Finite Element Analysis of PFNA and PFNA Combined with Locking Plate in Treatment of Femoral Intertrochanteric Fracture with Lateral Wall Fracture

Finite Element Analysis of PFNA and PFNA Combined with Locking Plate in Treatment of Femoral Intertrochanteric Fracture with Lateral Wall Fracture | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Finite Element Analysis of PFNA and PFNA Combined with Locking Plate in Treatment of Femoral Intertrochanteric Fracture with Lateral Wall Fracture Long Zhou, Liang Wang, Rui Xu, Yidong Bao, Shuangjian He This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4588928/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 Purpose: The biomechanical characteristics of Proximal Femoral Nail Antirotation (PFNA) and PFNA combined with Proximal Humerus Locking Plate (PHLP) in treatment of femoral intertrochanteric fracture with lateral wall fracture were compared by finite element analysis, and the biomechanical strength, stress and displacement distribution of the two internal fixation methods were compared. Methods: A healthy middle-aged female patient was selected. According to the femur CT scan data, the three-dimensional finite element models of the femur, PFNA, and PHLP were established .The simulated AO classification was 31-A3.3 femoral intertrochanteric fracture, and the two internal fixation assembly models of PFNA and PNFA+PHLP were established. The von mises stress distribution and displacement distribution nephograms of the two internal fixation models were observed when the same load was applied on the two models under the dynamic and static status. Result: Compared with PFNA fixation, PFNA+PHLP fixation reduced the maximum von mises stress by about 40%, while the maximum displacement changed little. The stress at the fracture end and the main nail position decreased, with a noticeablereduction of about 40% at the main nail. The Von Mises stress of the femoral head, femoral neck, medial, wall and spiral blade changed little. The total displacement of the femoral head, femoral neck, lateral wall, and spiral blade of PFNA+PHLP fixation decreased insignificant. Conclusion: PFNA + PHLP internal fixation in the treatment of femoral intertrochanteric fracture with lateral wall fracture has higher fixation strength and more reasonable stress distribution than PFNA internal fixation. femoral intertrochanteric fracture femoral lateral wall intramedullary nail plate finite element analysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction Femoral intertrochanteric fracture is a common type of hip fracture in the elderly. Although with a high fracture healing rate, the functional effect after the operation is often disappointing. Many patients cannot recover their activity level before the fracture, which is related to their physical condition, fracture type and internal fixation method . [ 1 , 2 ] As the proximal continuation of the femoral diaphysis, the lateral wall is anatomically defined as the horizontal area of the lateral cortex of the proximal femur between the vast lateralis ridge below the apex of the greater trochanter and the plane of the midpoint of the lesser trochanter. [ 3 ] A complete lateral wall provides the necessary support for the proximal bone fragments and the internal fixation spiral blade, which facilitates bone stabilization and reduces internal fixation stress and internal fixation failure rates. [ 4 – 6 ] The lateral wall is also the attachment point of the gluteus medius and gluteus minimus. The hip joint's soft tissue balance and stability will be significantly affected if the lateral wall is ruptured with reduction failure. Therefore, more scholars tend to reconstruct the lateral wall. [ 7 , 8 ] Femoral intertrochanteric fracture with lateral wall fracture is an unstable fracture. Applying PFNA fixation alone on patients is prone to complications such as coxa vara, internal fixation loosening and cutting out, resulting in internal fixation failure. [ 9 , 10 ] Clinically, some scholars attempted to achieve early stability by reconstructing the lateral femoral wall with locking plate, improving the mechanical conduction at proximal femoral and increasing the balance and stability of the soft tissues of hip joint. Through the comparison between the effects of locking plate reconstruction of the lateral wall and PFNA internal fixation, the former method proves to have obvious advantages in the aspects of fracture healing time, weight-bearing exercise time and improvement of hip joint function. [ 11 ] However, there are few reports on biomechanical research of the two internal fixation methods, which leads to the lack of basic data support. In this study, it was further confirmed that PFNA + PHLP had higher fixation strength and more reasonable stress distribution than PFNA internal fixation by analyzing the stress distribution and displacement distribution of internal fixation models under static and dynamic status of two internal fixation models of femoral intertrochanteric fracture with lateral wall fracture constructed by finite element, which provided theoretical support for clinical treatment. Material and methods Femoral CT data The target was a 57-year-old female volunteer, weight being 60kg, having no history of medical and surgical diseases, no limbs disability and trauma history. A 64-slice spiral CT was used to scan the bone tissue windows of bilateral upper femur, the scanning layer being 1mm in thickness, interval of 1 mm, ranging from 10cm above the vertex of greater trochanter to the plane of knee joint. The scanning data were saved in DICOM format and the data of the right femur were used as the specimen. Experimental software Mimics Research 21.0, Geomagic Wrap, HyperMesh 2019, Creo 6.0, Abaqus 2020 were applied for data analysis and image processing. Construction of A3.3 type Femoral Intertrochanteric Fracture Model Import the CT image data of the volunteer into Mimics Research 21.0, select the default threshold set “Bone (CT)” to identify the femur and then make the three-dimensional reconstruction of the right femur by Edit Masks, Smart Fill, Calculate Part, and Smooth. Following that, import the three-dimensional reconstruction into Geomagic Wrap in STL format, construct the A3.3 type femoral intertrochanteric fracture model by remeshing, deleting, and filling holes, and form the three parts of femoral head and neck bone, lesser trochanter bone, and femoral shaft bone (Fig. 1 A). In the end, optimize the model by using the fitting surface and other operations, and save it in the format of STEP. Building of PFNA Internal Fixation