Biomechanical comparison of a hybrid fixation technique with traditional methods for distal humeral shaft fractures: a finite element analysis

Biomechanical comparison of a hybrid fixation technique with traditional methods for distal humeral shaft fractures: a finite element analysis | 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 Biomechanical comparison of a hybrid fixation technique with traditional methods for distal humeral shaft fractures: a finite element analysis Gang Fu, Shen’ao Wang, Weiqiang Wu, Xiayu Huang, Binbin Jin, Fengfei Lin, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5726545/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 Background Distal humeral shaft fractures pose significant challenges in orthopedic surgery due to their complex anatomy and biomechanical demands. Traditional fixation methods, such as posterolateral locked plating and double reconstruction plating, have limitations, including radial nerve injury risk and insufficient stability. Purpose This study evaluates the biomechanical performance of a hybrid technique combining an intramedullary nail (IMN) with a reconstruction plate (RP) for managing distal humeral shaft fractures. Methods Finite element analysis (FEA) was conducted to compare the biomechanical properties of IMN + RP, posterolateral locked plating, and double reconstruction plating under axial compression, torsional loading, and bending forces. Key outcomes included displacement, stress distribution, and overall stability. Results The IMN + RP technique demonstrated superior biomechanical performance, achieving lower displacement and more balanced stress distribution across all loading conditions. It outperformed traditional methods in minimizing stress concentrations and maintaining fixation stability. Conclusion This study highlights the biomechanical superiority of the IMN + RP technique, providing robust evidence for its application in managing distal humeral shaft fractures. These findings contribute to the understanding of hybrid fixation strategies and support further clinical and experimental validation. Finite element analysis Humeral shaft fractures Intramedullary nail Biomechanical Stress peak Displacement peak Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Distal humeral shaft fractures commonly occur at the transition between the distal triangular and proximal cylindrical bone shapes, a region prone to mechanical weakness [ . 1 , 2 Traditional surgical interventions such as posterolateral plating are widely adopted but carry risks, including extensive soft tissue disruption and potential iatrogenic radial nerve injury. Double plate fixation offers enhanced torsional stability but may exacerbate these complications. 3 Alternatively, minimally invasive anterior plating reduces soft tissue damage but is limited by the distal fragment’s small size and insufficient fixation strength. 4 , 5 To address these challenges, a novel hybrid method combining an intramedullary nail (IMN) with an anterior reconstruction plate (RP) has been proposed. This method minimizes soft tissue damage and reduces the risk of radial nerve injury, achieving favorable clinical outcomes. 6 In this study, finite element analysis (FEA) was employed to compare the biomechanical properties of three fixation methods—posterolateral plating, double reconstruction plating, and IMN + RP—under different loading conditions. The goal is to provide evidence for optimizing surgical techniques for distal humeral shaft fractures. Materials and Methods Study Subjects A healthy 37-year-old male volunteer (175 cm, 75 kg) with no history of humeral disease, trauma, or osteoporosis was selected. X-ray examination confirmed the absence of old fractures, bone tumors, or other pathologies such as trabecular bone reduction or cortical bone thinning. Thin-slice CT scanning (SINOVISION Insitum CT 768, 128-slice) was performed to acquire high-resolution images of the entire humerus. The CT data were saved in standard DICOM format and used for subsequent 3D modeling. This study was approved by the Ethics Committee of the Fuzhou Second General Hospital (Approval No. 2022086), and informed consent was obtained. Construction of the Humerus 3D Mode The DICOM files were imported into Mimics 21.0 (Materialise, Belgium) for image segmentation and geometric modeling of the humerus. Noise reduction and selective segmentation defined the boundaries of bone and soft tissue, generating an STL file of the humeral shaft. The STL file was imported into Geomagic Studio 12.0 (Raindrop Geomagic, USA) for optimization, including smoothing irregular surfaces and eliminating self-intersecting areas. A smooth surface was fitted to create a continuous solid model. To simulate an A-type fracture, a 1 cm-wide gap was introduced at the distal humerus. Fracture and Internal Fixation Models The optimized humeral shaft model was imported into Siemens NX (Siemens, Germany) to simulate anatomical reduction and construct three internal fixation models: Posterolateral Locked Plate (Group A): Plate thickness 4.5 mm; screw diameter 3.5 mm (Zheng Tian, Tian Jin ). Intramedullary Nail + Reconstruction Plate (Group B): Nail diameter 7 mm, length 285 mm; plate thickness 3 mm; screw diameter 3.5 mm (Zheng Tian, Tian Jin ). Double Reconstruction Plate (Group C): Two plates with a thickness of 3 mm; screw diameter 3.5 mm (Zheng Tian, Tian Jin ).These fixation models were assembled with the humeral shaft to complete the 3D finite element models for the distal humeral shaft fractures(Fig. 1 ). Material Properties Material Assumptions: Bone and implants were modeled as isotropic, homogeneous, and linear elastic materials. The humerus was simplified as cortical bone to analyze static stress distribution under quasi-static loading. Material properties