Biomechanical Comparative Study of a Novel Proximal Femoral Bionic System for the Treatment of Basal Femoral Neck Fractures: Finite Element Analysis

Biomechanical Comparative Study of a Novel Proximal Femoral Bionic System for the Treatment of Basal Femoral Neck Fractures: 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 Comparative Study of a Novel Proximal Femoral Bionic System for the Treatment of Basal Femoral Neck Fractures: Finite Element Analysis En Wu, Haitao Liu, Feng Gu, Chao Yan, Ting Liu, Bingbing Chen, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8057823/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective: Currently, there is still a lack of in - depth comparative evaluation regarding the biomechanical performance of novel proximal bionic systems in basalfemoral neck fractures (BFNF). This study aims to utilize finite element analysis to compare the mechanical performance differences between two novel proximal bionic systems and traditional PFNA (Proximal Femoral Nail Antirotation) and DHS + DS (Dynamic Hip Screw + Anti - rotation Screw) in the fixation of BFNF. Methods: Based on a validated finite element analysis model, this study constructed an accurate BFNF model and implanted one extramedullary internal fixation device and three intramedullary nail devices: DHS + DS, PFNA, the "second - generation" PFBN (Proximal Femoral Bionic Nail, "II" PFBN), and PFTBN (Proximal Femoral Total Bionic Nail). Under the same vertical load of 2100 N and the same boundary conditions, the displacement and Von Mises stress (VMS) distribution of the BFNF models with different fixation methods were evaluated using the finite element analysis method. Results: When the four devices were used to fix the fracture models under a vertical load of 2100 N, PFTBN showed the best performance in terms of displacement and peak stress, while DHS + DS performed relatively poorly. The mechanical performance of the "II" PFBN was lower than that of PFNA and DHS + DS, and the peak stress and displacement of the PFNA nail were lower than those of DHS + DS. Conclusion: PFTBN demonstrates superior biomechanical stability in the treatment of BFNF, which can reduce the risk of post - operative internal fixation failure. From a biomechanical perspective, the structural designs of the "II" PFBN and PFTBN are more in line with the mechanical conduction characteristics of the femoral neck base, enabling better reconstruction of local mechanical balance and creating a more stable mechanical environment for fracture healing. Therefore, both the "II" PFBN and PFTBN are reliable internal fixation devices for the treatment of BFNF and have potential clinical application prospects. Basal femoral neck fractures Proximal Femoral Nail Antirotation "II"Proximal femoral bionic nails Proximal Femoral Total Bionic Nail Finite element analysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Basal basalfemoral neck fractures (BFNF) involve a fracture line that traverses the base of the femoral neck and its junction with the intertrochanteric region, accounting for approximately 1.8% to 7.7% of all hip fractures [ 1 – 3 ]. Compared to intertrochanteric fractures, BFNF exhibits a larger fracture angle. Moreover, due to the anatomical location of the fracture line, the proximal fragment of the basalfracture has no muscle attachment. Unlike intertrochanteric fractures, there is a lack of trabecular bone interdigitation between the fracture fragments. Consequently, basalfemoral neck fractures are more unstable than intertrochanteric fractures [ 4 ]. In clinical practice, early and rigid internal fixation for BFNF is a widely accepted principle, which facilitates early ambulation and rehabilitation for patients, thereby reducing the risk of bed-related complications such as pressure ulcers, pneumonia, and deep vein thrombosis [ 5 ]. However, literature reports indicate that the failure rate of internal fixation for BFNF remains as high as 15% to 40% [ 6 ]. Since the stability of the internal fixation device directly influences fracture healing outcomes and the incidence of post-operative complications, optimizing the treatment strategy for BFNF remains one of the significant challenges in clinical orthopedic trauma. Currently, various internal fixation devices have been developed for the surgical treatment of BFNF, including dynamic hip screws (DHS + DS), cannulated compression screws (CCS), and proximal femoral nail antirotation (PFNA), among others [ 6 , 7 ]. However, CCS are prone to complications such as femoral neck shortening, screw withdrawal, or cutting in clinical applications [ 8 ]. Although DHS combined with an anti-rotation screw (DHS + DS) offers superior anti-rotation and anti-shear properties compared to CCS, it is associated with greater surgical trauma and is prone to stress concentration due to its longer moment arm, ultimately leading to fixation failure [ 9 ]. PFNA, a commonly used single-headed intramedullary nail system in clinical practice, still faces issues such as insufficient anti-rotation force at the proximal fracture fragment, loosening, or breakage of the head-neck screw, which are critical factors contributing to the clinical failure of intramedullary nail devices [ 10 ]. To address the structural deficiencies of traditional intramedullary nails, scholars have developed two novel proximal femoral bionic systems: the "II" PFBN and PFTBN. Although previous studies have confirmed that traditional intramedullary nail devices exhibit superior biomechanical performance compared to purely extramedullary internal fixation devices, comparative biomechanical studies on the treatment of BFNF using novel intramedullary and traditional extramedullary devices remain scarce, making it difficult to provide sufficient evidence for surgical decision-making by orthopedic surgeons. Finite element analysis (FEA), a numerical analysis method that approximates real physical systems through mathematical simulations, has been widely applied in the biomechanical evaluation and prognostic prediction of orthopedic diseases, injury types, internal fixation devices, and surgical techniques [ 10 ]. Against this backdrop, the core objective of this study is to systematically compare the biomechanical differences among four devices—DHS + DS, PFNA, the "II" PFBN, and PFTBN—in the treatment of BFNF. By evaluating the Von Mises stress (VMS) and displacement of bone and internal fixation devices through FEA, this study aims to provide a scientific biomechanical reference for selecting clinical treatment strategies for patients with BFNF. 2. Materials and Methods 2.1 Establishment of Three-Dimensional Models of the Femur and Internal Fixation Devices In this study, a healthy male volunteer aged 45 years and weighing 67 kg, with no prior history of hip joint diseases or systemic conditions, was recruited for the experiment. The left femur of the volunteer underwent high-precision scanning using a Sensation 64 spiral computed tomography (CT) scanner manufactured by Siemens Medical Solutions in Forchheim, Germany. To ensure high resolution and accuracy of the data, the scan slice thickness was precisely set at 0.625 mm, and the raw scan data were saved in Digital Imaging and Communications in Medicine (DICOM) format. Subsequently, the research team processed the raw CT data using Mimics 21.0 software from Materialise in Leuven, Belgium, successfully constructing a three-dimensional (3D) model of the femur. The model was then refined using Geomagic Studio 13.0 software from Geomagic in the United States, which involved removing surface pores and spikes, refining the surface mesh, and ultimately achieving a surface-rendered femur model. During the smoothing process, the original curvature of the target regions was strictly adhered to, ensuring that the macroscopic features of the model were fully preserved. The optimized model was then imported into 3-matic software to prepare for subsequent simulation analyses. To ensure research precision, the research team employed a manual segmentation method to accurately define the cortical and trabecular bone regions in the CT images. The region 2 mm inward from the bone surface (a thickness based on actual measurements from the CT images) was defined as cortical bone, while the remaining internal region was defined as trabecular bone. Subsequently, the Adaptive remesh function was used to mesh the internal fixation devices and bone models, with all structures utilizing 1 mm-sized elements to ensure simulation accuracy. In Hypermesh software, surface meshes were imported, and solid meshes were generated. According to the simulation requirements, the meshes of both the bone and intramedullary fixation devices were refined into C3D4 tetrahedral elements. Additionally, the research team utilized UG-NX 12.0 software from Siemens Product Lifecycle Management Software Inc. in the United States to precisely construct models of DHS + DS, PFNA, the second-generation PFBN, and PFTBN (Figs. 1 and 2 ). Simultaneously, a BFNF model was also established using the same software, designed according to the latest 2018 AO/OTA classification standard [ 11 ]. The main fracture line (classified as 31-B3) of this model was located at the base of the femoral neck, making a 70° angle with the horizontal plane, a setting that closely aligns with clinical and lays a solid foundation for subsequent simulation analyses. In the experiment, the research team also employed four different internal fixation devices to stabilize the model (Fig. 2 ). 