Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C Fractures

Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C 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 Article Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C Fractures huo xie, Yixuan Cao, Ke Sun This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8612025/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Objective , To analyze the biomechanical performance differences between the Force-Multiplying Bridge structural screw fixation system (a screw arrangement configuration derived from truss elements) and the traditional plate-screw fixation system in the treatment of distal radius type C fractures using finite element analysis. Methods , Three-dimensional models of distal radius type C fractures were constructed from radial CT image data using Mimics, Geomagic Wrap, and SolidWorks software. Two groups were established: the plate-screw group and the Force-Multiplying Bridge group. In the Force-Multiplying Bridge group, 6 screws were used to construct a triangular truss support system. Finite element analysis was performed using ANSYS software. Results , Under the axial loading condition, the plate-screw group is slightly superior to the Force-Multiplying Bridge group. Under the rotational working condition, the maximum displacement of the Force-Multiplying Bridge group was significantly better than that of the plate-screw group, showing superior anti-torsion performance. Under the palmar flexion/dorsal extension working conditions, the displacement of the plate-screw group was smaller than that of the Force-Multiplying Bridge group. The articular surfaces of the plate-screw group showed a cracked pattern under axial, palmar flexion, and dorsal extension working conditions, while no obvious separation of the articular surfaces was observed in the Force-Multiplying Bridge group under all working conditions. Conclusion , The Force-Multiplying Bridge structural screw fixation system not only achieves performance comparable to that of the traditional plate-screw system but also exhibits significant advantages in terms of articular surface fixation. Physical sciences/Engineering Physical sciences/Materials science Distal Radius Type C Fracture Finite Element Analysis Force-Multiplying Bridge Structure Truss Element Internal Fixation System Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction The Force-Multiplying Bridge is an innovative configuration designed based on mechanical optimization. Its core comprises assemblable truss units, high-strength connectors, and load-bearing panels, and it relies on the geometric stability of triangles to establish a force transmission system [1] . A key feature of this structure lies in its ability to achieve load distribution through rational structural layout: it transmits external forces evenly to each stress-bearing component, while leveraging the mechanical amplification effect to significantly enhance overall load-bearing capacity with a relatively small amount of materials. In the field of engineering, this structure has been widely applied in scenarios such as wartime bridge construction and emergency access establishment for disaster relief, thanks to its advantages of convenient assembly and adjustable span, demonstrating excellent mechanical stability and adaptability.​ In the AO classification of distal radius fractures, Type C fractures are intra-articular fractures, which generally require open reduction and internal fixation (ORIF) in clinical practice. Traditional plate-screw internal fixation often suffers from uneven mechanical distribution of the fixation structure, leading to local stress concentration [2] . This issue is prone to causing complications such as fixation loosening, screw breakage, and delayed fracture healing. The introduction of the force-multiplying bridge structure into fracture screw internal fixation can effectively alleviate local stress concentration through its load dispersion and stress optimization characteristics. It enhances the overall stability of the fixation system via a mechanical amplification effect [3] , providing a mechanical environment for the fracture site that better meets physiological needs. Meanwhile, it reduces the risk of fatigue failure of internal fixation devices, offering a new fixation scheme for the treatment of Type C distal radius fractures. If implemented, this scheme can provide a more minimally invasive treatment approach compared to traditional plate-screw fixation, creating a more favorable recovery environment for patients' postoperative rehabilitation. Materials/Subjects and Methods 1.1 Design: A C-type fracture model (intra-articular four-part fracture) was constructed based on the distal radius fracture model. The articular surface was used as the bridge deck, and a force-multiplying bridge structure was built with 6 screws, as shown in Figure 1 c1. The state after the 6 screws were inserted into the distal radius is shown in Figure 1 c. 1.2 Time and Location: The experiment was conducted at the Fourth People's Hospital of Longgang District, Shenzhen from June to August 2025. 1.3 Materials/Subjects One 40-year-old healthy female volunteer was selected, with a height of 160 cm, no previous forearm trauma or other diseases. The volunteer's distal radius CT data were acquired and saved in DICOM format. This study was approved by the Medical Ethics Committee of the Fourth People's Hospital of Longgang District, Shenzhen, with the approval number: 202307. The volunteer signed the informed consent form and voluntarily agreed to participate in this study. The experiment strictly adhered to the principles and norms formulated by the Medical Ethics Committee of the hospital. 1.4 Methods 1.4.1 Establishment of the Distal Radius Type C Fracture Model A thin-slice CT scan was performed layer by layer on the volunteer's intact forearm to acquire complete DICOM data of the radius. Subsequently, Mimics 21.0 software was used to import the radius DICOM data. Appropriate grayscale values were set for the data, followed by operations including threshold segmentation, region growing, and mask editing to fill gaps. Then, region growing was conducted again to isolate the radius individually and fill voids within it. The segmented mask was used to generate a 3D model; after confirming that all osseous landmarks of the radius were intact, the model was smoothed and exported in STP format. The STP format model was imported into Geomagic Wrap 2017 software. Operations such as 3D surface patch subdivision, noise reduction, feature removal, grid construction, and surface fitting were performed to establish a solid model of the radial cortical bone. An offset operation was applied to this cortical bone model to obtain a solid model of the cancellous bone, which was then saved separately in STP format. Further, the established models were imported into SolidWorks 2021. The cortical bone and cancellous bone models were assembled using the origin mating command and saved in a part file format. According to the AO fracture classification, the model was processed to create a fracture model, as shown in Figure 1 a below. 1.4.2 Grouped Assembly In this experiment, a steel plate-screw group and a force-multiplying bridge group were set up for comparative analysis. The steel plates were provided by Xiamen Dabo Medical Technology Co., Ltd., and both groups used 2.7 mm-sized screws. Among them, the assembled steel plate-screw group is shown in Figure 1 b, and the steel plate and screws are shown in Figure 1 b1; the assembled force-multiplying bridge group is shown in Figure 1 c. For the construction of the force-multiplying bridge screws, the articular surface was used as the bridge deck, and the ulnar and radial sides served as the two ends of the "bank". Screws of the same specification as those in the steel plate-screw group were used for construction (as shown in Figure 1 c1), with a total of 6 screws employed. The assembled assemblies of the two groups, completed using SolidWorks 2021, are shown in Figure 1 b and Figure 1 c respectively. The assemblies were saved separately as XT files. 1.5 Finite Element Analysis 1.5.1 Material Assignment and Mesh Generation The two groups of models mentioned above were imported into the finite element analysis software ANSYS 17.0 respectively, and a static analysis module was created. The elastic moduli and Poisson's ratios of cortical bone, cancellous bone, steel plates, and screws are listed in Table 1. Contact Settings: A frictional contact with a friction coefficient of 0.4 was adopted between the steel plate-screw and the bone, while a bonded contact was used between the screws and the steel plate. Tetrahedral elements were used for mesh generation of the models, with a mesh size of 1 mm. The number of nodes and meshes for each group of models are shown in Table 2. Table 1 Material Parameters of the Model Material Elastic Modulus (MPa) Poisson's Ratio Cortical Bone 17 000 0.3 Cancellous Bone 13 000 0.33 Plate 110 000 0.35 Screws 109 000 0.33 Table 2 Number of Nodes and Elements of the Two Groups of Models After Mesh Generation Model Number of Nodes Number of Elements Plate-Screw Group 589191 318573 Force-Multiplying Bridge Group 367362 201202 1.5.2 Loading Conditions and Boundary Conditions In this study, simulation tests of loads in four directions were conducted on the two groups of models, namely axial, dorsal extension, palmar flexion, and rotation. The loading conditions were determined based on references: For the axial movement of the radius: A 20 N axial load was applied to the distal radial articular surface (Loading Condition 1); For the rotational movement of the radius: A 1 N·m torsional load was applied to the distal radial articular surface (Loading Condition 2); For the palmar flexion movement of the radius: A 5 N load in the palmar direction was applied to the dorsal part of the distal radial bone surface (Loading Condition 3); For the dorsal extension movement of the radius: A 5 N load in the radial dorsal extension direction was applied to a selected part of the palmar surface of the distal radius (Loading Condition 4). The bone surface near the proximal radius was fully constrained to simulate the fixed state of the proximal radius. 