were assigned based on literature values (Table 1 ). Table 1 Material Properties of the Models Material Elastic Modulus (MPa) Poisson’s Ratio Yield Strength (MPa) Bone Model 17000 0.30 - Internal Fixation (Nail, Plate, Screws) 110000 0.33 860 Boundary Conditions and Load Scenarios: Three loading conditions were simulated:Axial Compression: A 200 N load was applied at the distal end while the proximal humerus was fixed.Internal Rotation Torque: A 30 Nm torque was applied at the distal end with the proximal humerus fixed.Three-Point Bending: The proximal and distal ends of the humerus were fixed, and a 30 N load was applied posterior-to-anterior at the fracture site of the distal humerus, simulating a posterior impact on the upper arm. Meshing: Adaptive meshing was applied with a grid size of 0.8 mm at implant interfaces and 3 mm for other regions of the humerus. The total node and element counts for each model are detailed in Table 2 . Table 2 Nodes and Elements for Each Model. Group Nodes Elements Group A 68524 314471 Group B 146997 684115 Group C 57043 256995 Note : Group A: Posterolateral locked plate fixation model.Group B: Intramedullary nail + reconstruction plate fixation model.Group C: Double reconstruction plate fixation model. Results Axial Compression Under axial compression, the displacement and maximum stress values differed across the three groups Group C (Double Reconstruction Plates) exhibited the least displacement, indicating superior stability under compressive loads. However, Group B (Intramedullary Nail + Reconstruction Plate) displayed slightly higher displacement but achieved a more balanced stress distribution, effectively reducing the risk of stress concentration at the implant interface. In contrast, Group A (Posterolateral Locked Plate) exhibited the highest displacement and stress values, reflecting poor stability under compressive loads(Fig. 2 ). Internal Rotation Torque Under a 30 Nm internal rotation torque, Group B demonstrated the lowest displacement (2.791 mm) and stress values (860.30 MPa), indicating enhanced torsional stability. Group C performed adequately, with slightly higher displacement (5.698 mm) and localized stress concentrations near the distal screws, potentially increasing the risk of fatigue failure. Group A displayed the weakest performance, with the highest displacement (21.830 mm) and stress (1065.45 MPa), highlighting its limited torsional stability(Fig. 3 ). Three-Point Bending In three-point bending simulations, Group B showed the lowest displacement (0.022 mm) and stress values (16.56 MPa), demonstrating superior resistance to bending forces. Group C exhibited moderate performance, with slightly higher displacement (0.028 mm) and stress concentrations localized along the proximal plate. Group A showed the weakest bending resistance, with the highest displacement (0.032 mm) and stress values (17.31 MPa) concentrated at the fracture gap(Fig. 4 ). Summary of Biomechanical Findings Overall, Group B (Intramedullary Nail + Reconstruction Plate) demonstrated the best biomechanical performance, with consistent stability and uniform stress distribution across all loading conditions. Group C (Double Reconstruction Plates) showed strong compressive resistance but exhibited localized stress concentrations under certain scenarios. Group A (Posterolateral Locked Plate) performed the weakest, with significant stress concentrations and poor stability across all tests (Table 3 ). Table 3 Maximum Stress, Maximum Displacement, and Stiffness of Three Internal Fixation Models under Axial Compression, Torsion, and Bending Group Axial Compression Torsion Three-Point Bending Stiffness Max Stress(MPa) Max Displacement(mm) Max Stress(MPa) Max Displacement(mm) Max Stress(MPa) Max Displacement(mm) Compression (N/mm) Torsion (Nm/°) Three-Point Bending (N/mm) Group A 344.05 2.739 1065.45 21.830 17.31 0.032 779.30 1.08 999.99 GroupB 47.31 0.415 860.30 2.791 16.56 0.022 6033.35 5.61 1322.94 GroupC 72.71 0.338 936.00 5.698 18.32 0.028 7567.48 2.97 1152.11 Discussion Main Findings This study demonstrated the superior biomechanical performance of the IMN + RP technique for distal humeral shaft fractures. The technique consistently exhibited lower displacement and balanced stress distribution under all loading conditions, effectively addressing the mechanical challenges of these fractures. By minimizing stress concentrations and maintaining robust fixation strength, this approach reduces implant failure risks and improves clinical outcomes. Posterolateral locked plates, while widely used, exhibit significant displacement and stress concentration at the fracture gap, compromising stability. 7 , 8 Compared to traditional methods, double reconstruction plates provide excellent compressive resistance but are associated with extensive soft tissue dissection and a higher risk of iatrogenic radial nerve injury. 3 , 9 , 10 In contrast, the IMN + RP technique balances stress distribution and addresses these limitations, offering a robust and innovative solution for managing complex distal humeral shaft fractures. Clinical Implications The IMN + RP technique offers significant clinical advantages. By preserving vascularity and minimizing soft tissue dissection, it reduces the risks of infection and delayed union. Additionally, the anterior minimally invasive plating decreases the likelihood of radial nerve injury, a common complication associated with traditional methods. 