2.2 Material Properties In this study, the material properties of the femur and internal fixation devices were set to be uniformly distributed, isotropic, and exhibiting linear elastic behavior. Specifically, all four types of internal fixation devices were primarily composed of titanium alloy. Drawing on parameter configurations from previous similar studies [ 12 , 13 , 14 ], the elastic modulus of cortical bone was determined to be 16.8 GPa, while that of trabecular bone was set at 0.58 GPa. Additionally, the Poisson's ratios for both cortical and trabecular bone were uniformly valued at 0.3. For the internal fixation devices, the elastic modulus was established at 110 GPa, with a Poisson's ratio of 0.31. Detailed material parameter information for each component can be found in the following table (Table 1 ). 2.3 Boundary Conditions and Load Settings During the course of this study, surface contact settings were uniformly applied to three types of contact relationships: bone-bone interface, bone-screw, and screw-screw. A frictional contact model was selected to realistically simulate actual conditions. In terms of specific parameter settings, when bones came into contact with each other, the friction coefficient was set at 0.46. For bone-screw contact, the friction coefficient was established at 0.42, while for screw-screw contact, it was set at 0.2.Regarding boundary condition settings, all degrees of freedom at the distal end of the femoral model were fully constrained to ensure that no unnecessary displacements occurred during the simulation process. Simultaneously, the region where the femoral head contacts the pelvis was coupled to a concentrated point. A precise force was then applied at this point to simulate the vertically downward force experienced by the human body during normal standing. The magnitude of this load was set at 2100N. 2.4 Model Validation To ensure the accuracy of our research findings, we constructed a comprehensive femoral fracture model and developed four types of internal fixation device models. Following the methods outlined in references [ 15 , 16 ], we appropriately assigned corresponding material properties to these models. Subsequently, we fully constrained the degrees of freedom at the distal end of the femoral model to maintain its stability during the simulation process. Meanwhile, a vertical load of 2100N was applied at a specific concentrated point on the femoral head to simulate the actual force experienced by the human body.Using the advanced Ansys 19.0 finite element analysis software (developed by ANSYS Inc. in the United States), we conducted in-depth and meticulous analyses of the aforementioned models. After completing the analyses, we rigorously and carefully compared the obtained results with the data reported in references [ 15 , 16 ]. The comparison revealed a high degree of consistency between the two sets of data, which fully validated the effectiveness and reliability of the models we constructed. 2.5 Main Evaluation Parameters In this study, ANSYS Workbench 2020 R2 software (ANSYS, Canonsburg, PA, USA) was used to analyze in detail the biomechanical properties of the proximal and distal regions of the femur and the four different internal fixation devices. The main output parameters for evaluation included the von Mises stress distribution maps, displacement distribution maps, and corresponding distribution data of the four internal fixation devices, the femur, and the fracture end. These data provided strong support for the comparative analysis of the mechanical characteristics among the four internal fixation models. Table 1 Material parameters Materials Elastic modulus(GPa) Poisson's ratio Cortical bone 16.8 0.3 Cancellous bone 0.58 0.3 Head of femur 0.9 0.29 Collum femoris 0.62 0.29 Internal fixation device 110 0.31 3. Results 3.1 Von Mises Stress Distribution of the Four Internal Fixation Devices 3.1.1 Stress on the Main Nail and Lateral Plate The DHS + DS group exhibited the highest stress (64.784 MPa), while the "II" PFBN group showed the lowest (32.824 MPa). The PFNA group had a stress of 51.975 MPa, and the PFTBN group had 38.192 MPa. Stress on the main nail and lateral plate is a crucial factor contributing to the fatigue failure of internal fixation components. The "II" PFBN group had the lowest stress on the main nail, indicating a more reasonable design of the main nail structure and stronger anti-fatigue capability. In contrast, the DHS + DS group had high stress on the fixation plate, which is prone to loosening and fracture of the screw-plate assembly (Fig. 3 ). 3.1.2 Stress on the Compression Screw The DHS + DS group had the highest stress (116.53 MPa), while the "II" PFBN group had the lowest (87.716 MPa). The PFNA group had a stress of 115.45 MPa, and the PFTBN group had 98.367 MPa. Stress on the compression screw is closely related to the anti-cutting and anti-pullout capabilities of the internal fixation device. The "II" PFBN group had low stress on the helical blade, indicating more stable fixation within the femoral head and a lower risk of cutting and pullout. In contrast, the DHS + DS group had high stress, posing a greater risk of compression screw failure(Fig. 3 ). 3.1.3 Overall Stress on the Internal Fixation Device The DHS + DS group had the highest overall stress (138.484 MPa), with the maximum stress located at the lag screw. The "II" PFBN group had the lowest overall stress (87.716 MPa). The PFNA group had a stress of 115.45 MPa, and the PFTBN group had 98.367 MPa. The overall stress distribution of the internal fixation device comprehensively reflects the mechanical performance of the internal fixation system. The "II" PFBN group had the lowest overall stress, indicating the best system stability. However, the PFTBN device had a more dispersed distribution of peak overall stress. The DHS + DS group had high overall stress, making the internal fixation system prone to fatigue fracture and other failures(Fig. 3 ). 3.2 Von Mises Stress Distribution of the Femur 3.2.1 Stress on the Femoral Head The DHS + DS group had the highest stress (290.49 MPa), while the PFTBN group had the lowest (218.51 MPa). The PFNA group had a stress of 252.16 MPa, and the "II" PFBN group had 236.35 MPa. Excessive stress on the femoral head can lead to complications such as avascular necrosis. The PFTBN group had the lowest stress on the femoral head, reducing the risk of such complications. The high stress in the DHS + DS group is related to the mechanical characteristic of stress concentration in the femoral head region(Fig. 4 ). 3.2.2 Stress on the Femoral Shaft The DHS + DS group had the highest stress (305.07 MPa), followed by the "II" PFBN group (242.59 MPa). The PFNA group had a stress of 280.91 MPa, and the PFTBN group had 235.27 MPa. The stress distribution on the femoral shaft reflects the stress conduction effect of the internal fixation on the femoral shaft. The PFTBN and "II" PFBN groups had lower stress on the femoral shaft, indicating more uniform stress conduction and reduced local stress concentration on the femoral shaft. The high stress on the femoral shaft in the DHS + DS group can induce problems such as femoral shaft fractures(Fig. 4 ). 