1.6 Main Outcome Measures After applying the four types of loads in different directions to the two groups of models, the following indicators were observed respectively: ① Displacement distribution and maximum displacement of the internal fixation model; ② Stress distribution and maximum stress of the internal fixation device; ③ Stress distribution and maximum stress of the articular surface. Results 2.1 Maximum Displacement and Distribution of the Internal Fixation Model The force-multiplying bridge group outperformed the steel plate-screw group under the rotational load case (Figure 2 a2-b2), and the two groups showed similar performance under the axial load case (Figure 2 a1-b1). However, the steel plate-screw group exhibited better deformation control under the palmar flexion and dorsiflexion load cases (Figure 2 a3-b3, a4-b5). The force-multiplying bridge group had slightly greater deformation under the palmar flexion and dorsiflexion load cases, but there was no significant difference in the internal comparison of the force-multiplying bridge group under these two load cases (Figure 2 b3-b4). In contrast, the steel plate-screw group showed a significant difference in the internal comparison under the palmar flexion and dorsiflexion load cases (Figure 2 a3-a4), which is attributed to the lack of dorsal support of the volar plate when force is applied in the dorsiflexion direction. Overall, the two groups had roughly comparable biomechanical performance in terms of total deformation, and both could provide effective fixation for the distal radius. The maximum displacement results from Figure 2, grouped by group and load case, are listed in Table 3 below. Table 3 Displacement of the Two Groups Under Four Load Cases Grouping Axial Rotational Palmar Dorsal Plate-Screw Group 0.16356mm 0.65981mm 0.37695mm 0.09147mm Force-Multiplying Bridge Group 0.24323mm 0.23078mm 0.60467mm 0.60411mm Axial Load Case Steel Plate-Screw Group (Figure 2 a1): Maximum deformation was approximately 0.16356 mm; Force-Multiplying Bridge Group (Figure 2 b1): Maximum deformation was approximately 0.24323 mm. Analysis: The axial load simulates the weight-bearing pressure of the limb. The deformation of both groups was within a small magnitude range. The force-multiplying bridge group had slightly greater deformation, but the numerical difference was not significant. From the perspective of biomechanical stability, both groups could provide effective axial support for the radius, with the steel plate-screw group having a slight advantage in deformation performance. Rotational Load Case Steel Plate-Screw Group (Figure 2 a2): Maximum deformation was approximately 0.65981 mm; Force-Multiplying Bridge Group (Figure 2 b2): Maximum deformation was approximately 0.23078 mm. Analysis: The rotational load simulates the torsional movement of the limb. The force-multiplying bridge group had significantly smaller deformation, demonstrating better anti-torsional stiffness. This indicates that under the rotational load case, the force-multiplying bridge group had a stronger ability to restrict the rotational displacement of the radius than the steel plate-screw group. Palmar Flexion Load Case Steel Plate-Screw Group (Figure 2 a3): Maximum deformation was approximately 0.37695 mm; Force-Multiplying Bridge Group (Figure 2 b3): Maximum deformation was approximately 0.60467 mm. Analysis: Palmar flexion is a type of bending load. The steel plate-screw group had smaller deformation, indicating that under the palmar flexion load case, the steel plate-screw group had a better ability to control the palmar flexion displacement of the radius and could more effectively restrict deformation in the palmar direction. Dorsiflexion Load Case Steel Plate-Screw Group (Figure 2 a4): Maximum deformation was approximately 0.09147 mm; Force-Multiplying Bridge Group (Figure 2 b4): Maximum deformation was approximately 0.60411 mm. Analysis: The steel plate-screw group had significantly smaller deformation, demonstrating a much better ability to restrict the dorsiflexion displacement of the radius than the force-multiplying bridge group, and could more stably control deformation in the dorsiflexion direction. 2.2 Stress Distribution and Maximum Stress of the Internal Fixation Device The maximum displacement results from Figure 3, categorized by group and load case, are presented in Table 4 below. Table 4 Displacement of the Two Groups Under the Four Load Cases Grouping Axial Rotational Palmar Dorsal Plate-Screw Group 0.15434mm 0.65981mm 0.37598mm 0.09147mm Force-Multiplying Bridge Group 0.24323mm 0.22374mm 0.57387mm 0.57798mm Axial Direction The steel plate-screw group (0.15434 mm) outperformed the force-multiplying bridge group (0.24323 mm) (Figure 3 a1-b1). For the steel plate-screw group, the stress-induced deformation of the screws was mainly concentrated on the screws below the articular surface; while the stress in the force-multiplying bridge group was relatively dispersed, the stress on the screws in the ulnar-palmar direction was more concentrated. This may be attributed to the "slope-like" shape of the radial articular surface: when the articular surface is subjected to axial force, the tangential component of the force travels along the "slope" to the "slope base," resulting in concentrated normal force on this specific screw. Rotational Direction The force-multiplying bridge group (0.22374 mm) outperformed the steel plate-screw group (0.65981 mm) (Figure 3 a2-b2). Its crossed screws and spatial bridge-like structure enable multi-directional anchoring of the radius. Palmar Flexion/Dorsiflexion The steel plate-screw group (palmar flexion: 0.37598 mm; dorsiflexion: 0.09147 mm) outperformed the force-multiplying bridge group (palmar flexion: 0.57387 mm; dorsiflexion: 0.57798 mm) in both directions (Figure 3 a3-b3, a4-b4). The force-multiplying bridge group showed almost consistent results in the two directions, whereas the steel plate-screw group exhibited a significant difference between its palmar flexion and dorsiflexion results. 2.3 Stress Distribution and Stress Peak of the Articular Surface In general, the articular surface deformation of the force-multiplying bridge group was smaller, and the main deformation of this group was dominated by the bending deformation of the screws and the middle-proximal part of the radius. In contrast, the articular surface of the steel plate-screw group showed "bloom-like" deformation, with no obvious articular surface deformation observed only under the rotational load case. Axial Load Case In the deformation nephogram of the steel plate-screw group (Figure 4 a1), the high-deformation areas (red and yellow) were widely distributed at the articular surface, indicating a certain degree of relative displacement of the articular surface bone fragments. The force-multiplying bridge group (Figure 4 b1) showed more uniform deformation, with a smaller proportion of high-deformation areas. Through its multi-directional support structure, the force-multiplying bridge group disperses axial forces, which is more conducive to maintaining the anatomical alignment of the articular surface. Rotational Load Case The deformation of both the steel plate-screw group (Figure 4 a2) and the force-multiplying bridge group (Figure 4 b2) showed uniform "concentric circle"-like diffusion. However, the displacement of the force-multiplying bridge group (0.23078 mm) was smaller than that of the steel plate-screw group (0.65981 mm). This may be because the spatial cross-fixation structure of the force-multiplying bridge can anchor bone fragments in multiple directions, effectively resisting torsion and resulting in almost no separation of the articular surface. Palmar Flexion Load Case In the steel plate-screw group (Figure 4 a3), the range of red/yellow high-deformation areas at the articular surface was large, indicating obvious bending and displacement of the articular surface during palmar flexion. The deformation of the force-multiplying bridge group (Figure 4 b3) was mainly orange/yellow and more concentrated in distribution, with more controllable overall displacement of the articular surface. This shows that the structural design of the force-multiplying bridge is more conducive to dispersing palmar flexion forces and reducing articular surface deformation. Dorsiflexion Load Case The articular surface of the steel plate-screw group (Figure 4 a4) showed obvious "zoned deformation" (clear boundaries between areas of different colors), reflecting that the articular surface bone fragments are prone to local displacement during dorsiflexion. The deformation of the force-multiplying bridge group (Figure 4 b4) was mainly red and more uniform overall, with better integrity of the articular surface. Discussion 3.1 Core Mechanism of Differences in Biomechanical Performance Between the Two Internal Fixation Groups In the fields of bridge engineering and structural mechanics, the force-multiplying bridge is often used in scenarios requiring temporary emergency response or rapid erection, and it belongs to a modular truss system. Its mechanical response characteristics are as follows: under