11 , 12 , 13 These biomechanical and clinical benefits support earlier postoperative rehabilitation and better functional recovery for patients with distal humeral shaft fractures. In our clinical practice, this technique was applied to treat 40 patients with distal humeral shaft fractures. No cases of iatrogenic radial nerve injury or fracture nonunion were observed. At the final follow-up, the shoulder joint's Constant score averaged 82.77, while the Mayo Elbow Performance Score averaged 90.5, demonstrating excellent functional outcomes(Fig. 5 ). Strengths and Limitations A major strength of this study is the integration of finite element analysis with clinical insights, enabling a comprehensive evaluation of fixation methods under diverse loading scenarios. However, this study is not without limitations. The finite element models did not account for biological factors, such as bone remodeling and soft tissue recovery, that influence fracture healing. Additionally, the simulated loading conditions may not fully replicate dynamic forces encountered during daily activities. Future studies should incorporate in vivo validations and long-term clinical outcomes to enhance the generalizability of these findings. Conclusion The intramedullary nail combined with a reconstruction plate (IMN + RP) demonstrated superior biomechanical performance compared to posterolateral locked plating and double reconstruction plating for distal humeral shaft fractures. By achieving enhanced stability and balanced stress distribution, the IMN + RP technique provides a minimally invasive and effective alternative for managing complex distal humeral fractures. Further clinical validation and dynamic loading studies are warranted to confirm its long-term efficacy and safety. Declarations Clinical trial number: Not applicable Acknowledgements ： Not applicable Author contributions ： All authors had full access to the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Conceptualization, Renbin Li and Fengfei Lin; methodology,Gang Fu and Weiqiang Wu；investigation,Gang Fu,Shen’ao Wang，Xiayu Huang and Binbin Jin; formal analysis,Shen’ao Wang, Weiqiang Wu，Xiayu Huang and Binbin Jin; writing-original draft,Gang Fu and Shen’ao Wang; writing-review and editing, Fengfei Lin and Renbin Li; supervision, Renbin Li;funding acquisition, Fengfei Lin and Renbin Li. Funding ： This study was funded Program for Fujian Provincial Clinical Medical Research Center for First Aid and Rehabilitation in Orthopaedic Trauma (2020Y2014);The Science and Technology Planning Project of Fuzhou (2022-S-053) Ethics approval and consent to participate ： Institutional Review Board approval was received from the ethics committee of Fuzhou second hospital (2022086) and all consents were signed to participate and publish. Consent for publication: All presentations of case reports have consent for publication. Availability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests: The authors declare that they have no competing interests. References Karadeniz E, Demiroz S, Oktem F, Memisoglu K, Kesemenli CC. Humeral fractures sustained during arm wrestling. Eur J Trauma Emerg Surg. 2022 Aug;48(4):3109-3114. doi: 10.1007/s00068-021-01852-4. Ogawa K, Yoshida A, Matsumura N, Inokuchi W. Fractures of the humeral shaft caused by arm wrestling: a systematic review. JSES Rev Rep Tech. 2022 Jun 22;2(4):505-512. doi: 10.1016/j.xrrt.2022.05.005. Sharaby, M., & Elhawary, A. (2012). A simple technique for double plating of extraarticular distal humeral shaft fractures. Acta orthopaedica Belgica , 78 (6), 708–713. Wu X, Ye Y, Zhu Y, Lin Y, Zhang G, Zhuang Y, Xu Y, Tu S. Modified medial approach for the treatment of fractures of the lower third of the humeral shaft: An anatomical study. Injury. 2024 Dec;55(12):111933. doi: 10.1016/j.injury.2024.111933. Westrick E, Hamilton B, Toogood P, Henley B, Firoozabadi R. Humeral shaft fractures: results of operative and non-operative treatment. Int Orthop. 2017 Feb;41(2):385-395. doi: 10.1007/s00264-016-3210-7. Fu G, Zhang Y, Ke S, Zhu D, Wu J, Su D, Ge H, Chen J, Mb YZ, Lin F, Chen J, Li R. Treatment of Distal Third Humeral Shaft Fracture with Intramedullary Nail Combined with Anterior Minimally Invasive Plate Osteosynthesis. Orthop Surg. 2023 Dec;15(12):3101-3107. doi: 10.1111/os.13893. Cañada-Oya H, Cañada-Oya S, Zarzuela-Jiménez C, Delgado-Martinez AD. New, Minimally Invasive, Anteromedial-Distal Approach for Plate Osteosynthesis of Distal-Third Humeral Shaft Fractures: An Anatomical Study. JB JS Open Access. 2020 Mar 12;5(1):e0056. doi: 10.2106/JBJS.OA.19.00056. Pastor T, Zderic I, van Knegsel KP, Beeres FJP, Migliorini F, Babst R, Nebelung S, Ganse B, Schoeneberg C, Gueorguiev B, Knobe M. Biomechanical analysis of helical versus straight plating of proximal third humeral shaft fractures. Arch Orthop Trauma Surg. 2023 Aug;143(8):4983-4991. doi: 10.1007/s00402-023-04814-0. Saha MK, Islam SS, Alam S, Rahman MW, Kamruzzaman M, Paul J, Rahman MM, Alamgir MK. Evaluation of Fixation for Distal Humeral Diaphyseal Fracture by Locking Compression Plate. Mymensingh Med J. 2019 Jan;28(1):60-69. An Z, Zeng B, He X, Chen Q, Hu S. Plating osteosynthesis of mid-distal humeral shaft fractures: minimally invasive versus conventional open reduction technique. Int Orthop. 2010 Feb;34(1):131-5. doi: 10.1007/s00264-009-0753-x. Contreras JJ, Soto D, Valencia M, López M, Díaz A, Delgado S, Lu CY, Muñoz M, Cortés F, Díaz C, Beltrán M. Treatment of distal third humeral shaft fractures with posterior minimally invasive plate osteosynthesis (MIPO) with segmental isolation of the radial nerve: minimum one-year follow-up. JSES Rev Rep Tech. 2023 Sep 30;4(1):53-60. doi: 10.1016/j.xrrt.2023.08.006. Entezari V, Olson JJ, Vallier HA. Predictors of traumatic nerve injury and nerve recovery following humeral shaft fracture. J Shoulder Elbow Surg. 2021 Dec;30(12):2711-2719. doi: 10.1016/j.jse.2021.04.025. Shimamoto Y, Tokutake K, Takegami Y, Asami Y, Sato K, Ueno H, Nakano T, Fujii S, Okui N, Imagama S. Comparative Outcomes of Anterior and Posterior Plating for Distal-Third Humerus Shaft Fractures. J Hand Surg Am. 2023 Sep 7:S0363-5023(23)00389-1. doi: 10.1016/j.jhsa.2023.07.014. