Analysing plate fixation of a comminuted fracture of the proximal ulna in relation to the elbow joint: A finite element study

Analysing plate fixation of a comminuted fracture of the proximal ulna in relation to the elbow joint: A finite element study | 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 Analysing plate fixation of a comminuted fracture of the proximal ulna in relation to the elbow joint: A finite element study Jindřich Šafran, Tomáš Pavlacký, Petr Marcián, Radim Herůfek, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6596375/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Jul, 2025 Read the published version in Journal of Orthopaedic Surgery and Research → Version 1 posted 18 You are reading this latest preprint version Abstract This study investigated the biomechanical behavior of four different screw configurations used to fix comminuted proximal ulna fractures with a locking compression plate (LCP), via a detailed finite element model based on realistic anatomical geometry. The model incorporated both cortical and cancellous bone, soft tissue constraints, and loading conditions to represent the physiological self-weight of the forearm. The stress distribution on the plate, strain intensity within the bone tissue, and interfragmentary motion (IFM) between fracture fragments were evaluated for each configuration. The results indicate that all the tested configurations provide adequate stability under normal loading conditions, with no risk of material failure. However, excessive stress concentrations were observed in specific screw regions depending on the configuration, particularly when screws anchoring the olecranon were omitted. Strain analysis revealed moderate physiological bone loading across variants, whereas IFM assessment highlighted the importance of securing the coronoid and apical fragments to prevent compromised healing. These findings suggest that reduced use of osteosynthetic material may be sufficient for fracture stabilisation, potentially minimising implant-related complications. This modelling approach offers a valuable tool for preclinical assessment of osteosynthesis strategies and supports future comparative research on fixation methods with varying biomechanical properties. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Introduction With an incidence of 12–15 cases per 10,000 inhabitants[ 1 ], [ 2 ] proximal ulna fractures account for 8–10% of skeletal injuries of the upper limb. In 80% of cases, these fractures are olecranon fractures that, in a border context, belong to the category of osteoporotic fractures, and a further increase in their incidence can certainly be expected in the coming decades. All of these fractures are intra-articular in nature, so the ultimate goal is to restore joint function. Anatomic repositioning, retention, and early mobilisation are recommended as the current standard of care for virtually all proximal ulna fractures and yield the best results[ 3 ], [ 4 ]. Currently, the most widely used technique for open repositioning and internal fixation is the use of tension band wires (K-wires) and cerclage. However, a significant limitation of this technique is that it is found in comminuted fractures, where cerclage alone may not allow adequate fragment stabilisation [ 3 ]. On the other hand, osteosynthesis in this location requires the use of the smallest necessary osteosynthetic material because of the anatomical conditions and minimal amount of subcutaneous tissue. One way to perform a sufficient fixation assessment is to analyse the strain-stress states. The initial stability and modulation of mechanical forces at the fracture site can significantly influence the healing rate. These factors determine whether the fracture will heal through a direct or indirect pathway and ultimately via intramembranous or endochondral ossification [ 5 ]. Primary healing can be obtained by means of absolute stability and results in direct bone formation and osteonal bridging of the fracture gap. Bridging with a locking compression plate (LCP) is one of the methods of relative stability. It causes indirect healing and relies on some instability at the fracture site, which allows interfragmentary motion (IFM). This promotes callus formation and bridging of the bone [ 6 ]. Controlled early axial IFM is known to increase callus growth, subsequently affecting the callus in terms of both size and composition [ 6 ]. The aim of this study was to investigate and analyse, via in silico experimental modelling, the mechanical behavior of a comminuted proximal ulnar fracture fixed with a screw-locking LCP. The analysis is aimed at assessing the mechanical interaction between the fragment surfaces on the basis of the loading of the fixed fracture with the LCP. Furthermore, this study aimed to compare strain intensity and interfragmentary motion (IFM) in fragments required for bone healing [ 7 ], as well as stress on the LCP, across four fixation variants. The analysis of stress and strain was performed via the finite element method in software ANSYS® Academic Research Mechanical, Release 22.2 (Swanson