the action of initial load, elastic deformation initiates → the truss force flow is gradually connected → the overall support system takes shape → mechanical balance is stabilized [1] . After the structure is formed, it can bear a load several times that of its own material. Therefore, theoretically, it is reasonable to apply this structure to the internal fixation of fractures. However, unlike the flat surface of a bridge deck, the articular surface is uneven. Hence, in this experiment, the entire upper support surface of the force-multiplying bridge was designed into a slope shape to fit the slope-shaped articular surface of the radius, as shown in Fig. 1c1. This experiment has also fully proved that the force-multiplying bridge structure can achieve performance comparable to that of conventional plate internal fixation with much less material. Axial Load (20 N) The multi-directional screws of the force-multiplying bridge can anchor the fracture fragments from different angles, dispersing the axial pressure to a larger range of bone tissue and avoiding articular surface separation caused by local stress concentration. Although the steel plate-screw group provides support through "plate-bone surface contact", the single-plane screw layout results in a narrow range of axial force dispersion, leading to a higher risk of local deformation of the articular surface (steel plate group: 0.154 mm vs. force-multiplying bridge group: 0.243 mm). Although the value of the steel plate group is slightly smaller, the articular surface deformation of the force-multiplying bridge group is more uniform, with no local protrusion or separation. Torsional Load (1 N·m) This is the load case where the force-multiplying bridge group shows the most significant advantage (force-multiplying bridge group: 0.293 mm vs. steel plate group: 0.660 mm). Its spatially crossed screw layout forms a "three-dimensional anti-torsion frame" [4] , which can effectively restrict the rotational displacement of the distal radius around the axis and prevent "step-like separation" of the articular surface. In contrast, the screws of the steel plate-screw group are mostly arranged along the long axis of the radius, resulting in weak anti-torsional moment capacity and easily causing relative torsional displacement between the bone fragments of the articular surface. Bending Load (Palmar Flexion/Dorsal Extension, 5 N) The two types of internal fixation show "differentiation of local advantages". The steel plate-screw group exhibits a local stiffness advantage under the palmar flexion load case. Since the steel plate fits the palmar side of the distal radius, it can directly resist the bending moment during palmar flexion and reduce local articular surface deformation. However, under the dorsiflexion load case, the "single-plane support" of the steel plate is difficult to cope with the bending force in the palmar direction [5] , leading to significant dislocation of the articular surface in the steel plate-screw group. Although the absolute deformation value of the force-multiplying bridge group under palmar flexion/dorsiflexion is slightly higher than that of the steel plate group, the overall deformation of the articular surface is more uniform, with no phenomena such as articular surface separation—and this is exactly the goal of surgical reduction. 3.2 Clinical Significance: Correlation Between Articular Surface Stability and Long-Term Prognosis The core clinical goal for distal radius fractures is to "restore the flatness of the articular surface and reduce the risk of post-traumatic arthritis" — a need that the findings of this study exactly address [6] . The force-multiplying bridge group is characterized by "almost no articular surface separation", which can directly reduce postoperative articular surface irregularity (an irregularity > 1 mm significantly increases the risk of arthritis). This is particularly important for patients with intra-articular fractures (AO Classification Type C) [7], and the multi-directional fixation of the force-multiplying bridge can fundamentally reduce this risk. In addition, attention should be paid to a potential issue with the "surface contact" design of the steel plate-screw system: if the fit is poor, a "plate-bone gap" is likely to occur under axial load, which instead increases the risk of articular surface separation. This also explains why, although the steel plate-screw group has a slightly smaller axial deformation value, the uniformity of its articular surface is inferior to that of the force-multiplying bridge group. The structural design of the force-multiplying bridge group is derived from bridge structural engineering. In this experiment, the articular surface was treated as a bridge deck to construct the force-multiplying bridge. However, in most cases, the articular surfaces of the human body are not as flat as bridge decks; therefore, this factor can be incorporated into consideration during the design process to develop a reasonable structure. For example, as shown in Fig. 3b1, the ulnar-palmar screws of the force-multiplying bridge group exhibit significant deformability. This may be due to the vector decomposition of the axial force, where the tangential component force accumulates on the ulnar-palmar screws along the slope of the articular surface. In future experimental designs involving the application of force-multiplying bridge structures to the internal fixation of fractured articular surfaces, such factors can be taken into account to develop more reasonable force-multiplying bridge structures. 3.3 Model Rationality and Clinical Applicability of the Results The load case settings in this study are highly consistent with clinical practice: the load parameters (20 N for axial direction, corresponding to daily light weight-bearing; 1 N·m for torsion, corresponding to movements such as wringing a towel; 5 N for palmar flexion/dorsiflexion, corresponding to early rehabilitation activities) all fall within the range of activities permitted after clinical surgery. The results can directly provide references for postoperative rehabilitation protocols. For instance, patients in the force-multiplying bridge group can start rotational activities earlier after surgery (due to its superior anti-torsional stability), while rotational movements of patients in the steel plate-screw group need to be appropriately restricted to avoid articular surface separation. Conclusions With its ultra-simplified design using only 6 screws, the Force-Multiplying Bridge-structured internal fixation system achieves optimized load distribution through a triangular truss configuration. It not only attains overall stability comparable to that of the traditional plate-screw system but also exhibits significant advantages in terms of articular surface fixation performance. This innovative design provides a new interdisciplinary design approach based on engineering structures for the internal fixation treatment of complex intra-articular fractures. Implications for Clinical Application: For patients with intra-articular fractures of the distal radius (where strict maintenance of articular surface flatness is required) or those who need to carry out rotational functional exercises at an early stage after surgery, force-multiplying bridge internal fixation is a better choice. For patients whose fracture lines do not involve the articular surface and whose activities are mainly dorsiflexion-based, the steel plate-screw group can meet the basic fixation needs; however, attention should be paid to controlling rotational activities to avoid articular surface separation. Declarations Authors' Contributions First Authorr Xie-Huo：Completed the core work and partial translation of the thesis, including project design, model development, finite element analysis, and thesis drafting. Corresponding Author/Second Author Cao-Yixuan: Completed the submission work and the translation of some papers. Third Author Sun-Ke: Completed the Abstract translation work. Author's Statement This study (Research Title: Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C Fractures) is a finite element numerical analysis study in orthopedics, aiming to explore issues related to the optimization of fracture fixation schemes through biomechanical modeling methods. Throughout the study, we have strictly adhered to the “Declaration of Helsinki of the World Medical Assembly”, the “International Ethical Guidelines for Biomedical Research Involving Human Subjects”, and relevant regulations on medical research ethics in China, and abided by the principles of research integrity and protection of participants' rights and interests. We hereby make the following detailed statements: 1. Ethical Review and Approval If the study is based on human imaging data (CT thin-slice scan data): The study protocol has been reviewed and approved by the Medical Ethics Committee of the Fourth People's Hospital of Longgang District, Shenzhen. The approval number is 202307, and the approval date is October 15, 2023. The study design, data collection and processing procedures are all in line with the requirements of the Ethics Committee. If the study involves secondary use of data (such as reuse of previous clinical imaging data), additional special approval from the Ethics Committee for data reuse has been obtained. 2. Conflict of interest All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. 3. Funding This work was supported by the Longgang District Science, Technology and Innovation Bureau, ShenzhenProject (Approval Year: 2024,Grant No.: LGWJ2023-132). The funders had no role in the design of the study, collection, analysis, or interpretation of data, writing of the manuscript, or decision to publish the results. 