3.3 Displacement Distribution of the Four Intramedullary Nail Devices The DHS + DS group had the largest peak displacement (5.0329 mm), while the PFTBN group had the smallest (4.6828 mm). The PFNA group had a displacement of 4.9354 mm, and the "II" PFBN group had 4.806 mm. The smaller the deformation of the internal fixation device, the stronger its resistance to deformation. The PFTBN group had the smallest deformation of the internal fixation, indicating a more favorable structural design for stress dispersion and effective control of its own deformation. The large deformation of the internal fixation in the DHS + DS group is related to the characteristic of stress concentration in the screw-plate structure. Among these four internal fixation devices, the PFTBN device exhibited the lowest peak displacement, indicating better structural stability under load and a reduced risk of screw fracture under the same load. In contrast, the DHS + DS device showed the highest peak displacement, suggesting a higher likelihood of internal fixation failure under the same load conditions (Fig. 5 ). 3.4 Displacement Distribution of the Entire Femur 3.4.1 Deformation of the Femoral Head The DHS + DS group had the largest peak displacement (5.1789 mm), while the PFTBN group had the smallest (4.839 mm). The PFNA group had a displacement of 5.1364 mm, and the "II" PFBN group had 5.0323 mm. In terms of deformation, the PFTBN group provided the best support and restraint for the femoral head. The DHS + DS group showed the most significant deformation of the femoral head due to its mechanical conduction path characteristics (Fig. 5 ). 3.4.2 Deformation at the Fracture Site The DHS + DS group had the largest peak displacement at the fracture site (0.5043 mm), while the PFTBN group had the smallest (0.35862 mm). The PFNA group had a displacement of 0.412 mm, and the "II" PFBN group had 0.37361 mm. Deformation at the fracture site directly affects the stability of fracture healing. Smaller deformation leads to closer contact at the fracture site, which is beneficial for callus growth. The PFTBN and "II" PFBN groups had small deformation at the fracture site, providing better stability for fracture fixation. In contrast, the DHS + DS group had relatively insufficient stability (Fig. 5 ). 4. Discussion For femoral neck fractures in young and middle-aged adults, internal fixation techniques remain the preferred standard treatment in most cases. However, disruption of blood supply and unstable fixation of the femoral head are the primary risk factors leading to post-operative non-union and necrosis of the femoral head [ 17 ]. Currently, surgeons tend to prefer extramedullary fixation techniques, such as cannulated compression screws (CCS) and dynamic hip screws (DHS), when treating unstable femoral neck fractures (UFNFs) [ 18 , 19 ]. Studies have shown that adding an additional cortical bone pull-out screw (DHS + DS) to the DHS can enhance its anti-rotation performance, but complications such as post-operative femoral neck shortening and coxa vara have drawn widespread attention. These issues arise due to abductor muscle weakness and limited hip sub-function, resulting in a reduced abductor lever arm. Additionally, post-operative femoral neck shortening following femoral neck fracture surgery further increases the risk of femoral head collapse [ 20 ]. Therefore, improving the overall stability of femoral neck fracture devices and developing dedicated intramedullary fixation devices for femoral neck fractures have become current research hotspots. Although the proximal femoral nail anti-rotation (PFNA) generates less bending moment on the implant, helping to prevent further collapse at the fracture site and reducing bone loss compared to DHS, its efficacy in treating basic femoral neck fractures (BFNF) remains suboptimal [ 21 ]. Röderer et al. investigated the application of the proximal femoral nail anti-rotation device (PFNA) in unstable femoral neck fractures and found that PFNA could rival the stability of the dynamic hip screw blade (DHS), indicating the potential of intramedullary nail fixation techniques in treating femoral neck fractures [ 22 ]. However, PFNA, which contains only one helical blade, is more prone to proximal screw reverse migration, proximal femoral shortening, and a reduction in the proximal femoral varus angle [ 23 ]. When treating unstable hip fractures in elderly patients, PFNA has a mechanical failure rate of 7.5%, encompassing a range of complications such as implant cut-out occurring at a rate between 5.4–13%, coxa vara at 2.5%, and internal fixation failure at 1% [ 24 , 25 ]. Consequently, research teams have dedicated efforts to designing two improved intramedullary nail fixation devices to more effectively stabilize proximal femoral fractures. Through in-depth research on complications associated with internal fixation devices, scholars such as Zhang proposed that mechanical failures often stem from a mismatch between the internal fixation device and the anatomical structure and mechanical dynamic properties of the proximal femur. Adopting a triangular stable structure might effectively reduce the risk of failure in intramedullary nail fixation devices, a theory that has propelled the development of the proximal femoral bionic nail (PFBN) technology [ 28 ]. The uniqueness of PFBN lies in its dual-triangle design, composed of a support screw, fixation screw, and main nail, precisely simulating the mechanical properties of the normal proximal femoral cantilever beam structure. In this design, the fixation screw is doubly supported by the main nail and the support screw, forming a dual-pivot fixation mode that effectively shortens the lever arm, significantly reduces stress concentration, and thereby substantially enhances post-operative stability in femoral neck fractures. Building on the success of the first-generation PFBN, the research team meticulously crafted the second-generation PFBN. The core improvement in this upgrade involves further advancing the intersection point of the pull-out screw and the transverse screw, an optimization that further strengthens the fixation effect of the internal fixator, enhancing fracture fixation robustness while further mitigating stress shielding effects [ 29 ]. However, the specific role of the "II"PFBN in providing lateral wall support for BFNF remains unclear. To overcome this limitation, scholars have proposed the PFTBN internal fixation device [ 30 ]. The innovation of this device lies in the placement of an anchoring screw from the tail of the pressure screw of the "first-generation" PFBN to below the lesser trochanter, enhancing the original femoral lateral wall's resistance to the varus trend of the head-neck screw and improving the lateral wall's lever resistance. In this study, we employed finite element analysis technology to comprehensively evaluate the biomechanical performance of DHS + DS, PFNA, "II"PFBN, and PFTBN in treating BFNF. The results revealed that PFTBN significantly enhanced overall stability when fixing BFNF compared to the DHS + DS, PFNA, and "II"PFBN models. Furthermore, PFTBN exhibited lower stress peaks and more favorable stress distribution in the proximal femoral region than DHS + DS and PFNA, demonstrating superior resistance to load and shear forces. Although its peak stress was slightly higher than that of PFBN, its stress distribution was more dispersed, reducing the risk of internal fixation device failure due to stress concentration. These characteristics may be crucial factors contributing to its improved clinical efficacy in treating BFNF. From the perspective of displacement distribution, the fracture end stability and overall structural stability of the PFTBN model were superior to those of the DHS + DS, PFNA, and "II"PFBN models, further confirming PFTBN's outstanding performance in resisting load and shear forces. We analyze that the support screw in PFTBN plays a pivotal role in reducing stress concentration on the fixation screw, helping to lower the risks of screw loosening, fracture, and coxa vara. For elderly patients, especially those often suffering from osteoporosis, PFTBN may offer better stability and support for early post-operative rehabilitation training. However, it should be noted that this study has not delved deeply into the mechanical properties of PFTBN and "II"PFBN in osteoporosis models. The material parameter settings of the models differ from actual bone characteristics, and the experimental load settings did not fully account for muscle group effects. Future research will further expand the range of fracture types and internal fixation devices selected, enhancing model accuracy and experimental complexity to better guide clinical practice and optimize the design of intramedullary nail devices. 