Model and PFNA + PHLP Internal Fixation Model 3D modeling and assembly were carried out in Creo 6.0 to obtain PFNA, PHLP and PFNA + PHLP models (Fig. 1 B). Orthotropic cross-sectional views of the PFNA internal fixation were obtained by defining the cross-section (Fig. 1 C). The specifics of the internal fixation are shown in Table 1 . Accemble the A3.3 type femoral intertrochanteric fracture model, the PFNA model, and the PFNA + PHLP model under the surgical standards in Abaqus 2020, ensuring that the positive position of spiral blade being in the 1/3 middle and lower position of the femoral neck, the lateral position of spiral blade being in the center of the femoral neck, with the tip-apex distance less than 20 mm, the locking plate located in the lateral side of the femur. In order to facilitate finite element modeling assembly, we opened a hole in the middle part of the plate through the steps of cutting geometry, geometric editing and the like and then conduct model combination. Simulate a self-locking nail for locking the plate by using commands such as coupling, binding and the like to carry out unicortical fixation on femur with three screws on the top and bottom. Import the model into HyperMesh 2019 in STEP format for meshing, using C3D10M as the element type, with the size of 2 mm, and its grid convergence was verified. Export the model in INP format to obtain the PFNA internal fixation assembly model (Fig. 1 D) and PFNA + PHLP internal fixation assembly model (Fig. 1 E). The friction coefficient between bone was 0.46,the friction coefficient between bone and internal fixation was 0.3, and the friction coefficient between the spiral blade and the main nail was 0.23 [ 12 ] . Table 1 Details of internal fixation. Materials Models and specifications Manufacturers PFNA 170 mm in the length of the main nail; 10 mm in the diameter of the spiral blade, 100 mm in length; 130⁰ in the collo-diaphyseal angle of the femur, and 5⁰ in the femoral valgus resection angle. Suzhou Xinrong Best Medical Instrument Co., Ltd. PHLP Three-hole plate with a length of 95 mm Ideal (Suzhou) Medical Instrument Co., Ltd. Define Material Properties and Boundary Conditions Import the file of femoral mesh model of A3.3 type femoral intertrochanteric fracture into Mimics Research 21.0 in INP format, and divide the model into 10 materials according to the gray value. According to the empirical formula provided by Mimics: Density = − 13.4 + 1017 * Gray value, Young's modulus = − 388.8 + 5925 * Density. Poisson's ratio was 0.3, complete the assignment of femoral material propertie. Then import the file into Abaqus 2020 software in INP format. The material parameters of the internal fixation model were set as follows: Young's modulus was 110 GPa, with a Poisson's ratio of 0.3. [ 13 , 14 ] The boundary conditions were all set as follows: the distal femur was completely fixed,the reference point was selected on the sphericity of the femoral head and defined as RP-1, and this point was coupled with some nodes of the sphericity of the femoral head. According to the body weight of volunteers, the z-direction load of 100% body weight(600 N) and 285% body weight (1710 N) were applied to the reference point (Fig. 2 ) to simulate the static load on the femur and the maximum dynamic load when walking at a speed of 4km/h. [ 15 ] Submit Calculation and Result Analysis After completing the above processing, select the Abaqus/Standard solver,set the running kernel and the memory, and submit the solution calculation. Mainly calculate the Von Mises stress and displacement distribution of two internal fixation models. Flollowing that, view and analyze the calculation results in Abaqus 2020 software. Results According to the analysis of the Von Mises stress nephogram (Fig. 3 ) and displacement nephogram (Fig. 4 ) of the two internal fixation models, the maximum Von Mises stress of PFNA internal fixation model and PFNA + PHLP internal fixation model was 264.4Mpa and 152.1Mpa under static state, respectively, and the latter was reduced by about 40%. The maximum Von Mises stress of the former was located at the contact position of the spiral blade and the main nail, while that of the latter was near the junction of the plate and the spiral blade tail end. The stress distribution in the femoral was more uniform with PFNA + PHLP internal fixation than with PFNA internal fixation.The maximum displacement of the two models were located at the top of the sphericity of the femoral head, with the value of 1.548mm of the former and 1.395mm of the latter. Under dynamic state, the maximum Von Mises stress of PFNA internal fixation model and PFNA + PHLP internal fixation model was 774.9Mpa and 446.5Mpa, respectively, with the latter decreased by about 40%. The locations of the maximum Von Mises stress and displacement were consistent with those under static load. The maximum displacement was 5.688mm in the former and 5.115mm in the latter. The above data are summarized in Table 2 . Compared with PFNA fixation, PFNA + PHLP fixation reduced the stress at the fracture end (including femoral head end, corpora femoris end and lesser trochanter end) and the main nail, especially at the main nail. The main nail’s Von Mises stress of PFNA fixation and PFNA + PHLP fixation was 15.09Mpa and 9.03Mpa respectively in static state, and 45.35Mpa and 26.98Mpa respectively in dynamic state, which were reduced by about 40%. Little change was seen on the Von Mises stress of the femoral head, femoral neck, medial wall and spiral blade of PFNA + PHLP fixation (Fig. 5 ). Compared with PFNA fixation, the overall displacement of femoral head, femoral neck, lateral wall and spiral blade of PFNA + PHLP fixation were reduced in both static and dynamic state, but didn’t vary too much (Fig. 6 ). Table 2 The Von Mises stress and displacement of the two internal fixation methods under dynamic and static state. Internal fixation methods The Von Mises stress under static state(Mpa) The Von Mises stress under dynamic state(Mpa) The displacement under static state(mm) The displacement under dynamic state(mm) PFNA 264.4 774.9 1.548 5.688 PFNA + PHLP 152.1 446.5 1.395 5.115 Discussion Von rüden et al. considered the joint of the main nail and the spiral blade to be the main stress concentration area and the weak point of the head and neck type intramedullary nail. [ 16 ] In this study, it was found that the maximum Von Mises stress of PFNA fixation occurs at the contact position of spiral blade and main nail, while that of PFNA + PHLP fixation was near the junction of the plate and the spiral blade tail end, and that of