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-5726545","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":396376353,"identity":"247f121e-54d6-4374-a1e2-4eb95b0370d3","order_by":0,"name":"Gang Fu","email":"","orcid":"","institution":"Fuzhou Second General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Gang","middleName":"","lastName":"Fu","suffix":""},{"id":396376354,"identity":"8b28d7e7-18a5-47df-803f-dfa3142f0bd8","order_by":1,"name":"Shen’ao Wang","email":"","orcid":"","institution":"The School of Clinical Medicine, Fujian Medical University","correspondingAuthor":false,"prefix":"","firstName":"Shen’ao","middleName":"","lastName":"Wang","suffix":""},{"id":396376355,"identity":"22304068-1dae-4493-b74d-3bdede0db876","order_by":2,"name":"Weiqiang Wu","email":"","orcid":"","institution":"Fuzhou Second General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Weiqiang","middleName":"","lastName":"Wu","suffix":""},{"id":396376356,"identity":"d49444f3-99ec-4721-8527-a79af6ad9b45","order_by":3,"name":"Xiayu Huang","email":"","orcid":"","institution":"The School of Clinical Medicine, Fujian Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xiayu","middleName":"","lastName":"Huang","suffix":""},{"id":396376357,"identity":"738444c3-290d-4f44-8a9e-a7f1fb70454a","order_by":4,"name":"Binbin Jin","email":"","orcid":"","institution":"Fujian University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Binbin","middleName":"","lastName":"Jin","suffix":""},{"id":396376358,"identity":"e5aee5c2-e647-4a24-ac82-4e2be6c252c2","order_by":5,"name":"Fengfei Lin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAy0lEQVRIiWNgGAWjYBAC+/bm459/VNgwM7Y3EKnFgOdYGjPDmTR25p4DxGqRyFFjZmw7xM8+I4FILeYSOWyPC84ckOad+XjjDYYam2iCWix73h43nlFxx1hydlqxBcOxtNwGgnqO5yVI8Jx5lmw4O8dMgrHhMBFaDuQYSPC2Ha7ff/MMkVoMTuSYSQO1MDPO4CFSi2TPsWTDGWfSmBl7gH5JIMYv/OzNBx98AEfl4Y03PtTYEOEXZEdKJJCiHKKFVB2jYBSMglEwMgAANctFa8z/xPQAAAAASUVORK5CYII=","orcid":"","institution":"Fuzhou Second General Hospital","correspondingAuthor":true,"prefix":"","firstName":"Fengfei","middleName":"","lastName":"Lin","suffix":""},{"id":396376359,"identity":"1c6ec0f2-097f-485b-8717-fb17427ee8e3","order_by":6,"name":"Renbin Li","email":"","orcid":"","institution":"Fuzhou Second General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Renbin","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2024-12-28 14:08:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5726545/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5726545/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":72898042,"identity":"504f465a-77e8-45ca-a3a6-f804eedf1ce0","added_by":"auto","created_at":"2025-01-03 12:12:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":67886,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eGeometric Modeling of Three Different Internal Fixation Methods for Distal Humeral Shaft Fractures.(A) Posterolateral locked plate fixation model. (B) Intramedullary nail + reconstruction plate fixation model. (C) Double reconstruction plate fixation model\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5726545/v1/8245606a888aaa581ce3d853.png"},{"id":72898323,"identity":"2fae36bd-b01c-448e-ad7e-fa7cd0619cb1","added_by":"auto","created_at":"2025-01-03 12:20:33","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":123925,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStress and Displacement Cloud Maps of Different Fixation Models under Axial Compression\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5726545/v1/10b861943ba308d62b9bd4d0.png"},{"id":72898324,"identity":"b3074f52-e210-4648-81ab-162af29d6136","added_by":"auto","created_at":"2025-01-03 12:20:34","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":132772,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStress and Displacement Cloud Maps of Different Fixation Models under Torsional Loading\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5726545/v1/6b43e7dfec532522ae6beaf5.png"},{"id":72898040,"identity":"a7944d3f-d249-4a14-94d1-4aa8496efe35","added_by":"auto","created_at":"2025-01-03 12:12:33","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":131170,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStress and Displacement Cloud Maps of Different Fixation Models under Three-Point Bending\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-5726545/v1/6b5b89b88515426af98820f2.png"},{"id":72899500,"identity":"f38a5636-5e58-4881-8b04-55383093a2e8","added_by":"auto","created_at":"2025-01-03 12:28:33","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":567329,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe patient was a 46-year-old male who sustained a right upper arm injury caused by a fall. Preoperative anteroposterior and lateral X-rays of the right humerus (Figures A, B) revealed a distal-third humeral shaft fracture with a wedge-shaped fragment on the medial side. AO classification: 12B2. On the fourth day after injury, surgical fixation was performed using a humeral intramedullary nail combined with an anterior minimally invasive plate. Postoperative anteroposterior and lateral X-rays (Figures C, D, E) confirmed satisfactory fracture alignment and fixation. At 10 weeks after surgery, functional recovery and incision healing were assessed (Figures F, G, H, I). The internal fixation was removed 15 months after surgery (Figure J).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-5726545/v1/ed8ad4067c5dadf658fcc5b4.png"},{"id":75303307,"identity":"92605f64-ffb9-4744-a5e0-5704dcf2adff","added_by":"auto","created_at":"2025-02-03 08:02:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2575659,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5726545/v1/fd3db9ef-e5de-4c41-9d1d-dbb7c8780a51.