5. Conclusion When treating basic femoral neck fractures, the PFTBN demonstrates significant advantages in terms of femoral head deformation, internal fixation device deformation, and stress dispersion at multiple sites. The "II" PFBN performs outstandingly in controlling stress on the femoral shaft and the main nail. Both may be more promising internal fixation device options for basic femoral neck fractures. In particular, the PFTBN exhibits superior biomechanical stability in terms of multi-dimensional mechanical properties, which can reduce the risk of postoperative internal fixation failure. From a biomechanical perspective, the structural designs of the "II" PFBN and the PFTBN are more in line with the mechanical conduction characteristics of the base of the femoral neck, enabling better reconstruction of local mechanical balance and creating a more stable mechanical environment for fracture healing. Declarations Ethics approval and methods declarations Ethical approval for this study was obtained from the Medical Human Experimental Ethics Committee of Aerospace Center Hospital, all methods were performed in accordance with the relevant guidelines and regulations Consent to participate All patients signed a written informed consent before recruitment. Consent for publication All authors listed meet the authorship criteria according to the guidelines of the International Committee of Medical Journal Editors. All authors are in agreement with the manuscript. Availability of data and material The datasets used and analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding 1. Aerospace Medicine Translational Medicine: Research and Development of Surgical Robot-Assisted New Intramedullary Nail for Distal Radius Fracture and Its Biomechanical Study (2023YK24) 2. Aerospace Medicine Translational Medicine: Research and Development and Application of the Third-Generation Minimally Invasive Three-Dimensional Guided Instrument for Hallux Valgus (2024YK14) References Fan X, Zhou Y, Dai S, Lao K, Zhang Q, Yu T. Bio-mechanical effects of femoral neck system versus cannulated screws on treating young patients with Pauwels type III femoral neck fractures: a finite element analysis. BMC Musculoskelet Disord. 2024;25(1):83. Published 2024 Jan 20. 10.1186/s12891-023-07110–5 Tang Z, Zhu Z, Lv Y et al. 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Injury. 2014;45(10):1624–31. 10.1016/j.injury.2014.06.002 . Rupprecht M, Grossterlinden L, Sellenschloh K, et al. Internal fixation of femoral neck fractures with posterior comminution: a biomechanical comparison of DHS® and Intertan nail®. Int Orthop. 2011;35(11):1695–701. 10.1007/s00264-010-1199-x . Wang Z, Yang Y, Feng G et al. Biomechanical comparison of the femoral neck system versus InterTan nail and three cannulated screws for unstable Pauwels type III femoral neck fracture. Biomed Eng Online. 2022;21(1):34. Published 2022 Jun 10. 10.1186/s12938-022-01006–6 Wang Y, Chen W, Zhang L, et al. Finite Element Analysis of Proximal Femur Bionic Nail (PFBN) Compared with Proximal Femoral Nail Antirotation and InterTan in Treatment of Intertrochanteric Fractures. Orthop Surg. 2022;14(9):2245–55. 10.1111/os.13247 . Wang Q, Lu Y, Liu L et al. Finite element analysis of the modified intramedullary nail-II for managing reverse obliquity trochanteric fractures. Sci Rep. 2025;15(1):21303. Published 2025 Jul 1. 10.1038/s41598-025-05748-w Chen X, Tang M, Zhang X, et al. A Novel Internal Fixation Design for the Treatment of AO/OTA–31A3.3 Intertrochanteric Fractures: Finite Element Analysis. Orthop Surg. 2024;16(7):1684–94. 10.1111/os.14041 . 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-8057823","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":550383964,"identity":"e68dc7b2-0ec6-4dc6-981a-34b82b0e4b59","order_by":0,"name":"En Wu","email":"","orcid":"","institution":"Aerospace Center Hospital","correspondingAuthor":false,"prefix":"","firstName":"En","middleName":"","lastName":"Wu","suffix":""},{"id":550383965,"identity":"0913868d-ee99-4bda-8075-ac7b66f3b3c2","order_by":1,"name":"Haitao Liu","email":"","orcid":"","institution":"Aerospace Center 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03:23:35","extension":"html","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":100249,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/95e388eb58c5c1af99187bb4.html"},{"id":96870312,"identity":"40310c64-6746-44d8-810e-d4631cc90c44","added_by":"auto","created_at":"2025-11-27 03:23:34","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":67377,"visible":true,"origin":"","legend":"\u003cp\u003eIn the \"II\" PFBN , component \u003cstrong\u003ea\u003c/strong\u003e is the main nail, \u003cstrong\u003eb \u003c/strong\u003eis the compression screw, \u003cstrong\u003ec\u003c/strong\u003e is the tension screw, which is perpendicular to the main nail, \u003cstrong\u003ed\u003c/strong\u003eis the pull-out screw, \u003cstrong\u003ee\u003c/strong\u003e is the distal locking screw,and \u003cstrong\u003ef \u003c/strong\u003eis the fulcrum for both the pressure screw and the pull-out screw. Compared to the first-generation PFBN, the advancement of this fulcrum forward optimizes the mechanical performance.. In the PFTBN , component \u003cstrong\u003ea \u003c/strong\u003eis the main nail, \u003cstrong\u003eb \u003c/strong\u003eis the compression screw,\u003cstrong\u003e c \u003c/strong\u003eis the tension screw, which is perpendicular to the main nail, \u003cstrong\u003ed\u003c/strong\u003eis the lateral wall screw, placed from the lateral side of the greater trochanter, and \u003cstrong\u003ee \u003c/strong\u003eis the distal locking screw.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/9a842691e949b0ea6f04f161.jpeg"},{"id":96919312,"identity":"17bf1cb0-582f-463f-89e1-f00508bbe2e1","added_by":"auto","created_at":"2025-11-27 14:13:34","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":70341,"visible":true,"origin":"","legend":"\u003cp\u003eA shows the three-dimensional models of four internal fixation devices, namely DHS+DS , PFNA, \"II\" PFBN , and PFTBN ; B shows the three-dimensional models of femoral neck base fractures equipped with the four internal fixations.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/4efc3455e1f4d04e6f8575db.jpeg"},{"id":96870339,"identity":"936e3d70-02a4-4493-a6e8-dd83d5cdf5c2","added_by":"auto","created_at":"2025-11-27 03:23:35","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":11923842,"visible":true,"origin":"","legend":"\u003cp\u003eStress distribution diagrams of four new internal fixation devices for the fixation of femoral neck base fractures. (A, E, I) Stress distribution diagrams of the DHS+DS device; (B, F, J) Stress distribution diagrams of the PFNA device; (C, G, K) Stress distribution diagrams of the \"II\" PFBN device; (D, H, L) Stress distribution diagrams of the PFTBN device.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/56f73e17aaaf5929692cd4b5.jpeg"},{"id":96870305,"identity":"8f613707-6b7f-4fc3-9468-9a56ce81eba3","added_by":"auto","created_at":"2025-11-27 03:23:33","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":12561779,"visible":true,"origin":"","legend":"\u003cp\u003eFemoral stress distribution diagrams of femoral neck base fractures fixed with four new internal fixation devices. (A, E, I) Femoral stress distribution diagrams fixed with the DHS+DS device; (B, F, J) Femoral stress distribution diagrams fixed with the PFNA device; (C, G, K) Femoral stress distribution diagrams fixed with the \"II\" PFBN device; (D, H, L) Femoral stress distribution diagrams fixed with the PFTBN device.\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/37b1fe2b6a032b75ce4e7077.jpeg"},{"id":96870365,"identity":"b5c9244f-c12a-4897-9053-71354086b9db","added_by":"auto","created_at":"2025-11-27 03:23:37","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":11784393,"visible":true,"origin":"","legend":"\u003cp\u003eDisplacement distribution diagrams of femoral neck base fractures fixed with four new internal fixation devices. (A, E, I) Displacement distribution diagrams of the femur and fracture surfaces fixed with the DHS+DS device; (B, F, J) Displacement distribution diagrams of the femur and fracture surfaces fixed with the PFNA device; (C, G, K) Displacement distribution diagrams of the femur and fracture surfaces fixed with the \"Generation II\" PFBN device; (D, H, L) Displacement distribution diagrams of the femur and fracture surfaces fixed with the PFTBN device.\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/79d5045c83c5a148c0846a63.jpeg"},{"id":98623336,"identity":"32c617db-ea18-4037-9d64-3e2e0301fb24","added_by":"auto","created_at":"2025-12-19 17:05:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":37221374,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8057823/v1/cbee4e41-cc33-49fc-95fb-1d3790a24126.