PFNA + PHLP fixation decreased by about 40% under static and dynamic state. The change of the position of the maximum Von Mises stress and the reduction of the stress value avoided the internal fixation failure caused by the stress concentration. Regarding the femoral intertrochanteric fracture with lateral wall fracture, Wang Renkai et al. proposed the five-point stability theory, which believed that the head end of the spiral blade, the main nail at the entrance of the greater trochanter, the proximal end of the lateral wall fracture, the distal end of the lateral wall fracture, and the distal locking nail formed a stable frame structure. And the lateral plate connecting the proximal end and the distal end of the femur enhanced the stability of the fracture end. [ 17 ] Compared with PFNA fixation, the Von Mises stress of main nail of PFNA + PHLP fixation was reduced by about 40% under both dynamic and static load, and the Von Mises stress of the lateral wall was increased in the same condition, which was realated to the use of the plate and nail to fix the lateral wall. The Von Mises stress of the plate in the static state was 11.77Mpa, and 34.76Mpa in the dynamic state, taking away more stress off the main nail, thus making the stress distribution of the whole internal fixation system more reasonable. The decline of the stress at the fractured end further proves that the reconstruction of the lateral wall by PHLP could enhance the stability of the internal fixation, which was consistent with the five-point stability theory proposed by Wang Renkai et al, while the stress the femoral head, femoral neck, medial wall and spiral blade took did not change much. According to the displacement nephogram, the maximum displacements of the two internal fixations were located at the top of the sphericity of femoral head, and there was no significant difference between static and dynamic states. When using PHLP to fix the lateral wall, the displacement of femoral head, femoral neck, lateral wall and spiral blade were also reduced, but not greatly. It indicated that there was little effect on the displacement when reconstructing the lateral wall by PHLP, and it obviously improved the stress distribution and fixation strength. PFNA intramedullary fixation has always been considered as the high standard for internal fixation of femoral intertrochanteric fracture surgery due to its unique biomechanical and minimally invasive advantages, and the main nail can serve as the metal lateral wall, which can reduce the migration of bone mass to a certain extent. [ 18 , 19 ] However, internal fixation failure still exists when using PFNA method, especially in unstable fracture types with lateral wall fracture. [ 20 , 21 ] For unstable femoral intertrochanteric fractures with rupture lateral wall, especially type A3.3, scholars advocate reconstruction of the lateral wall in Stage I, and the use of nails, Kirschner wires, tension band, and plate to reconstruct the lateral wall according to different types of lateral wall fracture. It has a definite effect on clinical treatments, but lacks data supporting of basic theoretical research. [ 22 – 24 ] Internal fixation with steel plate was preferred for severe damage of lateral wall, considering the similarity between the structures of the proximal femur and the proximal humerus, we did not routinely select a narrow reconstruction locking plate to be placed anterolateral to the proximal femur, but creatively used PHLP to fix the lateral wall because of the larger width of PHLP, which could fix the lateral wall in a wider range. We also collected some clinical cases, found that PFNA + PHLP internal fixation took a little longer operation time and had a little more bleeding than PFNA internal fixation, while the incidence of complications such as varus of the hip and the time of rehabilitation and exercise in the ground had obvious advantages. It could better improve the function of hip joint and enhance the surgical effect. However, the data sample size is not big enough, and more clinical cases will continue to be collected for retrospective study. In this paper, the common AO 31-A3.3 type femoral intertrochanteric fracture in clinic was taken as the research object, and the Von Mises stress distribution and displacement distribution of PFNA internal fixation and PFNA + PHLP internal fixation under dynamic and static load were compared by finite element analysis for the first time, providing further theoretical data support for clinical treatment. In summary, we conclude that PFNA + PHLP internal fixation in treatment of femoral intertrochanteric fracture with lateral wall fracture has higher fixation strength and more reasonable stress distribution than PFNA internal fixation, which can allow patients to recover functional exercises and walking ability earlier after surgery, reduce complications and improve their quality of life. Of course, there are still some shortcomings in this experiment. The maximum load of the human walking was simulated by applying a constant load, but in fact, the human walking gait is a very complex process, which presents the gait cycle load. At the same time, the hip joint reaction force and the surrounding muscle force should be considered. The bone mineral density and elastic modulus of the femur in this experiment were deduced according to the empirical formula provided by Mimics, which might be different from the actual situation. Only a typical fracture type was studied. Subsequently, the finite element analysis of the hip joint under walking condition will be further optimized, and the comparison of fracture models with different bone mineral density and elastic modulus will be perfected to better guide the surgical internal fixation plan for the clinical treatment of femoral intertrochanteric fracture with lateral wall fracture. Abbreviations PFNA Proximal Femoral Nail Antirotation PHLP Proximal Humerus Locking Plate Declarations Acknowledgements None Authors’ contributions LZ and SJH conceived and designed the study. YDB and RX built the finite element model. LZ and RX analyzed the data. SJH and LWL revised the article. All authors read and approved the final manuscript. Funding This work was supported by grants from the Clinical Key Diseases’ Diagnosis and Treatment of Suzhou (LCZX202135) and the Research Program of Suzhou Science and Technology (SKY2023117). Availability of data and materials Almost all data generated or analysed during this study are included in this published article. The datasets used and/or analysed during the current study available from the corresponding author on reasonable request. Ethics approval and consent to participate The study was approved by the ethics committee of Suzhou Hospital, Affiliated Hospital of Medical School, Nanjing University. Signing the informed consent was waived by the ethics committee of Suzhou Hospital, Affiliated Hospital of Medical School, Nanjing University. Consent for publication Not applicable. Competing interests The authors declare no competing interests. References Lisk R, Yeong K. Reducing mortality from hip fractures: a systematic quality improvement programme. BMJ Qual Improv Rep. 2014;3(1):u205006w2103. Buyukdogan K, Caglar O, Isik S, Tokgozoglu M, Atilla B. Risk factors for cut-out of double lag screw fixation in proximal femoral fractures. Injury. 