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Biomechanical comparison of a hybrid fixation technique with traditional methods for distal humeral shaft fractures: a finite element analysis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDistal humeral shaft fractures commonly occur at the transition between the distal triangular and proximal cylindrical bone shapes, a region prone to mechanical weakness\u003csup\u003e[\u003c/sup\u003e.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e Traditional surgical interventions such as posterolateral plating are widely adopted but carry risks, including extensive soft tissue disruption and potential iatrogenic radial nerve injury. Double plate fixation offers enhanced torsional stability but may exacerbate these complications.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e Alternatively, minimally invasive anterior plating reduces soft tissue damage but is limited by the distal fragment\u0026rsquo;s small size and insufficient fixation strength.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eTo address these challenges, a novel hybrid method combining an intramedullary nail (IMN) with an anterior reconstruction plate (RP) has been proposed. This method minimizes soft tissue damage and reduces the risk of radial nerve injury, achieving favorable clinical outcomes.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e In this study, finite element analysis (FEA) was employed to compare the biomechanical properties of three fixation methods\u0026mdash;posterolateral plating, double reconstruction plating, and IMN\u0026thinsp;+\u0026thinsp;RP\u0026mdash;under different loading conditions. The goal is to provide evidence for optimizing surgical techniques for distal humeral shaft fractures.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Subjects\u003c/h2\u003e \u003cp\u003eA healthy 37-year-old male volunteer (175 cm, 75 kg) with no history of humeral disease, trauma, or osteoporosis was selected. X-ray examination confirmed the absence of old fractures, bone tumors, or other pathologies such as trabecular bone reduction or cortical bone thinning. Thin-slice CT scanning (SINOVISION Insitum CT 768, 128-slice) was performed to acquire high-resolution images of the entire humerus. The CT data were saved in standard DICOM format and used for subsequent 3D modeling. This study was approved by the Ethics Committee of the Fuzhou Second General Hospital (Approval No. 2022086), and informed consent was obtained.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eConstruction of the Humerus 3D Mode\u003c/h3\u003e\n\u003cp\u003eThe DICOM files were imported into Mimics 21.0 (Materialise, Belgium) for image segmentation and geometric modeling of the humerus. Noise reduction and selective segmentation defined the boundaries of bone and soft tissue, generating an STL file of the humeral shaft. The STL file was imported into Geomagic Studio 12.0 (Raindrop Geomagic, USA) for optimization, including smoothing irregular surfaces and eliminating self-intersecting areas. A smooth surface was fitted to create a continuous solid model. To simulate an A-type fracture, a 1 cm-wide gap was introduced at the distal humerus.\u003c/p\u003e\n\u003ch3\u003eFracture and Internal Fixation Models\u003c/h3\u003e\n\u003cp\u003eThe optimized humeral shaft model was imported into Siemens NX (Siemens, Germany) to simulate anatomical reduction and construct three internal fixation models: Posterolateral Locked Plate (Group A): Plate thickness 4.5 mm; screw diameter 3.5 mm (Zheng Tian, Tian Jin ). Intramedullary Nail\u0026thinsp;+\u0026thinsp;Reconstruction Plate (Group B): Nail diameter 7 mm, length 285 mm; plate thickness 3 mm; screw diameter 3.5 mm (Zheng Tian, Tian Jin ). Double Reconstruction Plate (Group C): Two plates with a thickness of 3 mm; screw diameter 3.5 mm (Zheng Tian, Tian Jin ).These fixation models were assembled with the humeral shaft to complete the 3D finite element models for the distal humeral shaft fractures(Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eMaterial Properties\u003c/h3\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eMaterial Assumptions:\u003c/h2\u003e \u003cp\u003eBone and implants were modeled as isotropic, homogeneous, and linear elastic materials. The humerus was simplified as cortical bone to analyze static stress distribution under quasi-static loading. Material properties were assigned based on literature values (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMaterial Properties of the Models\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaterial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eElastic Modulus\u003c/p\u003e \u003cp\u003e(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePoisson\u0026rsquo;s Ratio\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYield Strength\u003c/p\u003e \u003cp\u003e(MPa)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBone Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInternal Fixation\u003c/p\u003e \u003cp\u003e(Nail, Plate, Screws)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e110000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e860\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBoundary Conditions and Load Scenarios:\u003c/h2\u003e \u003cp\u003eThree loading conditions were simulated:Axial Compression: A 200 N load was applied at the distal end while the proximal humerus was fixed.Internal Rotation Torque: A 30 Nm torque was applied at the distal end with the proximal humerus fixed.Three-Point Bending: The proximal and distal ends of the humerus were fixed, and a 30 N load was applied posterior-to-anterior at the fracture site of the distal humerus, simulating a posterior impact on the upper arm.