4. Data availability The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request. 5. informed consent The volunteer has obtained a comprehensive understanding of the study details, signed the informed consent form, voluntarily participated in the experiment, and consented to the publication of the research findings. References Collins CJ, Atkins PR, Ohs N, et al. Clinical observation of diminished bone quality and quantity through longitudinal HR-pQCT-derived remodeling and mechanoregulation. Sci Rep. 2022 Oct 26;12(1):17960. Prasil L, Andraos R, Rishmany J, et al. Osteosynthesis of an extra-articular distal radius fracture using a palmar locking plate with 4 epiphyseal screws (Gold Standard) versus 2 epiphyseal screws: Finite element analysis. Injury. 2025 Jul;56(7):112360. Hofsteenge JW, Carvalho MA, Botenga ELF, et al. Effect of preparation design on fracture strength of compromised molars restored with direct composite resin restorations: An in vitro and finite element analysis study. J Prosthet Dent. 2024 Jun;131(6):1150-1158. : Zhang G, Li J, Zhang L,et al.Biomechanical Effect of Different Posterior Fixation Techniques on Stability and Adjacent Segment Degeneration in Treating Thoracolumbar Burst Fracture With Osteoporosis: A Finite Element Analysis. Spine (Phila Pa 1976). 2024 Aug 1;49(15):E229-E238. Chitkraisorn T, Thaungwilai K, Prateepsawangwong B, et al. Fracture resistance, 3-dimensional finite element analysis,and safety factors for five post-and-core restorations with crowns placed in the noncircular-shaped canals of premolars. J Prosthet Dent. 2025 Feb;133(2):512.e1-512.e9. Li SJ, Huang HJ, Li CT, et al. Mechanical effect of changed femoral neck ante-version angles on the stability of an intertrochanteric fracture fixed with PFNA: A finite element analysis. Heliyon. 2024 May 17;10(10):e31480. Zhang KR, Luo B, Tu J,et al.A finite element study for tibial fractures: analyze the biomechanical condition of the tibial fracture area to provide guidance for subsequent treatment. Front Bioeng Biotechnol. 2025 Jun 20;13:1532207. 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-8612025","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":582703442,"identity":"6fdc25db-a6ea-4efa-af22-ff9e2cfb245e","order_by":0,"name":"huo xie","email":"","orcid":"","institution":"The Fourth People's Hospital of Longgang District, Shenzhen","correspondingAuthor":false,"prefix":"","firstName":"huo","middleName":"","lastName":"xie","suffix":""},{"id":582703445,"identity":"954ad0fd-796b-4a25-b75a-e573a1347a49","order_by":1,"name":"Yixuan Cao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABA0lEQVRIiWNgGAWjYLCCBBDB3tj4+IeBhBwbe/sBIrXwHD5szFBgY8zHcyaBSKsk0tKkGT6kJc6TcDDAq5C//fAxiYdth+XNGXIMpAsMDqe3SQBt/VGxDbfZZ9LSJBLOHDbc2XDGwHiGweHcNunGA4w9Z27j1GLAkGMmkVBxmHHDwR6DBB6QFpkDCcyMbXi08L8BajE4bL/hMI/BAaCWdDYgF78WCYgtiRuOsSU28xikJRDUInHjWbJFwpn05A1nmA8zzjCwMWwDBvJBfH7h708+ePNnm7XthvsP2398+CMhL9/efvDBjwrcWoCARQJD6AA+9UDA/IGAglEwCkbBKBjpAADUal0IolFYpAAAAABJRU5ErkJggg==","orcid":"","institution":"ShenZhen People’s Hospital","correspondingAuthor":true,"prefix":"","firstName":"Yixuan","middleName":"","lastName":"Cao","suffix":""},{"id":582703448,"identity":"eb1353b3-c212-44a3-99ec-419bf1f61b06","order_by":2,"name":"Ke Sun","email":"","orcid":"","institution":"The Fourth People's Hospital of Longgang District, Shenzhen","correspondingAuthor":false,"prefix":"","firstName":"Ke","middleName":"","lastName":"Sun","suffix":""}],"badges":[],"createdAt":"2026-01-15 15:38:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8612025/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8612025/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101786590,"identity":"30704feb-dd18-454d-9317-413fc0d09582","added_by":"auto","created_at":"2026-02-03 15:42:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":184301,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic Diagram of Experimental Model Fabrication (Preliminary).a: Distal radius Type C fracture model;b: Assembly model of the steel plate-screw group;b1: Configuration of the steel plate and screws for the distal radius;c: Assembly model of the force-multiplying bridge group;c1: Force-multiplying bridge configuration constructed with six screws.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8612025/v1/58a4338ebac406c5bc05c7d0.png"},{"id":101786654,"identity":"151d0cca-026a-4bf4-bdc2-56d5837fcbf7","added_by":"auto","created_at":"2026-02-03 15:42:12","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":374317,"visible":true,"origin":"","legend":"\u003cp\u003eshows the results of the four loading conditions for the two groups of models as follows. a1: Axial load case of the steel plate-screw group;b1: Axial load case of the force-multiplying bridge group;a2: Rotational load case of the steel plate-screw group;b2: Rotational load case of the force-multiplying bridge group;a3: Palmar flexion load case of the steel plate-screw group;b3: Palmar flexion load case of the force-multiplying bridge group;a4: Dorsiflexion load case of the steel plate-screw group;b4: Dorsiflexion load case of the force-multiplying bridge group.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8612025/v1/29f772bc38a0c9914b207fb8.png"},{"id":101786651,"identity":"19c249c5-b90f-4643-98b0-577be06f9aad","added_by":"auto","created_at":"2026-02-03 15:42:11","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":328724,"visible":true,"origin":"","legend":"\u003cp\u003eshows the results of the four loading conditions for the internal fixation devices of the two groups of models as follows. a1: Axial load case of the steel plate-screw group;b1: Axial load case of the force-multiplying bridge group;a2: Rotational load case of the steel plate-screw group;b2: Rotational load case of the force-multiplying bridge group;a3: Palmar flexion load case of the steel plate-screw group;b3: Palmar flexion load case of the force-multiplying bridge group;a4: Dorsiflexion load case of the steel plate-screw group;b4: Dorsiflexion load case of the force-multiplying bridge group.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8612025/v1/0822bd3c4c2e86e5b7424ede.png"},{"id":101786586,"identity":"0de816c7-e636-4252-8d38-b56264f1a4e5","added_by":"auto","created_at":"2026-02-03 15:42:01","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":282963,"visible":true,"origin":"","legend":"\u003cp\u003eCloud Diagrams of Articular Surface Deformation for the Two Groups of Models. a1: Condition of the articular surface in the axial load case of the steel plate-screw group;b1: Condition of the articular surface in the axial load case of the force-multiplying bridge group;a2: Condition of the articular surface in the rotational load case of the steel plate-screw group;b2: Condition of the articular surface in the rotational load case of the force-multiplying bridge group;a3: Condition of the articular surface in the palmar flexion load case of the steel plate-screw group;b3: Condition of the articular surface in the palmar flexion load case of the force-multiplying bridge group;a4: Condition of the articular surface in the dorsiflexion load case of the steel plate-screw group;b4: Condition of the articular surface in the dorsiflexion load case of the force-multiplying bridge group.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8612025/v1/b017a0257244598cbaa7e2f1.png"},{"id":101942818,"identity":"2d113cc8-d467-4334-9f31-986e9f5ddabb","added_by":"auto","created_at":"2026-02-05 09:38:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2117468,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8612025/v1/32a1d689-d28c-49a2-a9f6-2aecfc120c09.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C Fractures","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe Force-Multiplying Bridge is an innovative configuration designed based on mechanical optimization. Its core comprises assemblable truss units, high-strength connectors, and load-bearing panels, and it relies on the geometric stability of triangles to establish a force transmission system \u003csup\u003e[1]\u003c/sup\u003e. A key feature of this structure lies in its ability to achieve load distribution through rational structural layout: it transmits external forces evenly to each stress-bearing component, while leveraging the mechanical amplification effect to significantly enhance overall load-bearing capacity with a relatively small amount of materials. In the field of engineering, this structure has been widely applied in scenarios such as wartime bridge construction and emergency access establishment for disaster relief, thanks to its advantages of convenient assembly and adjustable span, demonstrating excellent mechanical stability and adaptability.​\u003c/p\u003e \u003cp\u003eIn the AO classification of distal radius fractures, Type C fractures are intra-articular fractures, which generally require open reduction and internal fixation (ORIF) in clinical practice. Traditional plate-screw internal fixation often suffers from uneven mechanical distribution of the fixation structure, leading to local stress concentration \u003csup\u003e[2]\u003c/sup\u003e. This issue is prone to causing complications such as fixation loosening, screw breakage, and delayed fracture healing. The introduction of the force-multiplying bridge structure into fracture screw internal fixation can effectively alleviate local stress concentration through its load dispersion and stress optimization characteristics. It enhances the overall stability of the fixation system via a mechanical amplification effect \u003csup\u003e[3]\u003c/sup\u003e, providing a mechanical environment for the fracture site that better meets physiological needs. Meanwhile, it reduces the risk of fatigue failure of internal fixation devices, offering a new fixation scheme for the treatment of Type C distal radius fractures. If implemented, this scheme can provide a more minimally invasive treatment approach compared to traditional plate-screw fixation, creating a more favorable recovery environment for patients' postoperative rehabilitation.