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Biomechanical Comparative Study of a Novel Proximal Femoral Bionic System for the Treatment of Basal Femoral Neck Fractures: Finite Element Analysis","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eBasal basalfemoral neck fractures (BFNF) involve a fracture line that traverses the base of the femoral neck and its junction with the intertrochanteric region, accounting for approximately 1.8% to 7.7% of all hip fractures [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Compared to intertrochanteric fractures, BFNF exhibits a larger fracture angle. Moreover, due to the anatomical location of the fracture line, the proximal fragment of the basalfracture has no muscle attachment. Unlike intertrochanteric fractures, there is a lack of trabecular bone interdigitation between the fracture fragments. Consequently, basalfemoral neck fractures are more unstable than intertrochanteric fractures [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In clinical practice, early and rigid internal fixation for BFNF is a widely accepted principle, which facilitates early ambulation and rehabilitation for patients, thereby reducing the risk of bed-related complications such as pressure ulcers, pneumonia, and deep vein thrombosis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, literature reports indicate that the failure rate of internal fixation for BFNF remains as high as 15% to 40% [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Since the stability of the internal fixation device directly influences fracture healing outcomes and the incidence of post-operative complications, optimizing the treatment strategy for BFNF remains one of the significant challenges in clinical orthopedic trauma.\u003c/p\u003e\u003cp\u003eCurrently, various internal fixation devices have been developed for the surgical treatment of BFNF, including dynamic hip screws (DHS\u0026thinsp;+\u0026thinsp;DS), cannulated compression screws (CCS), and proximal femoral nail antirotation (PFNA), among others [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. However, CCS are prone to complications such as femoral neck shortening, screw withdrawal, or cutting in clinical applications [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Although DHS combined with an anti-rotation screw (DHS\u0026thinsp;+\u0026thinsp;DS) offers superior anti-rotation and anti-shear properties compared to CCS, it is associated with greater surgical trauma and is prone to stress concentration due to its longer moment arm, ultimately leading to fixation failure [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. PFNA, a commonly used single-headed intramedullary nail system in clinical practice, still faces issues such as insufficient anti-rotation force at the proximal fracture fragment, loosening, or breakage of the head-neck screw, which are critical factors contributing to the clinical failure of intramedullary nail devices [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eTo address the structural deficiencies of traditional intramedullary nails, scholars have developed two novel proximal femoral bionic systems: the \"II\" PFBN and PFTBN. Although previous studies have confirmed that traditional intramedullary nail devices exhibit superior biomechanical performance compared to purely extramedullary internal fixation devices, comparative biomechanical studies on the treatment of BFNF using novel intramedullary and traditional extramedullary devices remain scarce, making it difficult to provide sufficient evidence for surgical decision-making by orthopedic surgeons.\u003c/p\u003e\u003cp\u003eFinite element analysis (FEA), a numerical analysis method that approximates real physical systems through mathematical simulations, has been widely applied in the biomechanical evaluation and prognostic prediction of orthopedic diseases, injury types, internal fixation devices, and surgical techniques [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Against this backdrop, the core objective of this study is to systematically compare the biomechanical differences among four devices\u0026mdash;DHS\u0026thinsp;+\u0026thinsp;DS, PFNA, the \"II\" PFBN, and PFTBN\u0026mdash;in the treatment of BFNF. By evaluating the Von Mises stress (VMS) and displacement of bone and internal fixation devices through FEA, this study aims to provide a scientific biomechanical reference for selecting clinical treatment strategies for patients with BFNF.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Establishment of Three-Dimensional Models of the Femur and Internal Fixation Devices\u003c/h2\u003e\u003cp\u003eIn this study, a healthy male volunteer aged 45 years and weighing 67 kg, with no prior history of hip joint diseases or systemic conditions, was recruited for the experiment. The left femur of the volunteer underwent high-precision scanning using a Sensation 64 spiral computed tomography (CT) scanner manufactured by Siemens Medical Solutions in Forchheim, Germany. To ensure high resolution and accuracy of the data, the scan slice thickness was precisely set at 0.625 mm, and the raw scan data were saved in Digital Imaging and Communications in Medicine (DICOM) format.\u003c/p\u003e\u003cp\u003eSubsequently, the research team processed the raw CT data using Mimics 21.0 software from Materialise in Leuven, Belgium, successfully constructing a three-dimensional (3D) model of the femur. The model was then refined using Geomagic Studio 13.0 software from Geomagic in the United States, which involved removing surface pores and spikes, refining the surface mesh, and ultimately achieving a surface-rendered femur model. During the smoothing process, the original curvature of the target regions was strictly adhered to, ensuring that the macroscopic features of the model were fully preserved. The optimized model was then imported into 3-matic software to prepare for subsequent simulation analyses.\u003c/p\u003e\u003cp\u003eTo ensure research precision, the research team employed a manual segmentation method to accurately define the cortical and trabecular bone regions in the CT images. The region 2 mm inward from the bone surface (a thickness based on actual measurements from the CT images) was defined as cortical bone, while the remaining internal region was defined as trabecular bone. Subsequently, the Adaptive remesh function was used to mesh the internal fixation devices and bone models, with all structures utilizing 1 mm-sized elements to ensure simulation accuracy. In Hypermesh software, surface meshes were imported, and solid meshes were generated. According to the simulation requirements, the meshes of both the bone and intramedullary fixation devices were refined into C3D4 tetrahedral elements.\u003c/p\u003e\u003cp\u003eAdditionally, the research team utilized UG-NX 12.0 software from Siemens Product Lifecycle Management Software Inc. in the United States to precisely construct models of DHS\u0026thinsp;+\u0026thinsp;DS, PFNA, the second-generation PFBN, and PFTBN (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Simultaneously, a BFNF model was also established using the same software, designed according to the latest 2018 AO/OTA classification standard [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The main fracture line (classified as 31-B3) of this model was located at the base of the femoral neck, making a 70\u0026deg; angle with the horizontal plane, a setting that closely aligns with clinical and lays a solid foundation for subsequent simulation analyses. In the experiment, the research team also employed four different internal fixation devices to stabilize the model (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Material Properties\u003c/h2\u003e\u003cp\u003eIn this study, the material properties of the femur and internal fixation devices were set to be uniformly distributed, isotropic, and exhibiting linear elastic behavior. Specifically, all four types of internal fixation devices were primarily composed of titanium alloy. Drawing on parameter configurations from previous similar studies [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], the elastic modulus of cortical bone was determined to be 16.8 GPa, while that of trabecular bone was set at 0.58 GPa. Additionally, the Poisson's ratios for both cortical and trabecular bone were uniformly valued at 0.3. For the internal fixation devices, the elastic modulus was established at 110 GPa, with a Poisson's ratio of 0.31. Detailed material parameter information for each component can be found in the following table (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Boundary Conditions and Load Settings\u003c/h2\u003e\u003cp\u003eDuring the course of this study, surface contact settings were uniformly applied to three types of contact relationships: bone-bone interface, bone-screw, and screw-screw. A frictional contact model was selected to realistically simulate actual conditions. In terms of specific parameter settings, when bones came into contact with each other, the friction coefficient was set at 0.46. For bone-screw contact, the friction coefficient was established at 0.42, while for screw-screw contact, it was set at 0.2.Regarding boundary condition settings, all degrees of freedom at the distal end of the femoral model were fully constrained to ensure that no unnecessary displacements occurred during the simulation process. Simultaneously, the region where the femoral head contacts the pelvis was coupled to a concentrated point. A precise force was then applied at this point to simulate the vertically downward force experienced by the human body during normal standing. The magnitude of this load was set at 2100N.