2017;48(2):414–8. Ma Z, Chang S-m. Letter to the editor: where is the lateral femoral wall? Int Orthop. 2014;38(12):2645–6. Palm H, Jacobsen S, Sonne-Holm S, Gebuhr P. Integrity of the lateral femoral wall in intertrochanteric hip fractures: an important predictor of a reoperation. J Bone Joint Surg Am. 2007;89(3):470–5. Hsu CE, Shih CM, Wang CC, Huang KC. Lateral femoral wall thickness. 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Augmentation of proximal femoral nail in unstable trochanteric fractures. Sicot j. 2017;3:12. Imerci A, Aydogan NH, Tosun K. The effect on outcomes of the application of circumferential cerclage cable following intramedullary nailing in reverse intertrochanteric femoral fractures. Eur J Orthop Surg Traumatol. 2019;29(4):835–42. 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4588928","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":317505345,"identity":"48daae0f-f9a7-44bd-bc8c-5c210af674ac","order_by":0,"name":"Long Zhou","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYDCCAwyMB0C0AQMD44OEChuitDDAtDAbPDiTRpoWNsmHbYcI6+C7fYDhwMcdtfbm7D1mFQlsBxj427sT8GqRPJfAcHDmmePMlj1nzG4k8NxhkDhzdgNeLQZnGBgO87YdYzO4kQPUIvGMwUAilzgtPCAtBQkGh4nWUiMB0sKQkECEFkmgloMz2w4YGJw5ViyRcCCNh6Bf+M4AY/BjW529wfHmjR9//rOR42/vxa+FgYH/A5A4DOfyEFAOB3XEKhwFo2AUjIKRCAA0Wk5BsNoHfgAAAABJRU5ErkJggg==","orcid":"","institution":"Suzhou Hospital, Nanjing University","correspondingAuthor":true,"prefix":"","firstName":"Long","middleName":"","lastName":"Zhou","suffix":""},{"id":317505347,"identity":"81b60a7b-69be-46ba-9629-c7d460f17525","order_by":1,"name":"Liang Wang","email":"","orcid":"","institution":"Suzhou Hospital, Nanjing University","correspondingAuthor":false,"prefix":"","firstName":"Liang","middleName":"","lastName":"Wang","suffix":""},{"id":317505349,"identity":"2254f3d1-52b1-458d-a2eb-b9adf0cb11be","order_by":2,"name":"Rui Xu","email":"","orcid":"","institution":"Nanjing University of Aeronautics and Astronautics","correspondingAuthor":false,"prefix":"","firstName":"Rui","middleName":"","lastName":"Xu","suffix":""},{"id":317505351,"identity":"b7160e05-8684-4037-a410-126f18e0e94e","order_by":3,"name":"Yidong Bao","email":"","orcid":"","institution":"Nanjing University of Aeronautics and Astronautics","correspondingAuthor":false,"prefix":"","firstName":"Yidong","middleName":"","lastName":"Bao","suffix":""},{"id":317505353,"identity":"efcc8425-0f99-4e35-a124-06ce41f1f732","order_by":4,"name":"Shuangjian He","email":"","orcid":"","institution":"Suzhou Hospital, Nanjing University","correspondingAuthor":false,"prefix":"","firstName":"Shuangjian","middleName":"","lastName":"He","suffix":""}],"badges":[],"createdAt":"2024-06-16 08:09:56","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4588928/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4588928/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":60025883,"identity":"8cfbb4e2-59e4-4a78-877c-89c0a099ab33","added_by":"auto","created_at":"2024-07-10 17:19:17","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":153228,"visible":true,"origin":"","legend":"\u003cp\u003eFinite element simulation model.\u003c/p\u003e\n\u003cp\u003e(A) A3.3 type femoral intertrochanteric fracture model; (B) PFNA, PHLP and PFNA+PHLP internal fixation models; (C) Orthostatic cross-sectional view of PFNA internal fixation model; (D-E) PFNA and PFNA+ PHLP internal fixation assembly models.\u003c/p\u003e","description":"","filename":"Fig1Finiteelementsimulationmodel.png","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/cf78d17a2cae888a9468b594.png"},{"id":60025086,"identity":"e860047f-5e8a-4330-b63f-e2a9288b4b26","added_by":"auto","created_at":"2024-07-10 17:03:17","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":223576,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of loading conditions.\u003c/p\u003e","description":"","filename":"Fig2Schematicofloadingconditions..png","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/2ebc0c4cdd47f79f58bed089.png"},{"id":60025089,"identity":"7c0d7067-b008-48c0-9c82-1178d25c6716","added_by":"auto","created_at":"2024-07-10 17:03:17","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":731993,"visible":true,"origin":"","legend":"\u003cp\u003eThe Von Mises stress distribution nephogram for two internal fixation models at different loads.\u003c/p\u003e\n\u003cp\u003e(A) The Von Mises stress distribution nephogram of PFNA under static state; (B) The Von Mises stress distribution nephogram of PFNA under dynamic state; (C) The Von Mises stress distribution nephogram of PFNA+PHLP under static state; (D) The Von Mises stress distribution nephogram of PFNA+PHLP under dynamic state.\u003c/p\u003e","description":"","filename":"Fig3..png","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/341eb5a2a0a43d34a04c69df.png"},{"id":60025088,"identity":"1de2065f-c3e2-46cd-ab4b-950b3712930f","added_by":"auto","created_at":"2024-07-10 17:03:17","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":574002,"visible":true,"origin":"","legend":"\u003cp\u003eThe displacement distribution nephogram for two internal fixation models at different loads.\u003c/p\u003e\n\u003cp\u003e(A) Displacement distribution nephogram of PFNA under static state; (B) Displacement distribution nephogram of PFNA under dynamic state; (C) Displacement distribution nephogram of PFNA+PHLP under static state; (D) Displacement distribution nephogram of PFNA+PHLP under dynamic state.\u003c/p\u003e","description":"","filename":"Fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/d9d97d540188dd4099df7c2b.png"},{"id":60025682,"identity":"97bae173-4f64-481a-9b8d-b1b7ec033a19","added_by":"auto","created_at":"2024-07-10 17:11:17","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":124979,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the Von Mises stress in each part of two internal fixation models at different loads.