\u003c/p\u003e"},{"header":"Materials/Subjects and Methods","content":"\u003cp\u003e\u003cstrong\u003e1.1 Design:\u003c/strong\u003e A C-type fracture model (intra-articular four-part fracture) was constructed based on the distal radius fracture model. The articular surface was used as the bridge deck, and a force-multiplying bridge structure was built with 6 screws, as shown in Figure 1 c1. The state after the 6 screws were inserted into the distal radius is shown in Figure 1 c.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.2 Time and Location:\u003c/strong\u003eThe experiment was conducted at the Fourth People\u0026apos;s Hospital of Longgang District, Shenzhen from June to August 2025.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.3 Materials/Subjects\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOne 40-year-old healthy female volunteer was selected, with a height of 160 cm, no previous forearm trauma or other diseases. The volunteer\u0026apos;s distal radius CT data were acquired and saved in DICOM format. This study was approved by the Medical Ethics Committee of the Fourth People\u0026apos;s Hospital of Longgang District, Shenzhen, with the approval number: 202307. The volunteer signed the informed consent form and voluntarily agreed to participate in this study. The experiment strictly adhered to the principles and norms formulated by the Medical Ethics Committee of the hospital.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.4 Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.4.1 Establishment of the Distal Radius Type C Fracture Model\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA thin-slice CT scan was performed layer by layer on the volunteer\u0026apos;s intact forearm to acquire complete DICOM data of the radius. Subsequently, Mimics 21.0 software was used to import the radius DICOM data. Appropriate grayscale values were set for the data, followed by operations including threshold segmentation, region growing, and mask editing to fill gaps. Then, region growing was conducted again to isolate the radius individually and fill voids within it. The segmented mask was used to generate a 3D model; after confirming that all osseous landmarks of the radius were intact, the model was smoothed and exported in STP format.\u003c/p\u003e\n\u003cp\u003eThe STP format model was imported into Geomagic Wrap 2017 software. Operations such as 3D surface patch subdivision, noise reduction, feature removal, grid construction, and surface fitting were performed to establish a solid model of the radial cortical bone. An offset operation was applied to this cortical bone model to obtain a solid model of the cancellous bone, which was then saved separately in STP format.\u003c/p\u003e\n\u003cp\u003eFurther, the established models were imported into SolidWorks 2021. The cortical bone and cancellous bone models were assembled using the origin mating command and saved in a part file format. According to the AO fracture classification, the model was processed to create a fracture model, as shown in Figure 1 a below.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.4.2 Grouped Assembly\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this experiment, a steel plate-screw group and a force-multiplying bridge group were set up for comparative analysis. The steel plates were provided by Xiamen Dabo Medical Technology Co., Ltd., and both groups used 2.7 mm-sized screws.\u003c/p\u003e\n\u003cp\u003eAmong them, the assembled steel plate-screw group is shown in Figure 1 b, and the steel plate and screws are shown in Figure 1 b1; the assembled force-multiplying bridge group is shown in Figure 1 c. For the construction of the force-multiplying bridge screws, the articular surface was used as the bridge deck, and the ulnar and radial sides served as the two ends of the \u0026quot;bank\u0026quot;. Screws of the same specification as those in the steel plate-screw group were used for construction (as shown in Figure 1 c1), with a total of 6 screws employed.\u003c/p\u003e\n\u003cp\u003eThe assembled assemblies of the two groups, completed using SolidWorks 2021, are shown in Figure 1 b and Figure 1 c respectively. The assemblies were saved separately as XT files.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.5 Finite Element Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.5.1 Material Assignment and Mesh Generation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe two groups of models mentioned above were imported into the finite element analysis software ANSYS 17.0 respectively, and a static analysis module was created. The elastic moduli and Poisson\u0026apos;s ratios of cortical bone, cancellous bone, steel plates, and screws are listed in Table 1.\u003c/p\u003e\n\u003cp\u003eContact Settings: A frictional contact with a friction coefficient of 0.4 was adopted between the steel plate-screw and the bone, while a bonded contact was used between the screws and the steel plate.\u003c/p\u003e\n\u003cp\u003eTetrahedral elements were used for mesh generation of the models, with a mesh size of 1 mm. The number of nodes and meshes for each group of models are shown in Table 2.\u003c/p\u003e\n\u003cp\u003eTable 1 Material Parameters of the Model\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eMaterial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eElastic Modulus (MPa)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003ePoisson\u0026apos;s Ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eCortical Bone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e17 000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eCancellous Bone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e13 000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003ePlate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e110 000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eScrews\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e109 000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2 Number of Nodes and Elements of the Two Groups of Models After Mesh Generation\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003eModel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26px;\"\u003e\n \u003cp\u003eNumber of Nodes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 29px;\"\u003e\n \u003cp\u003eNumber of Elements\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003ePlate-Screw Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26px;\"\u003e\n \u003cp\u003e589191\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 29px;\"\u003e\n \u003cp\u003e318573\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003eForce-Multiplying Bridge Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26px;\"\u003e\n \u003cp\u003e367362\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 29px;\"\u003e\n \u003cp\u003e201202\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e1.5.2 Loading Conditions and Boundary Conditions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this study, simulation tests of loads in four directions were conducted on the two groups of models, namely axial, dorsal extension, palmar flexion, and rotation. The loading conditions were determined based on references:\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eFor the axial movement of the radius: A 20 N axial load was applied to the distal radial articular surface (Loading Condition 1);\u003c/li\u003e\n \u003cli\u003eFor the rotational movement of the radius: A 1 N\u0026middot;m torsional load was applied to the distal radial articular surface (Loading Condition 2);\u003c/li\u003e\n \u003cli\u003eFor the palmar flexion movement of the radius: A 5 N load in the palmar direction was applied to the dorsal part of the distal radial bone surface (Loading Condition 3);\u003c/li\u003e\n \u003cli\u003eFor the dorsal extension movement of the radius: A 5 N load in the radial dorsal extension direction was applied to a selected part of the palmar surface of the distal radius (Loading Condition 4).\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe bone surface near the proximal radius was fully constrained to simulate the fixed state of the proximal radius.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.6 Main Outcome Measures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter applying the four types of loads in different directions to the two groups of models, the following indicators were observed respectively:\u003c/p\u003e\n\u003cp\u003e① Displacement distribution and maximum displacement of the internal fixation model;\u003c/p\u003e\n\u003cp\u003e② Stress distribution and maximum stress of the internal fixation device;\u003c/p\u003e\n\u003cp\u003e③ Stress distribution and maximum stress of the articular surface.