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Model Validation\u003c/h2\u003e\u003cp\u003eTo ensure the accuracy of our research findings, we constructed a comprehensive femoral fracture model and developed four types of internal fixation device models. Following the methods outlined in references [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], we appropriately assigned corresponding material properties to these models. Subsequently, we fully constrained the degrees of freedom at the distal end of the femoral model to maintain its stability during the simulation process. Meanwhile, a vertical load of 2100N was applied at a specific concentrated point on the femoral head to simulate the actual force experienced by the human body.Using the advanced Ansys 19.0 finite element analysis software (developed by ANSYS Inc. in the United States), we conducted in-depth and meticulous analyses of the aforementioned models. After completing the analyses, we rigorously and carefully compared the obtained results with the data reported in references [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The comparison revealed a high degree of consistency between the two sets of data, which fully validated the effectiveness and reliability of the models we constructed.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5 Main Evaluation Parameters\u003c/h2\u003e\u003cp\u003eIn this study, ANSYS Workbench 2020 R2 software (ANSYS, Canonsburg, PA, USA) was used to analyze in detail the biomechanical properties of the proximal and distal regions of the femur and the four different internal fixation devices. The main output parameters for evaluation included the von Mises stress distribution maps, displacement distribution maps, and corresponding distribution data of the four internal fixation devices, the femur, and the fracture end. These data provided strong support for the comparative analysis of the mechanical characteristics among the four internal fixation models.\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 parameters\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=\"left\" 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\u003eMaterials\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eElastic modulus(GPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePoisson's ratio\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCortical bone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCancellous bone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHead of femur\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.29\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCollum femoris\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.29\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInternal fixation device\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e110\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.31\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Von Mises Stress Distribution of the Four Internal Fixation Devices\u003c/h2\u003e\u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\u003ch2\u003e3.1.1 Stress on the Main Nail and Lateral Plate\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group exhibited the highest stress (64.784 MPa), while the \"II\" PFBN group showed the lowest (32.824 MPa). The PFNA group had a stress of 51.975 MPa, and the PFTBN group had 38.192 MPa. Stress on the main nail and lateral plate is a crucial factor contributing to the fatigue failure of internal fixation components. The \"II\" PFBN group had the lowest stress on the main nail, indicating a more reasonable design of the main nail structure and stronger anti-fatigue capability. In contrast, the DHS\u0026thinsp;+\u0026thinsp;DS group had high stress on the fixation plate, which is prone to loosening and fracture of the screw-plate assembly (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\u003ch2\u003e3.1.2 Stress on the Compression Screw\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the highest stress (116.53 MPa), while the \"II\" PFBN group had the lowest (87.716 MPa). The PFNA group had a stress of 115.45 MPa, and the PFTBN group had 98.367 MPa. Stress on the compression screw is closely related to the anti-cutting and anti-pullout capabilities of the internal fixation device. The \"II\" PFBN group had low stress on the helical blade, indicating more stable fixation within the femoral head and a lower risk of cutting and pullout. In contrast, the DHS\u0026thinsp;+\u0026thinsp;DS group had high stress, posing a greater risk of compression screw failure(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e3.1.3 Overall Stress on the Internal Fixation Device\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the highest overall stress (138.484 MPa), with the maximum stress located at the lag screw. The \"II\" PFBN group had the lowest overall stress (87.716 MPa). The PFNA group had a stress of 115.45 MPa, and the PFTBN group had 98.367 MPa. The overall stress distribution of the internal fixation device comprehensively reflects the mechanical performance of the internal fixation system. The \"II\" PFBN group had the lowest overall stress, indicating the best system stability. However, the PFTBN device had a more dispersed distribution of peak overall stress. The DHS\u0026thinsp;+\u0026thinsp;DS group had high overall stress, making the internal fixation system prone to fatigue fracture and other failures(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Von Mises Stress Distribution of the Femur\u003c/h2\u003e\u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\u003ch2\u003e3.2.1 Stress on the Femoral Head\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the highest stress (290.49 MPa), while the PFTBN group had the lowest (218.51 MPa). The PFNA group had a stress of 252.16 MPa, and the \"II\" PFBN group had 236.35 MPa. Excessive stress on the femoral head can lead to complications such as avascular necrosis. The PFTBN group had the lowest stress on the femoral head, reducing the risk of such complications. The high stress in the DHS\u0026thinsp;+\u0026thinsp;DS group is related to the mechanical characteristic of stress concentration in the femoral head region(Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\u003ch2\u003e3.2.2 Stress on the Femoral Shaft\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the highest stress (305.07 MPa), followed by the \"II\" PFBN group (242.59 MPa). The PFNA group had a stress of 280.91 MPa, and the PFTBN group had 235.27 MPa. The stress distribution on the femoral shaft reflects the stress conduction effect of the internal fixation on the femoral shaft. The PFTBN and \"II\" PFBN groups had lower stress on the femoral shaft, indicating more uniform stress conduction and reduced local stress concentration on the femoral shaft. The high stress on the femoral shaft in the DHS\u0026thinsp;+\u0026thinsp;DS group can induce problems such as femoral shaft fractures(Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Displacement Distribution of the Four Intramedullary Nail Devices\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the largest peak displacement (5.0329 mm), while the PFTBN group had the smallest (4.6828 mm). The PFNA group had a displacement of 4.9354 mm, and the \"II\" PFBN group had 4.806 mm. The smaller the deformation of the internal fixation device, the stronger its resistance to deformation. The PFTBN group had the smallest deformation of the internal fixation, indicating a more favorable structural design for stress dispersion and effective control of its own deformation. The large deformation of the internal fixation in the DHS\u0026thinsp;+\u0026thinsp;DS group is related to the characteristic of stress concentration in the screw-plate structure.