\u003c/p\u003e\n\u003cp\u003e(A) The Von Mises stress in each part of PFNA internal fixation and PFNA + PHLP internal fixation under static state; (B) The Von Mises stress in each part of PFNA internal fixation and PFNA + PHLP internal fixation under dynamic state.\u003c/p\u003e","description":"","filename":"Fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/dcb9defbc17a81c7889357c5.png"},{"id":60025090,"identity":"b12f8787-ccfd-4c6a-a71c-95e6f9f1f05f","added_by":"auto","created_at":"2024-07-10 17:03:17","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":379976,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the displacement in each part of two internal fixation models at different loads.\u003c/p\u003e\n\u003cp\u003e(A) The displacement in each part of PFNA internal fixation and PFNA + PHLP internal fixation under static state; (B) The displacement in each part of PFNA internal fixation and PFNA + PHLP internal fixation under dynamic state.\u003c/p\u003e","description":"","filename":"Fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/7b8528662126be786c1e2335.png"},{"id":82197081,"identity":"56b3ba59-500a-44fe-b285-7b64c9004ca5","added_by":"auto","created_at":"2025-05-07 15:17:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2870322,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4588928/v1/8ea25ba1-b2d6-4daf-a6b8-1df9101fdf51.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Finite Element Analysis of PFNA and PFNA Combined with Locking Plate in Treatment of Femoral Intertrochanteric Fracture with Lateral Wall Fracture","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFemoral intertrochanteric fracture is a common type of hip fracture in the elderly. Although with a high fracture healing rate, the functional effect after the operation is often disappointing. Many patients cannot recover their activity level before the fracture, which is related to their physical condition, fracture type and internal fixation method .\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e As the proximal continuation of the femoral diaphysis, the lateral wall is anatomically defined as the horizontal area of the lateral cortex of the proximal femur between the vast lateralis ridge below the apex of the greater trochanter and the plane of the midpoint of the lesser trochanter.\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e A complete lateral wall provides the necessary support for the proximal bone fragments and the internal fixation spiral blade, which facilitates bone stabilization and reduces internal fixation stress and internal fixation failure rates.\u003csup\u003e[\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e The lateral wall is also the attachment point of the gluteus medius and gluteus minimus. The hip joint's soft tissue balance and stability will be significantly affected if the lateral wall is ruptured with reduction failure. Therefore, more scholars tend to reconstruct the lateral wall.\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eFemoral intertrochanteric fracture with lateral wall fracture is an unstable fracture. Applying PFNA fixation alone on patients is prone to complications such as coxa vara, internal fixation loosening and cutting out, resulting in internal fixation failure.\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e Clinically, some scholars attempted to achieve early stability by reconstructing the lateral femoral wall with locking plate, improving the mechanical conduction at proximal femoral and increasing the balance and stability of the soft tissues of hip joint. Through the comparison between the effects of locking plate reconstruction of the lateral wall and PFNA internal fixation, the former method proves to have obvious advantages in the aspects of fracture healing time, weight-bearing exercise time and improvement of hip joint function.\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e However, there are few reports on biomechanical research of the two internal fixation methods, which leads to the lack of basic data support. In this study, it was further confirmed that PFNA\u0026thinsp;+\u0026thinsp;PHLP had higher fixation strength and more reasonable stress distribution than PFNA internal fixation by analyzing the stress distribution and displacement distribution of internal fixation models under static and dynamic status of two internal fixation models of femoral intertrochanteric fracture with lateral wall fracture constructed by finite element, which provided theoretical support for clinical treatment.\u003c/p\u003e"},{"header":"Material and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n\u003ch2\u003eFemoral CT data\u003c/h2\u003e\n\u003cp\u003eThe target was a 57-year-old female volunteer, weight being 60kg, having no history of medical and surgical diseases, no limbs disability and trauma history. A 64-slice spiral CT was used to scan the bone tissue windows of bilateral upper femur, the scanning layer being 1mm in thickness, interval of 1 mm, ranging from 10cm above the vertex of greater trochanter to the plane of knee joint. The scanning data were saved in DICOM format and the data of the right femur were used as the specimen.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n\u003ch2\u003eExperimental software\u003c/h2\u003e\n\u003cp\u003eMimics Research 21.0, Geomagic Wrap, HyperMesh 2019, Creo 6.0, Abaqus 2020 were applied for data analysis and image processing.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n\u003ch2\u003eConstruction of A3.3 type Femoral Intertrochanteric Fracture Model\u003c/h2\u003e\n\u003cp\u003eImport the CT image data of the volunteer into Mimics Research 21.0, select the default threshold set \u0026ldquo;Bone (CT)\u0026rdquo; to identify the femur and then make the three-dimensional reconstruction of the right femur by Edit Masks, Smart Fill, Calculate Part, and Smooth. Following that, import the three-dimensional reconstruction into Geomagic Wrap in STL format, construct the A3.3 type femoral intertrochanteric fracture model by remeshing, deleting, and filling holes, and form the three parts of femoral head and neck bone, lesser trochanter bone, and femoral shaft bone (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eA). In the end, optimize the model by using the fitting surface and other operations, and save it in the format of STEP.