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e2.1 Maximum Displacement and Distribution of the Internal Fixation Model\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe force-multiplying bridge group outperformed the steel plate-screw group under the rotational load case (Figure 2 a2-b2), and the two groups showed similar performance under the axial load case (Figure 2 a1-b1). However, the steel plate-screw group exhibited better deformation control under the palmar flexion and dorsiflexion load cases (Figure 2 a3-b3, a4-b5). The force-multiplying bridge group had slightly greater deformation under the palmar flexion and dorsiflexion load cases, but there was no significant difference in the internal comparison of the force-multiplying bridge group under these two load cases (Figure 2 b3-b4). In contrast, the steel plate-screw group showed a significant difference in the internal comparison under the palmar flexion and dorsiflexion load cases (Figure 2 a3-a4), which is attributed to the lack of dorsal support of the volar plate when force is applied in the dorsiflexion direction. Overall, the two groups had roughly comparable biomechanical performance in terms of total deformation, and both could provide effective fixation for the distal radius.\u003c/p\u003e\n\u003cp\u003eThe maximum displacement results from Figure 2, grouped by group and load case, are listed in Table 3 below.\u003c/p\u003e\n\u003cp\u003eTable 3 Displacement of the Two Groups Under Four Load Cases\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003eGrouping\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003eRotational\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003ePalmar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003eDorsal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003ePlate-Screw Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.16356mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.65981mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.37695mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.09147mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003eForce-Multiplying Bridge Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.24323mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.23078mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.60467mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.60411mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eAxial Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eSteel Plate-Screw Group (Figure 2 a1): Maximum deformation was approximately 0.16356 mm;\u003c/li\u003e\n \u003cli\u003eForce-Multiplying Bridge Group (Figure 2 b1): Maximum deformation was approximately 0.24323 mm.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAnalysis:\u0026nbsp;\u003c/strong\u003eThe axial load simulates the weight-bearing pressure of the limb. The deformation of both groups was within a small magnitude range. The force-multiplying bridge group had slightly greater deformation, but the numerical difference was not significant. From the perspective of biomechanical stability, both groups could provide effective axial support for the radius, with the steel plate-screw group having a slight advantage in deformation performance.\u003c/p\u003e\n\u003cp\u003eRotational Load Case\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eSteel Plate-Screw Group (Figure 2 a2): Maximum deformation was approximately 0.65981 mm;\u003c/li\u003e\n \u003cli\u003eForce-Multiplying Bridge Group (Figure 2 b2): Maximum deformation was approximately 0.23078 mm.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAnalysis:\u0026nbsp;\u003c/strong\u003eThe rotational load simulates the torsional movement of the limb. The force-multiplying bridge group had significantly smaller deformation, demonstrating better anti-torsional stiffness. This indicates that under the rotational load case, the force-multiplying bridge group had a stronger ability to restrict the rotational displacement of the radius than the steel plate-screw group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePalmar Flexion Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eSteel Plate-Screw Group (Figure 2 a3): Maximum deformation was approximately 0.37695 mm;\u003c/li\u003e\n \u003cli\u003eForce-Multiplying Bridge Group (Figure 2 b3): Maximum deformation was approximately 0.60467 mm.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAnalysis:\u0026nbsp;\u003c/strong\u003ePalmar flexion is a type of bending load. The steel plate-screw group had smaller deformation, indicating that under the palmar flexion load case, the steel plate-screw group had a better ability to control the palmar flexion displacement of the radius and could more effectively restrict deformation in the palmar direction.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDorsiflexion Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eSteel Plate-Screw Group (Figure 2 a4): Maximum deformation was approximately 0.09147 mm;\u003c/li\u003e\n \u003cli\u003eForce-Multiplying Bridge Group (Figure 2 b4): Maximum deformation was approximately 0.60411 mm.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAnalysis:\u0026nbsp;\u003c/strong\u003eThe steel plate-screw group had significantly smaller deformation, demonstrating a much better ability to restrict the dorsiflexion displacement of the radius than the force-multiplying bridge group, and could more stably control deformation in the dorsiflexion direction.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Stress Distribution and Maximum Stress of the Internal Fixation Device\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe maximum displacement results from Figure 3, categorized by group and load case, are presented in Table 4 below.\u003c/p\u003e\n\u003cp\u003eTable 4 Displacement of the Two Groups Under the Four Load Cases\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003eGrouping\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003eRotational\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003ePalmar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003eDorsal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003ePlate-Screw Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.15434mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.65981mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.37598mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.09147mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 36px;\"\u003e\n \u003cp\u003eForce-Multiplying Bridge Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.24323mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.22374mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.57387mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e0.57798mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAxial Direction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe steel plate-screw group (0.15434 mm) outperformed the force-multiplying bridge group (0.24323 mm) (Figure 3 a1-b1). For the steel plate-screw group, the stress-induced deformation of the screws was mainly concentrated on the screws below the articular surface; while the stress in the force-multiplying bridge group was relatively dispersed, the stress on the screws in the ulnar-palmar direction was more concentrated. This may be attributed to the \u0026quot;slope-like\u0026quot; shape of the radial articular surface: when the articular surface is subjected to axial force, the tangential component of the force travels along the \u0026quot;slope\u0026quot; to the \u0026quot;slope base,\u0026quot; resulting in concentrated normal force on this specific screw.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRotational Direction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe force-multiplying bridge group (0.22374 mm) outperformed the steel plate-screw group (0.65981 mm) (Figure 3 a2-b2). Its crossed screws and spatial bridge-like structure enable multi-directional anchoring of the radius.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePalmar Flexion/Dorsiflexion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe steel plate-screw group (palmar flexion: 0.37598 mm; dorsiflexion: 0.09147 mm) outperformed the force-multiplying bridge group (palmar flexion: 0.57387 mm; dorsiflexion: 0.57798 mm) in both directions (Figure 3 a3-b3, a4-b4). The force-multiplying bridge group showed almost consistent results in the two directions, whereas the steel plate-screw group exhibited a significant difference between its palmar flexion and dorsiflexion results.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Stress Distribution and Stress Peak of the Articular Surface\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn general, the articular surface deformation of the force-multiplying bridge group was smaller, and the main deformation of this group was dominated by the bending deformation of the screws and the middle-proximal part of the radius. In contrast, the articular surface of the steel plate-screw group showed \u0026quot;bloom-like\u0026quot; deformation, with no obvious articular surface deformation observed only under the rotational load case.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAxial Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the deformation nephogram of the steel plate-screw group (Figure 4 a1), the high-deformation areas (red and yellow) were widely distributed at the articular surface, indicating a certain degree of relative displacement of the articular surface bone fragments. The force-multiplying bridge group (Figure 4 b1) showed more uniform deformation, with a smaller proportion of high-deformation areas. Through its multi-directional support structure, the force-multiplying bridge group disperses axial forces, which is more conducive to maintaining the anatomical alignment of the articular surface.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRotational Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe deformation of both the steel plate-screw group (Figure 4 a2) and the force-multiplying bridge group (Figure 4 b2) showed uniform \u0026quot;concentric circle\u0026quot;-like diffusion. However, the displacement of the force-multiplying bridge group (0.23078 mm) was smaller than that of the steel plate-screw group (0.65981 mm). This may be because the spatial cross-fixation structure of the force-multiplying bridge can anchor bone fragments in multiple directions, effectively resisting torsion and resulting in almost no separation of the articular surface.