Analysis, Inc., Houston, PA, USA). Materials and Methods The computational model of the elbow joint with fracture was created on the basis of typical fracture planes of the fracture[ 8 ] (fracture type 2U1C3 by AO classification of proximal ulna fracture), selected with respect to clinical practice, to be as close as possible to real anatomical and pathological conditions. The position of the elbow joint was determined on the basis of the typical neutral position of the affected area after the surgical procedure [ 9 ]. The screw choices and number of screws were selected on the basis of clinical experience with respect to the recommendation of the AO foundation [ 10 ]. Model of Geometry For the purpose of this study two sets of images were used, which were obtained from Trauma Hospital Brno, Czech Republic (see Fig. 1 ). The first dataset (0.3x0.3x0.4 mm in size) was used to create credible elbow fracture planes. The second dataset of healthy elbow joint ( 0.23x0.23x1 mm in size) was used to segment the model geometry. In both cases, the images depicted the entire elbow joint consisting of the ulna, radius and humerus. The CT datasets were converted into a standard tessellation language (STL) format file to acquire a geometry model of the elbow. All necessary image processing procedures were performed via MATLAB R2022b (Math Works, Natick, MA, USA) [ 11 ]. CT images of the fracture were used to segment the shape and position of the fracture planes to create individual fragments of the comminuted fracture. Cartilages were created by extending the surfaces into space by 1 mm (due to uneven thickness[ 12 ], this value was consulted with the anatomist) and then creating volume solids in Catia V5 (Dassault Systèmes, France). Owing to the complexity of the LCP geometry, the LCP was scanned via a 3D scanner (Shining3D EinScan SE, SHINING 3D Technology GmbH, Stuttgart, Germany) and converted to a model geometry. The locking screws and cortical screw were measured and modelled in Catia V5 (Dassault Systèmes, France). The plate was attached to the fracture fragments via 9 screws (8 with a locking mechanism and 1 cortical screw) with different dimensions (see Table 1 ). The screws and plate were placed in position according to the fracture planes (see Fig. 3 ). For the purpose of assessing the analysed parameters in various clinical situations, 4 variants of fracture fixation were created, which differ in the number of screws used (see Fig. 4 ). Table 1 Dimensions of using screws in the model and variant missing. Screws Diameter [mm] Length [mm] Variant missing Locking screw 1 3.45 38 No missing Locking screw 2 3. 45 6 Variant 3 Locking screw 3 3. 45 20 Variant 3 Locking screw 4 3. 45 26 No missing Locking screw 5 3. 45 38 Variant 4 Locking screw 6 3. 45 20 No missing Locking screw 7 3. 45 20 Variant 2, Variant 4 Locking screw 8 3. 45 18 No missing Cortical screw (CS) 3.4 36 No missing Material model Lineically elastic, isotropic and homogeneous material models were used in this study on the basis of the literature (see Table 2 ). According to the manufacturer (Zimmer® Universal Locking System [ 13 ]), a plate and screws with locking heads were made from stainless steel alloy (22-13-5), and a cortical screw without a locking mechanism was made from stainless steel (316L) from the manufacturer MEDIN, a.s. (Information from MEDIN Traumatology Catalogue [ 14 ]). Table 2 Material properties. Material Young’s Modulus [MPa] Poisson‘s ration [-] References Cortical bone 17 560 0.325 [ 15 ], [ 16 ] Cancellous bone 2100 0.3 [ 15 ], [ 17 ], [ 18 ] Cartilage 50 0.45 [ 19 ] Stainless steel (316L) 193000 0.25 [ 20 ], [ 21 ] Stainless steel (22-13-5) 200000 0.28 [ 22 ], [ 23 ] Loading and Constrains For these variations, a loading scenario was modelled with the self-weight of the forearm and hand of the upper limb. The forearm represents 2.5%[ 24 ], and the hand represents 0.73% [ 24 ] of the total human weight. The average weight of a person 83.6 kg, the mass was determined to be 2.7 kg [ 25 ]. The position of the mass point, which represents the mass of the forearm, hand and plate with screws, was determined to be 159.8 mm from the edge of the olecranon of the ulna (see Fig. 5 ). Fixed support was avoided at the flat end of the humerus, and the gravitational acceleration of the Earth was determined for the whole model (see Fig. 5 ). The FE mesh of all the variants consisted of a ten-node high-order element (Ansys elements SOLID187), and Ansys elements LINK180 were used to model the muscles and ligaments in isometric contraction[ 26 ]. The locations of the muscles, ligaments and tendons were determined by consultation with an anatomist. The positions of the original tendons or those attached to the geometry model were solved by remote points. All the parts were connected by contact elements (Ansys elements TARGE170 and CONTA174), assuming a conservative variant. All friction surfaces were assumed to be frictionless, except for the interactions between the bone tissue parts (cartilage-cortical, cortical-cancellous), which were firmly connected. In this way, the clinically