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003eBuilding of PFNA Internal Fixation Model and PFNA\u0026thinsp;+\u0026thinsp;PHLP Internal Fixation Model\u003c/h2\u003e\n\u003cp\u003e3D modeling and assembly were carried out in Creo 6.0 to obtain PFNA, PHLP and PFNA\u0026thinsp;+\u0026thinsp;PHLP models (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eB). Orthotropic cross-sectional views of the PFNA internal fixation were obtained by defining the cross-section (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eC). The specifics of the internal fixation are shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Accemble the A3.3 type femoral intertrochanteric fracture model, the PFNA model, and the PFNA\u0026thinsp;+\u0026thinsp;PHLP model under the surgical standards in Abaqus 2020, ensuring that the positive position of spiral blade being in the 1/3 middle and lower position of the femoral neck, the lateral position of spiral blade being in the center of the femoral neck, with the tip-apex distance less than 20 mm, the locking plate located in the lateral side of the femur. In order to facilitate finite element modeling assembly, we opened a hole in the middle part of the plate through the steps of cutting geometry, geometric editing and the like and then conduct model combination. Simulate a self-locking nail for locking the plate by using commands such as coupling, binding and the like to carry out unicortical fixation on femur with three screws on the top and bottom. Import the model into HyperMesh 2019 in STEP format for meshing, using C3D10M as the element type, with the size of 2 mm, and its grid convergence was verified. Export the model in INP format to obtain the PFNA internal fixation assembly model (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eD) and PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation assembly model (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eE). The friction coefficient between bone was 0.46,the friction coefficient between bone and internal fixation was 0.3, and the friction coefficient between the spiral blade and the main nail was 0.23 \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eDetails of internal fixation.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eMaterials\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eModels and specifications\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eManufacturers\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePFNA\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e170 mm in the length of the main nail; 10 mm in the diameter of the spiral blade, 100 mm in length; 130⁰ in the collo-diaphyseal angle of the femur, and 5⁰ in the femoral valgus resection angle.\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSuzhou Xinrong Best Medical Instrument Co., Ltd.\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePHLP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eThree-hole plate with a length of 95 mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eIdeal (Suzhou) Medical Instrument Co., Ltd.\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n\u003ch2\u003eDefine Material Properties and Boundary Conditions\u003c/h2\u003e\n\u003cp\u003eImport the file of femoral mesh model of A3.3 type femoral intertrochanteric fracture into Mimics Research 21.0 in INP format, and divide the model into 10 materials according to the gray value. According to the empirical formula provided by Mimics: Density\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;13.4\u0026thinsp;+\u0026thinsp;1017 * Gray value, Young's modulus\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;388.8\u0026thinsp;+\u0026thinsp;5925 * Density. Poisson's ratio was 0.3, complete the assignment of femoral material propertie. Then import the file into Abaqus 2020 software in INP format. The material parameters of the internal fixation model were set as follows: Young's modulus was 110 GPa, with a Poisson's ratio of 0.3.\u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e The boundary conditions were all set as follows: the distal femur was completely fixed,the reference point was selected on the sphericity of the femoral head and defined as RP-1, and this point was coupled with some nodes of the sphericity of the femoral head. According to the body weight of volunteers, the z-direction load of 100% body weight(600 N) and 285% body weight (1710 N) were applied to the reference point (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e) to simulate the static load on the femur and the maximum dynamic load when walking at a speed of 4km/h.\u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n\u003ch2\u003eSubmit Calculation and Result Analysis\u003c/h2\u003e\n\u003cp\u003eAfter completing the above processing, select the Abaqus/Standard solver,set the running kernel and the memory, and submit the solution calculation. Mainly calculate the Von Mises stress and displacement distribution of two internal fixation models. Flollowing that, view and analyze the calculation results in Abaqus 2020 software.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eAccording to the analysis of the Von Mises stress nephogram (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e) and displacement nephogram (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e) of the two internal fixation models, the maximum Von Mises stress of PFNA internal fixation model and PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation model was 264.4Mpa and 152.1Mpa under static state, respectively, and the latter was reduced by about 40%. The maximum Von Mises stress of the former was located at the contact position of the spiral blade and the main nail, while that of the latter was near the junction of the plate and the spiral blade tail end. The stress distribution in the femoral was more uniform with PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation than with PFNA internal fixation.The maximum displacement of the two models were located at the top of the sphericity of the femoral head, with the value of 1.548mm of the former and 1.395mm of the latter. Under dynamic state, the maximum Von Mises stress of PFNA internal fixation model and PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation model was 774.9Mpa and 446.5Mpa, respectively, with the latter decreased by about 40%. The locations of the maximum Von Mises stress and displacement were consistent with those under static load. The maximum displacement was 5.688mm in the former and 5.115mm in the latter. The above data are summarized in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. Compared with PFNA fixation, PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation reduced the stress at the fracture end (including femoral head end, corpora femoris end and lesser trochanter end) and the main nail, especially at the main nail. The main nail\u0026rsquo;s Von Mises stress of PFNA fixation and PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation was 15.09Mpa and 9.03Mpa respectively in static state, and 45.35Mpa and 26.98Mpa respectively in dynamic state, which were reduced by about 40%. Little change was seen on the Von Mises stress of the femoral head, femoral neck, medial wall and spiral blade of PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). Compared with PFNA fixation, the overall displacement of femoral head, femoral neck, lateral wall and spiral blade of PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation were reduced in both static and dynamic state, but didn\u0026rsquo;t vary too much (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eThe Von Mises stress and displacement of the two internal fixation methods under dynamic and static state.