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePalmar Flexion Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the steel plate-screw group (Figure 4 a3), the range of red/yellow high-deformation areas at the articular surface was large, indicating obvious bending and displacement of the articular surface during palmar flexion. The deformation of the force-multiplying bridge group (Figure 4 b3) was mainly orange/yellow and more concentrated in distribution, with more controllable overall displacement of the articular surface. This shows that the structural design of the force-multiplying bridge is more conducive to dispersing palmar flexion forces and reducing articular surface deformation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDorsiflexion Load Case\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe articular surface of the steel plate-screw group (Figure 4 a4) showed obvious \u0026quot;zoned deformation\u0026quot; (clear boundaries between areas of different colors), reflecting that the articular surface bone fragments are prone to local displacement during dorsiflexion. The deformation of the force-multiplying bridge group (Figure 4 b4) was mainly red and more uniform overall, with better integrity of the articular surface.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec25\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Core Mechanism of Differences in Biomechanical Performance Between the Two Internal Fixation Groups\u003c/h2\u003e \u003cp\u003eIn the fields of bridge engineering and structural mechanics, the force-multiplying bridge is often used in scenarios requiring temporary emergency response or rapid erection, and it belongs to a modular truss system. Its mechanical response characteristics are as follows: under the action of initial load, elastic deformation initiates \u0026rarr; the truss force flow is gradually connected \u0026rarr; the overall support system takes shape \u0026rarr; mechanical balance is stabilized \u003csup\u003e[1]\u003c/sup\u003e. After the structure is formed, it can bear a load several times that of its own material. Therefore, theoretically, it is reasonable to apply this structure to the internal fixation of fractures. However, unlike the flat surface of a bridge deck, the articular surface is uneven. Hence, in this experiment, the entire upper support surface of the force-multiplying bridge was designed into a slope shape to fit the slope-shaped articular surface of the radius, as shown in Fig.\u0026nbsp;1c1. This experiment has also fully proved that the force-multiplying bridge structure can achieve performance comparable to that of conventional plate internal fixation with much less material.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAxial Load (20 N)\u003c/h3\u003e\n\u003cp\u003eThe multi-directional screws of the force-multiplying bridge can anchor the fracture fragments from different angles, dispersing the axial pressure to a larger range of bone tissue and avoiding articular surface separation caused by local stress concentration. Although the steel plate-screw group provides support through \"plate-bone surface contact\", the single-plane screw layout results in a narrow range of axial force dispersion, leading to a higher risk of local deformation of the articular surface (steel plate group: 0.154 mm vs. force-multiplying bridge group: 0.243 mm). Although the value of the steel plate group is slightly smaller, the articular surface deformation of the force-multiplying bridge group is more uniform, with no local protrusion or separation.\u003c/p\u003e\n\u003ch3\u003eTorsional Load (1 N·m)\u003c/h3\u003e\n\u003cp\u003eThis is the load case where the force-multiplying bridge group shows the most significant advantage (force-multiplying bridge group: 0.293 mm vs. steel plate group: 0.660 mm). Its spatially crossed screw layout forms a \"three-dimensional anti-torsion frame\" \u003csup\u003e[4]\u003c/sup\u003e, which can effectively restrict the rotational displacement of the distal radius around the axis and prevent \"step-like separation\" of the articular surface. In contrast, the screws of the steel plate-screw group are mostly arranged along the long axis of the radius, resulting in weak anti-torsional moment capacity and easily causing relative torsional displacement between the bone fragments of the articular surface.\u003c/p\u003e\n\u003ch3\u003eBending Load (Palmar Flexion/Dorsal Extension, 5 N)\u003c/h3\u003e\n\u003cp\u003eThe two types of internal fixation show \"differentiation of local advantages\". The steel plate-screw group exhibits a local stiffness advantage under the palmar flexion load case. Since the steel plate fits the palmar side of the distal radius, it can directly resist the bending moment during palmar flexion and reduce local articular surface deformation. However, under the dorsiflexion load case, the \"single-plane support\" of the steel plate is difficult to cope with the bending force in the palmar direction \u003csup\u003e[5]\u003c/sup\u003e, leading to significant dislocation of the articular surface in the steel plate-screw group. Although the absolute deformation value of the force-multiplying bridge group under palmar flexion/dorsiflexion is slightly higher than that of the steel plate group, the overall deformation of the articular surface is more uniform, with no phenomena such as articular surface separation\u0026mdash;and this is exactly the goal of surgical reduction.\u003c/p\u003e \u003cdiv id=\"Sec29\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Clinical Significance: Correlation Between Articular Surface Stability and Long-Term Prognosis\u003c/h2\u003e \u003cp\u003eThe core clinical goal for distal radius fractures is to \"restore the flatness of the articular surface and reduce the risk of post-traumatic arthritis\" \u0026mdash; a need that the findings of this study exactly address \u003csup\u003e[6]\u003c/sup\u003e. The force-multiplying bridge group is characterized by \"almost no articular surface separation\", which can directly reduce postoperative articular surface irregularity (an irregularity\u0026thinsp;\u0026gt;\u0026thinsp;1 mm significantly increases the risk of arthritis). This is particularly important for patients with intra-articular fractures (AO Classification Type C) \u003csup\u003e[7],\u003c/sup\u003e and the multi-directional fixation of the force-multiplying bridge can fundamentally reduce this risk. In addition, attention should be paid to a potential issue with the \"surface contact\" design of the steel plate-screw system: if the fit is poor, a \"plate-bone gap\" is likely to occur under axial load, which instead increases the risk of articular surface separation. This also explains why, although the steel plate-screw group has a slightly smaller axial deformation value, the uniformity of its articular surface is inferior to that of the force-multiplying bridge group.\u003c/p\u003e \u003cp\u003eThe structural design of the force-multiplying bridge group is derived from bridge structural engineering. In this experiment, the articular surface was treated as a bridge deck to construct the force-multiplying bridge. However, in most cases, the articular surfaces of the human body are not as flat as bridge decks; therefore, this factor can be incorporated into consideration during the design process to develop a reasonable structure. For example, as shown in Fig.\u0026nbsp;3b1, the ulnar-palmar screws of the force-multiplying bridge group exhibit significant deformability. This may be due to the vector decomposition of the axial force, where the tangential component force accumulates on the ulnar-palmar screws along the slope of the articular surface. In future experimental designs involving the application of force-multiplying bridge structures to the internal fixation of fractured articular surfaces, such factors can be taken into account to develop more reasonable force-multiplying bridge structures.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec30\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Model Rationality and Clinical Applicability of the Results\u003c/h2\u003e \u003cp\u003eThe load case settings in this study are highly consistent with clinical practice: the load parameters (20 N for axial direction, corresponding to daily light weight-bearing; 1 N\u0026middot;m for torsion, corresponding to movements such as wringing a towel; 5 N for palmar flexion/dorsiflexion, corresponding to early rehabilitation activities) all fall within the range of activities permitted after clinical surgery. The results can directly provide references for postoperative rehabilitation protocols. For instance, patients in the force-multiplying bridge group can start rotational activities earlier after surgery (due to its superior anti-torsional stability), while rotational movements of patients in the steel plate-screw group need to be appropriately restricted to avoid articular surface separation.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eWith its ultra-simplified design using only 6 screws, the Force-Multiplying Bridge-structured internal fixation system achieves optimized load distribution through a triangular truss configuration. It not only attains overall stability comparable to that of the traditional plate-screw system but also exhibits significant advantages in terms of articular surface fixation performance. This innovative design provides a new interdisciplinary design approach based on engineering structures for the internal fixation treatment of complex intra-articular fractures.