximum displacement at the fracture end of 1.802 mm. Both models experienced stresses well within acceptable limits, without exceeding the ultimate bearing capacity of implants made from titanium alloy. In the experimental group, the new intramedullary nail achieved a decreased maximum displacement, indicating superior fracture fixation effectiveness.\u003c/p\u003e \u003cp\u003eIn this study, the finite element analysis method was used to simulate the middle tibial fracture model. However, in actual clinical work, the stress environment after internal fixation of tibial fractures is more complex and variable, and there are differences between individuals. Therefore, there are several limitations in this study, which need to be confirmed by further biomechanical studies and solid mechanics studies.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOur study suggested that the new intramedullary nail design system is a more favorable option for treating tibial fractures. Compared to the traditional intramedullary nail design system, the proposed approach yields superior fixation strength and stability and may be a novel approach for treating tibial fractures.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll of the authors were involved in the manuscript preparation. J Wu and ShH Qi conceived and designed the study. MM Pan and JC Huang analyzed and interpreted the data. HJ Xiao and J Wu drafted the manuscript and critically revised the manuscript for intellectual content. All authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Shanghai Health Commission of China under Grant No.20214Y0145.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this article.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis article does not contain any studies with human participants or animals performed by any of the authors. This study conforms to the provisions of the Declaration of Helsinki and has been reviewed and approved by the Institutional Review Board of the Tinglin Hospital, Jinshan District, Shanghai.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere were no competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWani IH, Ul Gani N, Yaseen M, Bashir A, Bhat MS, Farooq M. Operative Management of Distal Tibial Extra-articular Fractures - Intramedullary Nail Versus Minimally Invasive Percutaneous Plate Osteosynthesis. Ortop Traumatol Rehabil. 2017 Dec 30;19(6):537-541.\u003c/li\u003e\n\u003cli\u003eCosta ML, Achten J, Griffin J, Petrou S, Pallister I, Lamb SE, Parsons NR; FixDT Trial Investigators. Effect of Locking Plate Fixation vs Intramedullary Nail Fixation on 6-Month Disability Among Adults With Displaced Fracture of the Distal Tibia: The UK FixDT Randomized Clinical Trial. JAMA. 2017 Nov 14;318(18):1767-1776.\u003c/li\u003e\n\u003cli\u003eCheung G, Zalzal P, Bhandari M, Spelt JK, Papini M. Finite element analysis of a femoral retrograde intramedullary nail subject to gait loading. Med Eng Phys. 2004 Mar;26(2):93-108. \u003c/li\u003e\n\u003cli\u003eAntekeier SB, Burden RL Jr, Voor MJ, Roberts CS. Mechanical study of the safe distance between distal femoral fracture site and distal locking screws in antegrade intramedullary nailing. J Orthop Trauma. 2005 Nov-Dec;19(10):693-7. \u003c/li\u003e\n\u003cli\u003eShih KS, Tseng CS, Lee CC, Lin SC. Influence of muscular contractions on the stress analysis of distal femoral interlocking nailing. Clin Biomech (Bristol, Avon). 2008 Jan;23(1):38-44.\u003c/li\u003e\n\u003cli\u003eJiang D, Zhan S, Cai Q, Hu H, Jia W. Enhanced interfragmentary stability and improved clinical prognosis with use of the off-axis screw technique to treat vertical femoral neck fractures in nongeriatric patients. J Orthop Surg Res. 2021 Jul 31;16(1):473.\u003c/li\u003e\n\u003cli\u003eReina-Romo E, Rodr\u0026iacute;guez-Vall\u0026eacute;s J, Sanz-Herrera JA. In silico dynamic characterization of the femur: Physiological versus mechanical boundary conditions. Med Eng Phys. 2018 Jun 23:S1350-4533(18)30090-0. \u003c/li\u003e\n\u003cli\u003eFan Y, Xiu K, Duan H, Zhang M. Biomechanical and histological evaluation of the application of biodegradable poly-L-lactic cushion to the plate internal fixation for bone fracture healing. Clin Biomech (Bristol, Avon). 2008;23 Suppl 1:S7-S16.\u003c/li\u003e\n\u003cli\u003eBenli S, Aksoy S, Havitcioğlu H, Kucuk M. Evaluation of bone plate with low-stiffness material in terms of stress distribution. J Biomech. 2008 Nov 14;41(15):3229-35.\u003c/li\u003e\n\u003cli\u003eChen P, Lu H, Shen H, Wang W, Ni B, Chen J. Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study. J Orthop Surg Res. 2017 Feb 23;12(1):35. \u003c/li\u003e\n\u003cli\u003eHuang X, Zhi Z, Yu B, Chen F. Stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture: a comparative finite element study. J Orthop Surg Res. 2015 Nov 25;10:182. \u003c/li\u003e\n\u003cli\u003eLuo CA, Hwa SY, Lin SC, Chen CM, Tseng CS. Placement-induced effects on high tibial osteotomized construct - biomechanical tests and finite-element analyses. BMC Musculoskelet Disord. 2015 Sep 4;16:235. \u003c/li\u003e\n\u003cli\u003eLi J, Zhao X, Hu X, Tao C, Ji R. A theoretical analysis and finite element simulation of fixator-bone system stiffness on healing progression. J Appl Biomater Funct Mater. 