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eInternal fixation methods\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eThe Von Mises stress under static state(Mpa)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eThe Von Mises stress under dynamic state(Mpa)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eThe displacement under static state(mm)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eThe displacement under dynamic state(mm)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePFNA\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e264.4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e774.9\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.548\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e5.688\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePFNA\u0026thinsp;+\u0026thinsp;PHLP\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e152.1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e446.5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.395\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e5.115\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eVon r\u0026uuml;den et al. considered the joint of the main nail and the spiral blade to be the main stress concentration area and the weak point of the head and neck type intramedullary nail.\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e In this study, it was found that the maximum Von Mises stress of PFNA fixation occurs at the contact position of spiral blade and main nail, while that of PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation was near the junction of the plate and the spiral blade tail end, and that of PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation decreased by about 40% under static and dynamic state. The change of the position of the maximum Von Mises stress and the reduction of the stress value avoided the internal fixation failure caused by the stress concentration. Regarding the femoral intertrochanteric fracture with lateral wall fracture, Wang Renkai et al. proposed the five-point stability theory, which believed that the head end of the spiral blade, the main nail at the entrance of the greater trochanter, the proximal end of the lateral wall fracture, the distal end of the lateral wall fracture, and the distal locking nail formed a stable frame structure. And the lateral plate connecting the proximal end and the distal end of the femur enhanced the stability of the fracture end.\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e Compared with PFNA fixation, the Von Mises stress of main nail of PFNA\u0026thinsp;+\u0026thinsp;PHLP fixation was reduced by about 40% under both dynamic and static load, and the Von Mises stress of the lateral wall was increased in the same condition, which was realated to the use of the plate and nail to fix the lateral wall. The Von Mises stress of the plate in the static state was 11.77Mpa, and 34.76Mpa in the dynamic state, taking away more stress off the main nail, thus making the stress distribution of the whole internal fixation system more reasonable. The decline of the stress at the fractured end further proves that the reconstruction of the lateral wall by PHLP could enhance the stability of the internal fixation, which was consistent with the five-point stability theory proposed by Wang Renkai et al, while the stress the femoral head, femoral neck, medial wall and spiral blade took did not change much. According to the displacement nephogram, the maximum displacements of the two internal fixations were located at the top of the sphericity of femoral head, and there was no significant difference between static and dynamic states. When using PHLP to fix the lateral wall, the displacement of femoral head, femoral neck, lateral wall and spiral blade were also reduced, but not greatly. It indicated that there was little effect on the displacement when reconstructing the lateral wall by PHLP, and it obviously improved the stress distribution and fixation strength.\u003c/p\u003e \u003cp\u003ePFNA intramedullary fixation has always been considered as the high standard for internal fixation of femoral intertrochanteric fracture surgery due to its unique biomechanical and minimally invasive advantages, and the main nail can serve as the metal lateral wall, which can reduce the migration of bone mass to a certain extent.\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e However, internal fixation failure still exists when using PFNA method, especially in unstable fracture types with lateral wall fracture.\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e For unstable femoral intertrochanteric fractures with rupture lateral wall, especially type A3.3, scholars advocate reconstruction of the lateral wall in Stage I, and the use of nails, Kirschner wires, tension band, and plate to reconstruct the lateral wall according to different types of lateral wall fracture. It has a definite effect on clinical treatments, but lacks data supporting of basic theoretical research.