\u003c/p\u003e\u003cp\u003eAmong these four internal fixation devices, the PFTBN device exhibited the lowest peak displacement, indicating better structural stability under load and a reduced risk of screw fracture under the same load. In contrast, the DHS\u0026thinsp;+\u0026thinsp;DS device showed the highest peak displacement, suggesting a higher likelihood of internal fixation failure under the same load conditions (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Displacement Distribution of the Entire Femur\u003c/h2\u003e\u003cdiv id=\"Sec18\" class=\"Section3\"\u003e\u003ch2\u003e3.4.1 Deformation of the Femoral Head\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the largest peak displacement (5.1789 mm), while the PFTBN group had the smallest (4.839 mm). The PFNA group had a displacement of 5.1364 mm, and the \"II\" PFBN group had 5.0323 mm. In terms of deformation, the PFTBN group provided the best support and restraint for the femoral head. The DHS\u0026thinsp;+\u0026thinsp;DS group showed the most significant deformation of the femoral head due to its mechanical conduction path characteristics (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section3\"\u003e\u003ch2\u003e3.4.2 Deformation at the Fracture Site\u003c/h2\u003e\u003cp\u003eThe DHS\u0026thinsp;+\u0026thinsp;DS group had the largest peak displacement at the fracture site (0.5043 mm), while the PFTBN group had the smallest (0.35862 mm). The PFNA group had a displacement of 0.412 mm, and the \"II\" PFBN group had 0.37361 mm. Deformation at the fracture site directly affects the stability of fracture healing. Smaller deformation leads to closer contact at the fracture site, which is beneficial for callus growth. The PFTBN and \"II\" PFBN groups had small deformation at the fracture site, providing better stability for fracture fixation. In contrast, the DHS\u0026thinsp;+\u0026thinsp;DS group had relatively insufficient stability (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eFor femoral neck fractures in young and middle-aged adults, internal fixation techniques remain the preferred standard treatment in most cases. However, disruption of blood supply and unstable fixation of the femoral head are the primary risk factors leading to post-operative non-union and necrosis of the femoral head [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Currently, surgeons tend to prefer extramedullary fixation techniques, such as cannulated compression screws (CCS) and dynamic hip screws (DHS), when treating unstable femoral neck fractures (UFNFs) [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Studies have shown that adding an additional cortical bone pull-out screw (DHS\u0026thinsp;+\u0026thinsp;DS) to the DHS can enhance its anti-rotation performance, but complications such as post-operative femoral neck shortening and coxa vara have drawn widespread attention. These issues arise due to abductor muscle weakness and limited hip sub-function, resulting in a reduced abductor lever arm. Additionally, post-operative femoral neck shortening following femoral neck fracture surgery further increases the risk of femoral head collapse [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Therefore, improving the overall stability of femoral neck fracture devices and developing dedicated intramedullary fixation devices for femoral neck fractures have become current research hotspots.\u003c/p\u003e\u003cp\u003eAlthough the proximal femoral nail anti-rotation (PFNA) generates less bending moment on the implant, helping to prevent further collapse at the fracture site and reducing bone loss compared to DHS, its efficacy in treating basic femoral neck fractures (BFNF) remains suboptimal [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. R\u0026ouml;derer et al. investigated the application of the proximal femoral nail anti-rotation device (PFNA) in unstable femoral neck fractures and found that PFNA could rival the stability of the dynamic hip screw blade (DHS), indicating the potential of intramedullary nail fixation techniques in treating femoral neck fractures [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. However, PFNA, which contains only one helical blade, is more prone to proximal screw reverse migration, proximal femoral shortening, and a reduction in the proximal femoral varus angle [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. When treating unstable hip fractures in elderly patients, PFNA has a mechanical failure rate of 7.5%, encompassing a range of complications such as implant cut-out occurring at a rate between 5.4\u0026ndash;13%, coxa vara at 2.5%, and internal fixation failure at 1% [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Consequently, research teams have dedicated efforts to designing two improved intramedullary nail fixation devices to more effectively stabilize proximal femoral fractures.\u003c/p\u003e\u003cp\u003eThrough in-depth research on complications associated with internal fixation devices, scholars such as Zhang proposed that mechanical failures often stem from a mismatch between the internal fixation device and the anatomical structure and mechanical dynamic properties of the proximal femur. Adopting a triangular stable structure might effectively reduce the risk of failure in intramedullary nail fixation devices, a theory that has propelled the development of the proximal femoral bionic nail (PFBN) technology [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The uniqueness of PFBN lies in its dual-triangle design, composed of a support screw, fixation screw, and main nail, precisely simulating the mechanical properties of the normal proximal femoral cantilever beam structure. In this design, the fixation screw is doubly supported by the main nail and the support screw, forming a dual-pivot fixation mode that effectively shortens the lever arm, significantly reduces stress concentration, and thereby substantially enhances post-operative stability in femoral neck fractures. Building on the success of the first-generation PFBN, the research team meticulously crafted the second-generation PFBN. The core improvement in this upgrade involves further advancing the intersection point of the pull-out screw and the transverse screw, an optimization that further strengthens the fixation effect of the internal fixator, enhancing fracture fixation robustness while further mitigating stress shielding effects [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eHowever, the specific role of the \"II\"PFBN in providing lateral wall support for BFNF remains unclear. To overcome this limitation, scholars have proposed the PFTBN internal fixation device [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The innovation of this device lies in the placement of an anchoring screw from the tail of the pressure screw of the \"first-generation\" PFBN to below the lesser trochanter, enhancing the original femoral lateral wall's resistance to the varus trend of the head-neck screw and improving the lateral wall's lever resistance. In this study, we employed finite element analysis technology to comprehensively evaluate the biomechanical performance of DHS\u0026thinsp;+\u0026thinsp;DS, PFNA, \"II\"PFBN, and PFTBN in treating BFNF. The results revealed that PFTBN significantly enhanced overall stability when fixing BFNF compared to the DHS\u0026thinsp;+\u0026thinsp;DS, PFNA, and \"II\"PFBN models. Furthermore, PFTBN exhibited lower stress peaks and more favorable stress distribution in the proximal femoral region than DHS\u0026thinsp;+\u0026thinsp;DS and PFNA, demonstrating superior resistance to load and shear forces. Although its peak stress was slightly higher than that of PFBN, its stress distribution was more dispersed, reducing the risk of internal fixation device failure due to stress concentration. These characteristics may be crucial factors contributing to its improved clinical efficacy in treating BFNF.