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMeshing:\u003c/h3\u003e\n\u003cp\u003eAdaptive meshing was applied with a grid size of 0.8 mm at implant interfaces and 3 mm for other regions of the humerus. The total node and element counts for each model are detailed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNodes and Elements for Each Model.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNodes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eElements\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e68524\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e314471\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e146997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e684115\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e57043\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e256995\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u003cb\u003eNote\u003c/b\u003e:\u003cb\u003eGroup A: Posterolateral locked plate fixation model.Group B: Intramedullary nail\u0026thinsp;+\u0026thinsp;reconstruction plate fixation model.Group C: Double reconstruction plate fixation model.\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eAxial Compression\u003c/h2\u003e \u003cp\u003eUnder axial compression, the displacement and maximum stress values differed across the three groups Group C (Double Reconstruction Plates) exhibited the least displacement, indicating superior stability under compressive loads. However, Group B (Intramedullary Nail\u0026thinsp;+\u0026thinsp;Reconstruction Plate) displayed slightly higher displacement but achieved a more balanced stress distribution, effectively reducing the risk of stress concentration at the implant interface. In contrast, Group A (Posterolateral Locked Plate) exhibited the highest displacement and stress values, reflecting poor stability under compressive loads(Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eInternal Rotation Torque\u003c/h2\u003e \u003cp\u003eUnder a 30 Nm internal rotation torque, Group B demonstrated the lowest displacement (2.791 mm) and stress values (860.30 MPa), indicating enhanced torsional stability. Group C performed adequately, with slightly higher displacement (5.698 mm) and localized stress concentrations near the distal screws, potentially increasing the risk of fatigue failure. Group A displayed the weakest performance, with the highest displacement (21.830 mm) and stress (1065.45 MPa), highlighting its limited torsional stability(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eThree-Point Bending\u003c/h2\u003e \u003cp\u003eIn three-point bending simulations, Group B showed the lowest displacement (0.022 mm) and stress values (16.56 MPa), demonstrating superior resistance to bending forces. Group C exhibited moderate performance, with slightly higher displacement (0.028 mm) and stress concentrations localized along the proximal plate. Group A showed the weakest bending resistance, with the highest displacement (0.032 mm) and stress values (17.31 MPa) concentrated at the fracture gap(Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eSummary of Biomechanical Findings\u003c/h2\u003e \u003cp\u003eOverall, Group B (Intramedullary Nail\u0026thinsp;+\u0026thinsp;Reconstruction Plate) demonstrated the best biomechanical performance, with consistent stability and uniform stress distribution across all loading conditions. Group C (Double Reconstruction Plates) showed strong compressive resistance but exhibited localized stress concentrations under certain scenarios. Group A (Posterolateral Locked Plate) performed the weakest, with significant stress concentrations and poor stability across all tests (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMaximum Stress, Maximum Displacement, and Stiffness of Three Internal Fixation Models under Axial Compression, Torsion, and Bending\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eAxial Compression\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eTorsion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eThree-Point Bending\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003eStiffness\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Stress(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMax Displacement(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMax Stress(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax Displacement(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMax Stress(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMax Displacement(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eCompression\u003c/p\u003e \u003cp\u003e(N/mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eTorsion\u003c/p\u003e \u003cp\u003e(Nm/\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eThree-Point Bending\u003c/p\u003e \u003cp\u003e(N/mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e344.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.739\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1065.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e21.830\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e17.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e779.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e999.99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroupB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.415\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e860.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.791\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e16.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6033.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e5.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1322.94\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroupC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e72.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.338\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e936.