2018 Jul;16(3):115-125. \u003c/li\u003e\n\u003cli\u003eSonoda N, Chosa E, Totoribe K, Tajima N. Biomechanical analysis for stress fractures of the anterior middle third of the tibia in athletes: nonlinear analysis using a three-dimensional finite element method. J Orthop Sci. 2003;8(4):505-13. \u003c/li\u003e\n\u003cli\u003eG\u0026uuml;labi D, Bekler Hİ, Sağlam F, Taşdemir Z, \u0026Ccedil;e\u0026ccedil;en GS, Elmalı N. Surgical treatment of distal tibia fractures: open versus MIPO. Ulus Travma Acil Cerrahi Derg. 2016 Jan;22(1):52-7. \u003c/li\u003e\n\u003cli\u003eDaolagupu AK, Mudgal A, Agarwala V, Dutta KK. A comparative study of intramedullary interlocking nailing and minimally invasive plate osteosynthesis in extra articular distal tibial fractures. Indian J Orthop. 2017 May-Jun;51(3):292-298. \u003c/li\u003e\n\u003cli\u003eBhat AK, Rao SK, Bhaskaranand K. Mechanical failure in intramedullary interlocking nails. J Orthop Surg (Hong Kong). 2006 Aug;14(2):138-41.\u003c/li\u003e\n\u003cli\u003eZelle BA, Bhandari M, Espiritu M, Koval KJ, Zlowodzki M; Evidence-Based Orthopaedic Trauma Working Group. Treatment of distal tibia fractures without articular involvement: a systematic review of 1125 fractures. J Orthop Trauma. 2006 Jan;20(1):76-9. \u003c/li\u003e\n\u003cli\u003eKrettek C, Miclau T, Schandelmaier P, Stephan C, M\u0026ouml;hlmann U, Tscherne H. The mechanical effect of blocking screws (\u0026quot;Poller screws\u0026quot;) in stabilizing tibia fractures with short proximal or distal fragments after insertion of small-diameter intramedullary nails. J Orthop Trauma. 1999 Nov;13(8):550-3.\u003c/li\u003e\n\u003cli\u003eOh CW, Kyung HS, Park IH, Kim PT, Ihn JC. Distal tibia metaphyseal fractures treated by percutaneous plate osteosynthesis. Clin Orthop Relat Res. 2003 Mar;(408):286-91.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Tibial fracture, Finite element analysis, Tibial intramedullary nai","lastPublishedDoi":"10.21203/rs.3.rs-4377543/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4377543/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective:\u003c/strong\u003e The potential instability of tibial fracture fixation with intramedullary nails due to gap coordination between locking nails and holes was investigated. The aim of this study was to explore a more stable and reliable internal fixation method using intramedullary nails designed with new locking mechanisms.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e Tibial CT image data from a healthy female were obtained to create a tibial fracture model in the middle section using finite element digital technology. Subsequently, two different intramedullary nails were utilized for fixation. The experimental group employed intramedullary nails designed with new locking mechanisms, while the control group used conventional intramedullary nails. The specimens were subjected to axial loading of 2500 N, lateral bending of 1000 N, and rotational forces of 15 Nm. The maximum stress and displacement of the bone and internal fixation were recorded for both groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Under an axial stress of 2500 N, the maximum stress on the internal fixation in the experimental group was 247.0 MPa, with the maximum displacement of the fracture end reaching 0.200 mm. In the control group, the maximum stress on the internal fixation was 434.9 MPa, and the maximum displacement of the fracture ends was 0.538 mm. For a lateral bending stress of 1000 N, the maximum stress on the internal fixation in the experimental group was 678.0 MPa, and the maximum displacement of the fracture end was 0.255 mm. In the control group, the maximum stress on the internal fixation was 413.7 MPa, and the maximum displacement of the fracture end was 0.826 mm. When subjected to a rotational stress of 15 Nm, the maximum stress on the internal fixation in the experimental group was 626.8 MPa, with the maximum displacement of the fracture end measuring 0.839 mm. In contrast, the control group exhibited a maximum stress of 289.1 MPa on the internal fixation, along with a maximum displacement of the fracture end of 1.802 mm.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eCompared with traditional intramedullary nail designs, the new intramedullary nail design provides superior mechanical support for middle tibial fractures and offers more biomechanical advantages.\u003c/p\u003e","manuscriptTitle":"Finite element analysis of intramedullary nails designed with new locking nail fixation for tibial fractures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-04 21:53:22","doi":"10.21203/rs.3.rs-4377543/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a7159185-28b2-4186-9531-546f9096e286","owner":[],"postedDate":"June 4th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-31T19:08:27+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-04 21:53:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4377543","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4377543","identity":"rs-4377543","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}