\u003c/p\u003e\u003cp\u003eFrom the perspective of displacement distribution, the fracture end stability and overall structural stability of the PFTBN model were superior to those of the DHS\u0026thinsp;+\u0026thinsp;DS, PFNA, and \"II\"PFBN models, further confirming PFTBN's outstanding performance in resisting load and shear forces. We analyze that the support screw in PFTBN plays a pivotal role in reducing stress concentration on the fixation screw, helping to lower the risks of screw loosening, fracture, and coxa vara. For elderly patients, especially those often suffering from osteoporosis, PFTBN may offer better stability and support for early post-operative rehabilitation training.\u003c/p\u003e\u003cp\u003eHowever, it should be noted that this study has not delved deeply into the mechanical properties of PFTBN and \"II\"PFBN in osteoporosis models. The material parameter settings of the models differ from actual bone characteristics, and the experimental load settings did not fully account for muscle group effects. Future research will further expand the range of fracture types and internal fixation devices selected, enhancing model accuracy and experimental complexity to better guide clinical practice and optimize the design of intramedullary nail devices.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eWhen treating basic femoral neck fractures, the PFTBN demonstrates significant advantages in terms of femoral head deformation, internal fixation device deformation, and stress dispersion at multiple sites. The \"II\" PFBN performs outstandingly in controlling stress on the femoral shaft and the main nail. Both may be more promising internal fixation device options for basic femoral neck fractures. In particular, the PFTBN exhibits superior biomechanical stability in terms of multi-dimensional mechanical properties, which can reduce the risk of postoperative internal fixation failure. From a biomechanical perspective, the structural designs of the \"II\" PFBN and the PFTBN are more in line with the mechanical conduction characteristics of the base of the femoral neck, enabling better reconstruction of local mechanical balance and creating a more stable mechanical environment for fracture healing.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and methods declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval for this study was obtained from the Medical Human Experimental Ethics Committee of Aerospace Center Hospital, all methods were performed in accordance with the relevant guidelines and regulations\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll patients signed a written informed consent before recruitment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors listed meet the authorship criteria according to the guidelines of the International Committee of Medical Journal Editors. All authors are in agreement with the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and analyzed 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\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1. Aerospace Medicine Translational Medicine: Research and Development of Surgical Robot-Assisted New Intramedullary Nail for Distal Radius Fracture and Its Biomechanical Study (2023YK24)\u003c/p\u003e\n\u003cp\u003e2. Aerospace Medicine Translational Medicine: Research and Development and Application of the Third-Generation Minimally Invasive Three-Dimensional Guided Instrument for Hallux Valgus (2024YK14)\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFan X, Zhou Y, Dai S, Lao K, Zhang Q, Yu T. Bio-mechanical effects of femoral neck system versus cannulated screws on treating young patients with Pauwels type III femoral neck fractures: a finite element analysis. BMC Musculoskelet Disord. 2024;25(1):83. Published 2024 Jan 20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12891-023-07110\u0026ndash;5\u003c/span\u003e\u003cspan address=\"10.1186/s12891-023-07110\u0026ndash;5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTang Z, Zhu Z, Lv Y et al. 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Published 2022 Jun 10. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12938-022-01006\u0026ndash;6\u003c/span\u003e\u003cspan address=\"10.1186/s12938-022-01006\u0026ndash;6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang Y, Chen W, Zhang L, et al. Finite Element Analysis of Proximal Femur Bionic Nail (PFBN) Compared with Proximal Femoral Nail Antirotation and InterTan in Treatment of Intertrochanteric Fractures. Orthop Surg. 2022;14(9):2245\u0026ndash;55. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/os.13247\u003c/span\u003e\u003cspan address=\"10.1111/os.13247\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang Q, Lu Y, Liu L et al. Finite element analysis of the modified intramedullary nail-II for managing reverse obliquity trochanteric fractures. Sci Rep. 2025;15(1):21303. Published 2025 Jul 1. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/s41598-025-05748-w\u003c/span\u003e\u003cspan address=\"10.1038/s41598-025-05748-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen X, Tang M, Zhang X, et al. A Novel Internal Fixation Design for the Treatment of AO/OTA\u0026ndash;31A3.3 Intertrochanteric Fractures: Finite Element Analysis. Orthop Surg. 2024;16(7):1684\u0026ndash;94. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/os.14041\u003c/span\u003e\u003cspan address=\"10.1111/os.14041\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\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":"Basal femoral neck fractures, Proximal Femoral Nail Antirotation, \"II\"Proximal femoral bionic nails, Proximal Femoral Total Bionic Nail, Finite element analysis","lastPublishedDoi":"10.21203/rs.3.rs-8057823/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8057823/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective: \u003c/strong\u003eCurrently, there is still a lack of in - depth comparative evaluation regarding the biomechanical performance of novel proximal bionic systems in basalfemoral neck fractures (BFNF). This study aims to utilize finite element analysis to compare the mechanical performance differences between two novel proximal bionic systems and traditional PFNA (Proximal Femoral Nail Antirotation) and DHS + DS (Dynamic Hip Screw + Anti - rotation Screw) in the fixation of BFNF.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eBased on a validated finite element analysis model, this study constructed an accurate BFNF model and implanted one extramedullary internal fixation device and three intramedullary nail devices: DHS + DS, PFNA, the \"second - generation\" PFBN (Proximal Femoral Bionic Nail, \"II\" PFBN), and PFTBN (Proximal Femoral Total Bionic Nail). Under the same vertical load of 2100 N and the same boundary conditions, the displacement and Von Mises stress (VMS) distribution of the BFNF models with different fixation methods were evaluated using the finite element analysis method.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eWhen the four devices were used to fix the fracture models under a vertical load of 2100 N, PFTBN showed the best performance in terms of displacement and peak stress, while DHS + DS performed relatively poorly. The mechanical performance of the \"II\" PFBN was lower than that of PFNA and DHS + DS, and the peak stress and displacement of the PFNA nail were lower than those of DHS + DS.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003ePFTBN demonstrates superior biomechanical stability in the treatment of BFNF, which can reduce the risk of post - operative internal fixation failure. From a biomechanical perspective, the structural designs of the \"II\" PFBN and PFTBN are more in line with the mechanical conduction characteristics of the femoral neck base, enabling better reconstruction of local mechanical balance and creating a more stable mechanical environment for fracture healing. Therefore, both the \"II\" PFBN and PFTBN are reliable internal fixation devices for the treatment of BFNF and have potential clinical application prospects.\u003c/p\u003e","manuscriptTitle":"Biomechanical Comparative Study of a Novel Proximal Femoral Bionic System for the Treatment of Basal Femoral Neck Fractures: Finite Element Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-27 03:23:10","doi":"10.21203/rs.3.rs-8057823/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":"434ed8fc-995d-4460-b652-000b1f0c12f6","owner":[],"postedDate":"November 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-18T05:24:16+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-27 03:23:10","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8057823","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8057823","identity":"rs-8057823","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}