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5.698\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e18.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.028\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e7567.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1152.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eMain Findings\u003c/h2\u003e \u003cp\u003eThis study demonstrated the superior biomechanical performance of the IMN\u0026thinsp;+\u0026thinsp;RP technique for distal humeral shaft fractures. The technique consistently exhibited lower displacement and balanced stress distribution under all loading conditions, effectively addressing the mechanical challenges of these fractures. By minimizing stress concentrations and maintaining robust fixation strength, this approach reduces implant failure risks and improves clinical outcomes.\u003c/p\u003e \u003cp\u003ePosterolateral locked plates, while widely used, exhibit significant displacement and stress concentration at the fracture gap, compromising stability.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003eCompared to traditional methods, double reconstruction plates provide excellent compressive resistance but are associated with extensive soft tissue dissection and a higher risk of iatrogenic radial nerve injury.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003eIn contrast, the IMN\u0026thinsp;+\u0026thinsp;RP technique balances stress distribution and addresses these limitations, offering a robust and innovative solution for managing complex distal humeral shaft fractures.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eClinical Implications\u003c/h2\u003e \u003cp\u003eThe IMN\u0026thinsp;+\u0026thinsp;RP technique offers significant clinical advantages. By preserving vascularity and minimizing soft tissue dissection, it reduces the risks of infection and delayed union. Additionally, the anterior minimally invasive plating decreases the likelihood of radial nerve injury, a common complication associated with traditional methods.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e These biomechanical and clinical benefits support earlier postoperative rehabilitation and better functional recovery for patients with distal humeral shaft fractures.\u003c/p\u003e \u003cp\u003eIn our clinical practice, this technique was applied to treat 40 patients with distal humeral shaft fractures. No cases of iatrogenic radial nerve injury or fracture nonunion were observed. At the final follow-up, the shoulder joint's Constant score averaged 82.77, while the Mayo Elbow Performance Score averaged 90.5, demonstrating excellent functional outcomes(Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and Limitations\u003c/h2\u003e \u003cp\u003eA major strength of this study is the integration of finite element analysis with clinical insights, enabling a comprehensive evaluation of fixation methods under diverse loading scenarios. However, this study is not without limitations. The finite element models did not account for biological factors, such as bone remodeling and soft tissue recovery, that influence fracture healing. Additionally, the simulated loading conditions may not fully replicate dynamic forces encountered during daily activities. Future studies should incorporate in vivo validations and long-term clinical outcomes to enhance the generalizability of these findings.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe intramedullary nail combined with a reconstruction plate (IMN + RP) demonstrated superior biomechanical performance compared to posterolateral locked plating and double reconstruction plating for distal humeral shaft fractures. By achieving enhanced stability and balanced stress distribution, the IMN + RP technique provides a minimally invasive and effective alternative for managing complex distal humeral fractures. Further clinical validation and dynamic loading studies are warranted to confirm its long-term efficacy and safety.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eClinical trial number:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e：\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors had full access to the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Conceptualization, Renbin Li and Fengfei Lin; methodology,Gang Fu and Weiqiang Wu；investigation,Gang Fu,Shen’ao Wang，Xiayu Huang and Binbin Jin; formal analysis,Shen’ao Wang, Weiqiang Wu，Xiayu Huang and Binbin Jin; writing-original draft,Gang Fu and Shen’ao Wang; writing-review and editing, Fengfei Lin and Renbin Li; supervision, Renbin Li;funding acquisition, Fengfei Lin and Renbin Li.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was funded Program for\u0026nbsp;Fujian Provincial Clinical Medical Research Center for First Aid and Rehabilitation in Orthopaedic Trauma (2020Y2014);The Science and Technology Planning Project of Fuzhou (2022-S-053)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInstitutional Review Board approval was received from the ethics committee of Fuzhou second hospital (2022086) and all consents were signed to participate and publish.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll presentations of case reports have consent for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKaradeniz E, Demiroz S, Oktem F, Memisoglu K, Kesemenli CC. Humeral fractures sustained during arm wrestling. Eur J Trauma Emerg Surg. 2022 Aug;48(4):3109-3114. doi: 10.1007/s00068-021-01852-4.\u003c/li\u003e\n\u003cli\u003eOgawa K, Yoshida A, Matsumura N, Inokuchi W. Fractures of the humeral shaft caused by arm wrestling: a systematic review. JSES Rev Rep Tech. 2022 Jun 22;2(4):505-512. doi: 10.1016/j.xrrt.2022.05.005. \u003c/li\u003e\n\u003cli\u003eSharaby, M., \u0026amp; Elhawary, A. (2012). A simple technique for double plating of extraarticular distal humeral shaft fractures. \u003cem\u003eActa orthopaedica Belgica\u003c/em\u003e, \u003cem\u003e78\u003c/em\u003e(6), 708\u0026ndash;713. \u003c/li\u003e\n\u003cli\u003eWu X, Ye Y, Zhu Y, Lin Y, Zhang G, Zhuang Y, Xu Y, Tu S. Modified medial approach for the treatment of fractures of the lower third of the humeral shaft: An anatomical study. Injury. 