\u003c/p\u003e \u003cp\u003eImplications for Clinical Application: For patients with intra-articular fractures of the distal radius (where strict maintenance of articular surface flatness is required) or those who need to carry out rotational functional exercises at an early stage after surgery, force-multiplying bridge internal fixation is a better choice. For patients whose fracture lines do not involve the articular surface and whose activities are mainly dorsiflexion-based, the steel plate-screw group can meet the basic fixation needs; however, attention should be paid to controlling rotational activities to avoid articular surface separation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors' Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eFirst Authorr Xie-Huo：Completed the core work and partial translation of the thesis, including project design, model development, finite element analysis, and thesis drafting.\u003c/li\u003e\n \u003cli\u003eCorresponding Author/Second\u0026nbsp;Author\u0026nbsp;Cao-Yixuan: Completed the submission work and the translation of some papers.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eThird Author Sun-Ke: Completed the Abstract translation work.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor's Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study (Research Title: Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C Fractures) is a finite element numerical analysis study in orthopedics, aiming to explore issues related to the optimization of fracture fixation schemes through biomechanical modeling methods. Throughout the study, we have strictly adhered to the “Declaration of Helsinki of the World Medical Assembly”, the “International Ethical Guidelines for Biomedical Research Involving Human Subjects”, and relevant regulations on medical research ethics in China, and abided by the principles of research integrity and protection of participants' rights and interests. We hereby make the following detailed statements: \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;1. Ethical Review and Approval \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIf the study is based on human imaging data (CT thin-slice scan data): The study protocol has been reviewed and approved by the Medical Ethics Committee of the Fourth People's Hospital of Longgang District, Shenzhen. The approval number is 202307, and the approval date is October 15, 2023. The study design, data collection and processing procedures are all in line with the requirements of the Ethics Committee. If the study involves secondary use of data (such as reuse of previous clinical imaging data), additional special approval from the Ethics Committee for data reuse has been obtained. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e2. Conflict of interest\u003c/p\u003e\n\u003cp\u003eAll authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e3. Funding\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Longgang District Science, Technology and Innovation Bureau, ShenzhenProject (Approval Year: 2024,Grant No.: LGWJ2023-132). The funders had no role in the design of the study, collection, analysis, or interpretation of data, writing of the manuscript, or decision to publish the results.\u003c/p\u003e\n\u003cp\u003e4. Data availability\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e5. informed consent\u003c/p\u003e\n\u003cp\u003eThe volunteer has obtained a comprehensive understanding of the study details, signed the informed consent form, voluntarily participated in the experiment, and consented to the publication of the research findings.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eCollins CJ, Atkins PR, Ohs N, et al. Clinical observation of diminished bone quality and quantity through longitudinal HR-pQCT-derived remodeling and mechanoregulation. Sci Rep. 2022 Oct 26;12(1):17960.\u003c/li\u003e\n \u003cli\u003ePrasil L, Andraos R, Rishmany J, et al. Osteosynthesis of an extra-articular distal radius fracture using a palmar locking plate with 4 epiphyseal screws (Gold Standard) versus 2 epiphyseal screws: Finite element analysis. Injury. 2025 Jul;56(7):112360.\u003c/li\u003e\n \u003cli\u003eHofsteenge JW, Carvalho MA, Botenga ELF, et al. Effect of preparation design on fracture strength of compromised molars restored with direct composite resin restorations: An in vitro and finite element analysis study. J Prosthet Dent. 2024 Jun;131(6):1150-1158.\u003c/li\u003e\n \u003cli\u003e: Zhang G, Li J, Zhang L,et al.Biomechanical Effect of Different Posterior Fixation Techniques on Stability and Adjacent Segment Degeneration in Treating Thoracolumbar Burst Fracture With Osteoporosis: A Finite Element Analysis. Spine (Phila Pa 1976). 2024 Aug 1;49(15):E229-E238.\u003c/li\u003e\n \u003cli\u003eChitkraisorn T, Thaungwilai K, Prateepsawangwong B, et al. Fracture resistance, 3-dimensional finite element analysis,and safety factors for five post-and-core restorations with crowns placed in the noncircular-shaped canals of premolars. J Prosthet Dent. 2025 Feb;133(2):512.e1-512.e9.\u003c/li\u003e\n \u003cli\u003eLi SJ, Huang HJ, Li CT, et al. Mechanical effect of changed femoral neck ante-version angles on the stability of an intertrochanteric fracture fixed with PFNA: A finite element analysis. Heliyon. 2024 May 17;10(10):e31480.\u003c/li\u003e\n \u003cli\u003eZhang KR, Luo B, Tu J,et al.A finite element study for tibial fractures: analyze the biomechanical condition of the tibial fracture area to provide guidance for subsequent treatment. Front Bioeng Biotechnol. 2025 Jun 20;13:1532207.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Distal Radius Type C Fracture, Finite Element Analysis, Force-Multiplying Bridge Structure, Truss Element, Internal Fixation System","lastPublishedDoi":"10.21203/rs.3.rs-8612025/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8612025/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003eObjective\u003c/em\u003e, To analyze the biomechanical performance differences between the Force-Multiplying Bridge structural screw fixation system (a screw arrangement configuration derived from truss elements) and the traditional plate-screw fixation system in the treatment of distal radius type C fractures using finite element analysis.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMethods\u003c/em\u003e, Three-dimensional models of distal radius type C fractures were constructed from radial CT image data using Mimics, Geomagic Wrap, and SolidWorks software. Two groups were established: the plate-screw group and the Force-Multiplying Bridge group. In the Force-Multiplying Bridge group, 6 screws were used to construct a triangular truss support system. Finite element analysis was performed using ANSYS software.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eResults\u003c/em\u003e, Under the axial loading condition, the plate-screw group is slightly superior to the Force-Multiplying Bridge group. Under the rotational working condition, the maximum displacement of the Force-Multiplying Bridge group was significantly better than that of the plate-screw group, showing superior anti-torsion performance. Under the palmar flexion/dorsal extension working conditions, the displacement of the plate-screw group was smaller than that of the Force-Multiplying Bridge group. The articular surfaces of the plate-screw group showed a cracked pattern under axial, palmar flexion, and dorsal extension working conditions, while no obvious separation of the articular surfaces was observed in the Force-Multiplying Bridge group under all working conditions.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConclusion\u003c/em\u003e, The Force-Multiplying Bridge structural screw fixation system not only achieves performance comparable to that of the traditional plate-screw system but also exhibits significant advantages in terms of articular surface fixation.\u003c/p\u003e","manuscriptTitle":"Finite Element Analysis of Force-Multiplying Bridge Structure Applied in Screw Internal Fixation for Distal Radius Type C Fractures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-03 15:41:13","doi":"10.21203/rs.3.rs-8612025/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-26T18:39:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-23T06:41:32+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-17T12:15:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"130367534462920531084952977100746693863","date":"2026-02-05T11:41:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"155171159046547483324693369201899350496","date":"2026-02-04T14:24:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"337237270645996932837425032558595779424","date":"2026-01-29T09:58:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-29T09:33:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-29T01:46:16+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-28T09:45:46+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-20T09:20:05+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-01-20T09:05:29+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"133e2d05-0866-471c-bcce-eb82962620bf","owner":[],"postedDate":"February 3rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":61996695,"name":"Physical sciences/Engineering"},{"id":61996696,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2026-04-23T05:24:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-03 15:41:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8612025","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8612025","identity":"rs-8612025","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}