\u003csup\u003e[\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e Internal fixation with steel plate was preferred for severe damage of lateral wall, considering the similarity between the structures of the proximal femur and the proximal humerus, we did not routinely select a narrow reconstruction locking plate to be placed anterolateral to the proximal femur, but creatively used PHLP to fix the lateral wall because of the larger width of PHLP, which could fix the lateral wall in a wider range. We also collected some clinical cases, found that PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation took a little longer operation time and had a little more bleeding than PFNA internal fixation, while the incidence of complications such as varus of the hip and the time of rehabilitation and exercise in the ground had obvious advantages. It could better improve the function of hip joint and enhance the surgical effect. However, the data sample size is not big enough, and more clinical cases will continue to be collected for retrospective study. In this paper, the common AO 31-A3.3 type femoral intertrochanteric fracture in clinic was taken as the research object, and the Von Mises stress distribution and displacement distribution of PFNA internal fixation and PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation under dynamic and static load were compared by finite element analysis for the first time, providing further theoretical data support for clinical treatment.\u003c/p\u003e \u003cp\u003eIn summary, we conclude that PFNA\u0026thinsp;+\u0026thinsp;PHLP internal fixation in treatment of femoral intertrochanteric fracture with lateral wall fracture has higher fixation strength and more reasonable stress distribution than PFNA internal fixation, which can allow patients to recover functional exercises and walking ability earlier after surgery, reduce complications and improve their quality of life. Of course, there are still some shortcomings in this experiment. The maximum load of the human walking was simulated by applying a constant load, but in fact, the human walking gait is a very complex process, which presents the gait cycle load. At the same time, the hip joint reaction force and the surrounding muscle force should be considered. The bone mineral density and elastic modulus of the femur in this experiment were deduced according to the empirical formula provided by Mimics, which might be different from the actual situation. Only a typical fracture type was studied. Subsequently, the finite element analysis of the hip joint under walking condition will be further optimized, and the comparison of fracture models with different bone mineral density and elastic modulus will be perfected to better guide the surgical internal fixation plan for the clinical treatment of femoral intertrochanteric fracture with lateral wall fracture.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003ePFNA \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;Proximal Femoral Nail Antirotation\u003c/p\u003e\n\u003cp\u003ePHLP \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;Proximal Humerus Locking Plate\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLZ and SJH conceived and designed the study. YDB and RX built the finite element model. LZ and RX analyzed the data. SJH and LWL revised the article. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by grants from the Clinical Key Diseases\u0026rsquo; Diagnosis and Treatment of Suzhou (LCZX202135) and the Research Program of Suzhou Science and Technology (SKY2023117).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAlmost all data generated or analysed during this study are included in this published article. The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was approved by the ethics committee of Suzhou Hospital, Affiliated Hospital of Medical School, Nanjing University. Signing the informed consent was waived by the ethics committee of Suzhou Hospital, Affiliated Hospital of Medical School, Nanjing University.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLisk R, Yeong K. 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The effect on outcomes of the application of circumferential cerclage cable following intramedullary nailing in reverse intertrochanteric femoral fractures. Eur J Orthop Surg Traumatol. 2019;29(4):835\u0026ndash;42.\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":"femoral intertrochanteric fracture, femoral lateral wall, intramedullary nail, plate, finite element analysis","lastPublishedDoi":"10.21203/rs.3.rs-4588928/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4588928/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eThe biomechanical characteristics of Proximal Femoral Nail Antirotation (PFNA) and PFNA combined with Proximal Humerus Locking Plate (PHLP) in treatment of femoral intertrochanteric fracture with lateral wall fracture were compared by finite element analysis, and the biomechanical strength, stress and displacement distribution of the two internal fixation methods were compared.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eA healthy middle-aged female patient was selected. According to the femur CT scan data, the three-dimensional finite element models of the femur, PFNA, and PHLP were established .The simulated AO classification was 31-A3.3 femoral intertrochanteric fracture, and the two internal fixation assembly models of PFNA and PNFA+PHLP were established. The von mises stress distribution and displacement distribution nephograms of the two internal fixation models were observed when the same load was applied on the two models under the dynamic and static status.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResult: \u003c/strong\u003eCompared with PFNA fixation, PFNA+PHLP fixation reduced the maximum von mises stress by about 40%, while the maximum displacement changed little. The stress at the fracture end and the main nail position decreased, with a noticeablereduction of about 40% at the main nail. The Von Mises stress of the femoral head, femoral neck, medial, wall and spiral blade changed little. The total displacement of the femoral head, femoral neck, lateral wall, and spiral blade of PFNA+PHLP fixation decreased insignificant.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003ePFNA + PHLP internal fixation in the treatment of femoral intertrochanteric fracture with lateral wall fracture has higher fixation strength and more reasonable stress distribution than PFNA internal fixation.\u003c/p\u003e","manuscriptTitle":"Finite Element Analysis of PFNA and PFNA Combined with Locking Plate in Treatment of Femoral Intertrochanteric Fracture with Lateral Wall Fracture","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-10 17:03:12","doi":"10.21203/rs.3.rs-4588928/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":"98f39266-99a1-4e37-8ecb-293e66adcefa","owner":[],"postedDate":"July 10th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-05-07T15:08:47+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-10 17:03:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4588928","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4588928","identity":"rs-4588928","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}