2024 Dec;55(12):111933. doi: 10.1016/j.injury.2024.111933. \u003c/li\u003e\n\u003cli\u003eWestrick E, Hamilton B, Toogood P, Henley B, Firoozabadi R. Humeral shaft fractures: results of operative and non-operative treatment. Int Orthop. 2017 Feb;41(2):385-395. doi: 10.1007/s00264-016-3210-7.\u003c/li\u003e\n\u003cli\u003eFu G, Zhang Y, Ke S, Zhu D, Wu J, Su D, Ge H, Chen J, Mb YZ, Lin F, Chen J, Li R. Treatment of Distal Third Humeral Shaft Fracture with Intramedullary Nail Combined with Anterior Minimally Invasive Plate Osteosynthesis. Orthop Surg. 2023 Dec;15(12):3101-3107. doi: 10.1111/os.13893. \u003c/li\u003e\n\u003cli\u003eCa\u0026ntilde;ada-Oya H, Ca\u0026ntilde;ada-Oya S, Zarzuela-Jim\u0026eacute;nez C, Delgado-Martinez AD. New, Minimally Invasive, Anteromedial-Distal Approach for Plate Osteosynthesis of Distal-Third Humeral Shaft Fractures: An Anatomical Study. JB JS Open Access. 2020 Mar 12;5(1):e0056. doi: 10.2106/JBJS.OA.19.00056. \u003c/li\u003e\n\u003cli\u003ePastor T, Zderic I, van Knegsel KP, Beeres FJP, Migliorini F, Babst R, Nebelung S, Ganse B, Schoeneberg C, Gueorguiev B, Knobe M. Biomechanical analysis of helical versus straight plating of proximal third humeral shaft fractures. Arch Orthop Trauma Surg. 2023 Aug;143(8):4983-4991. doi: 10.1007/s00402-023-04814-0. \u003c/li\u003e\n\u003cli\u003eSaha MK, Islam SS, Alam S, Rahman MW, Kamruzzaman M, Paul J, Rahman MM, Alamgir MK. Evaluation of Fixation for Distal Humeral Diaphyseal Fracture by Locking Compression Plate. Mymensingh Med J. 2019 Jan;28(1):60-69. \u003c/li\u003e\n\u003cli\u003eAn Z, Zeng B, He X, Chen Q, Hu S. Plating osteosynthesis of mid-distal humeral shaft fractures: minimally invasive versus conventional open reduction technique. Int Orthop. 2010 Feb;34(1):131-5. doi: 10.1007/s00264-009-0753-x. \u003c/li\u003e\n\u003cli\u003eContreras JJ, Soto D, Valencia M, L\u0026oacute;pez M, D\u0026iacute;az A, Delgado S, Lu CY, Mu\u0026ntilde;oz M, Cort\u0026eacute;s F, D\u0026iacute;az C, Beltr\u0026aacute;n M. Treatment of distal third humeral shaft fractures with posterior minimally invasive plate osteosynthesis (MIPO) with segmental isolation of the radial nerve: minimum one-year follow-up. JSES Rev Rep Tech. 2023 Sep 30;4(1):53-60. doi: 10.1016/j.xrrt.2023.08.006. \u003c/li\u003e\n\u003cli\u003eEntezari V, Olson JJ, Vallier HA. Predictors of traumatic nerve injury and nerve recovery following humeral shaft fracture. J Shoulder Elbow Surg. 2021 Dec;30(12):2711-2719. doi: 10.1016/j.jse.2021.04.025. \u003c/li\u003e\n\u003cli\u003eShimamoto Y, Tokutake K, Takegami Y, Asami Y, Sato K, Ueno H, Nakano T, Fujii S, Okui N, Imagama S. Comparative Outcomes of Anterior and Posterior Plating for Distal-Third Humerus Shaft Fractures. J Hand Surg Am. 2023 Sep 7:S0363-5023(23)00389-1. doi: 10.1016/j.jhsa.2023.07.014. \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":"Finite element analysis, Humeral shaft fractures, Intramedullary nail, Biomechanical, Stress peak, Displacement peak","lastPublishedDoi":"10.21203/rs.3.rs-5726545/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5726545/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDistal humeral shaft fractures pose significant challenges in orthopedic surgery due to their complex anatomy and biomechanical demands. Traditional fixation methods, such as posterolateral locked plating and double reconstruction plating, have limitations, including radial nerve injury risk and insufficient stability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study evaluates the biomechanical performance of a hybrid technique combining an intramedullary nail (IMN) with a reconstruction plate (RP) for managing distal humeral shaft fractures.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFinite element analysis (FEA) was conducted to compare the biomechanical properties of IMN + RP, posterolateral locked plating, and double reconstruction plating under axial compression, torsional loading, and bending forces. Key outcomes included displacement, stress distribution, and overall stability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe IMN + RP technique demonstrated superior biomechanical performance, achieving lower displacement and more balanced stress distribution across all loading conditions. It outperformed traditional methods in minimizing stress concentrations and maintaining fixation stability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study highlights the biomechanical superiority of the IMN + RP technique, providing robust evidence for its application in managing distal humeral shaft fractures. These findings contribute to the understanding of hybrid fixation strategies and support further clinical and experimental validation.\u003c/p\u003e","manuscriptTitle":"Biomechanical comparison of a hybrid fixation technique with traditional methods for distal humeral shaft fractures: a finite element analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-03 12:12:28","doi":"10.21203/rs.3.rs-5726545/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":"7fcaf42a-f91d-4b65-83ed-5d096d3f836b","owner":[],"postedDate":"January 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-03T07:54:06+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-03 12:12:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5726545","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5726545","identity":"rs-5726545","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}