worst-case scenario was modelled. The cylindrical heads of the LCP-type screws were firmly connected to the plate as a result of the locking mechanism. The total number of elements ranged from approximately 1 500 000 to 1 418 000. Furthermore, a mesh sensitivity analysis was performed to determine the influence of the element size on the accuracy and convergence of the investigated parameters. For a more detailed analysis, sub-models were created in the areas with the highest achieved von Mises stress (see Fig. 7 ). These sub-models had a total number of elements ranging from 1 130 000 to 1 350 000. (element sizes: rounding of holes – 0.02 mm, faces of holes – 0.1 mm, faces of plate around holes – 0.05 mm). The solved sub-models were analysed for parts of the LCP, bone tissue and screw geometry model for a specific region. Bone tissue was included in the sub-models because of the contact of bone tissue with the LCP. Evaluation Using equivalent von Mises stresses, the critical spots on the plate were assessed, and the strain values on the surface of the individual fragments were identified. Strain intensity and Frost’s mechanostat hypothesis [ 27 ] were used to assess and analyse the mechanical interaction of bone fragments. On the basis of the Frost mechanostat hypothesis, the evaluation was performed on the basis of the strain intensity. The calculation of strain intensity is represented by the following equation: $$\:{ϵ}_{i}=MAX\:\left|\left({ϵ}_{1}-{ϵ}_{2}\right),\left({ϵ}_{2}-{ϵ}_{3}\right),{(ϵ}_{3}-{ϵ}_{1})\right|,$$ where \(\:{ϵ}_{i}\) is the strain intensity and where \(\:{ϵ}_{1}\) , \(\:{ϵ}_{2}\) and \(\:{ϵ}_{3}\) represent the principal strains. The strain intensity is expressed in the results in terms of \(\:\:ϵ\) , where \(\:0.001ϵ\) = 0.1% [ 28 ]. Finally, the IFM (interfragmentary motion) between the fragments was monitored, which according to previous studies [ 29 ], has a positive effect on the healing of bone tissue under certain circumstances. The IFM-Calculator software [ 30 ] in the Python development environment was used to determine the IFM. Results Figure 9 shows the distributions of the equivalent von Mises stresses on the plate for all the solved variants. For variants 1–3, the highest stress is in the area of locking screw 5 (see details in Fig. 9 ). The highest values of the equivalent stress range from 90 MPa to 120 MPa for variant 1. The lowest equivalent stress on the plate is in the case of variant 4, which lacks a locking screw (screw 5) and one screw in the diaphysis of the ulna (screw 7). The maximal equivalent stress is 98 MPa in the area of locking screw 1, which is in the olecranon of the ulna bone. The results from the sub-model for variants 1–3 in the locking screw 5 region are shown in Fig. 10 , and the highest equivalent stress ranges from 200 MPa to 350 MPa for Variant 3. For Variant 4, the highest equivalent stress value is in the locking screw 2 region. Figure 11 shows the equivalent strain intensity on the inner surface of the bone fragments. Fragment C near locking screw 5 is the fragment with the highest strain values, as it is the most mechanically loaded. The bone tissues near the screws are slightly overloaded, and the strain is greater than \(\:0.003ϵ\) . The highest values of strain intensity in the bone tissues were observed in Variant 4. The relative displacements are evaluated via IFM and are presented in Figs. 12 – 14 for the analysed fragments. The highest values of relative displacement are obtained in the case of Fragment A (olecranon), which is 0.041 mm. The highest displacements were always obtained in the case of Variant 4, as well as in the case of strain intensity analysed in bone tissue, and the other variants of screw insertion were comparable. Discussion Olecranon fractures are among the most common upper limb injuries. By definition, they are predominantly intra-articular fractures that have been treated surgically for decades, with the primary goal of achieving optimal functional outcomes. Surgical management typically adheres to the fundamental principles established by expert organisations e.g. the AO Foundation [ 10 ], which relies heavily on empirical approaches—likely due to the absence of a universally applicable method. This has led to the development and adoption of various alternative osteosynthesis techniques in addition to two conventionally established methods. Nevertheless, the literature reports a high incidence of complications and secondary surgeries in this context [ 31 ], [ 32 ], [ 33 ]. Some of these complications are associated with inadequate fracture healing and are often influenced by inappropriate fixation related to the number, direction and length of locking screws used [ 34 ]. In silico experiments using a computational model that incorporates all relevant anatomical and biomechanical parameters may help predict and prevent such complications. In our model, a complex fracture with characteristic fracture lines was intentionally selected [ 34 ]. This study examined how the number of screws affects LCP loading, bone remodelling, and interfragmentary motion (IFM), with the aim of evaluating and comparing bone healing outcomes. Four screw configuration variants were developed, and comparative biomechanical analyses were performed. The equivalent von Mises stress on the LCP was assessed across all the screw configurations. Due to the nature of loading, only static stress was analysed in the neutral postoperative position of the ulna, with high-cycle fatigue being excluded [ 8 ]. The analysis was conducted with respect to the standard healing period of 3–6 months [ 35 ]. The Sub-models were used to focus on the regions with the highest stress concentrations. For Variants 1–3, the maximum stress occurred near locking screw 5. The stress values ranged from 200 MPa to 350 MPa, with the highest observed in Variant 3, where screws 2 and 3—anchoring the olecranon—were omitted. In Variant 4, the stress concentration shifted toward the olecranon due to the absence of screw 5, where local plasticisation exceeding 415 MPa was observed in the screw hole region [ 36 ]. The LCP maintains the relative position of the bone fragments [ 35 ], allowing slight interfragmentary movement, which generates varying loads on the bone tissue. The equivalent strain intensity results indicate moderate loading of the bone tissue, which is consistent with physiological strain and normal bone remodelling due to fragment interactions. Most strain values ranged from 0.0001 to 0.0015 mm/mm, suggesting a healthy remodelling response. None of the configurations exceeded an equivalent strain of 0.025 mm/mm, which is indicative of pathological bone overloading or potential fracture strain[ 37 ], [ 38 ]. Fixation stability was also evaluated through analysis of the IFM. In all the tested configurations, the IFM values suggested sufficient stability for successful fracture healing [ 39 ], [ 40 ]. Variants 1–3 presented comparable IFM values, whereas Variant 4 presented the highest IFM, particularly in the olecranon region (Fragment A), where motion exceeded 0.036 mm. For comparison, Kenwright and Goodship recommended an optimal IFM of 0.2–1.0 mm in the diaphyseal region to support secondary bone healing [ 41 ], [ 42 ], and Wolf et al. proposed a 0.4 mm threshold in diaphyseal osteotomies where callus formation is also desired [ 43 ]. However, few studies have evaluated IFM in periarticular regions where primary bone healing is preferred, as callus formation is typically absent. These studies generally agree that the IFM should not exceed 0.03 mm in such contexts [ 44 ]. Thus, the elevated IFM observed in Variant 4 may compromise primary healing. In contrast, the IFM values in the other configurations fall within acceptable limits, supporting primary bone healing. This finding indicates that the studied construct is not excessively rigid across configurations. Nonetheless, the IFM results highlight the importance of securely fixing the coronoid (Fragment B), as insufficient fixation in this area risks exceeding the critical IFM threshold of 0.02 mm [ 42 ], potentially leading to fragment displacement under load. Similarly, fixation of the apical fragment of the olecranon (Fragment A) is critical and typically ensured by standard plate designs. Conclusion This study evaluated four fixation variants for comminuted fractures of the proximal ulna, which differ in the number of screws used. The results of the stress and strain analysis revealed several important findings. The use of a 3.5 mm LCP and screws provides sufficient structural stability in this anatomical region. Given the recorded load levels, material failure under normal physiological conditions is unlikely. Therefore, the use of less bulky implants may be both adequate and desirable, as it could reduce patient discomfort related to implant prominence. The elevated bone loading around the screws further supports the established principle that screws should not engage directly with fracture lines. On the other hand, IFM analysis revealed that the presence of a coronoid fragment necessitates sufficient fixation with at least one screw to avoid exceeding the critical motion threshold, which could otherwise compromise articular healing or cause fragment detachment under early loading. Similar fixation requirements apply to the apical fragment of the olecranon, although these requirements are typically addressed by standard pre-contoured plate designs. The remaining IFM values observed across all the other configurations remained within the range favour able for primary bone healing, indicating that none of the studied constructs are excessively stiff. For future applications of this computational model, it would be valuable to compare various osteosynthesis techniques with differing biomechanical characteristics. Such comparative studies should be pursued in further research. Declarations Author Contribution J.Š. conceptualization, writing - original draft, investigation, visualization, methodology, writing - review and editing. T.P. conceptualization, writing - original draft, investigation, visualization, methodology, writing - review and editing. P.M. conceptualization, methodology, supervision, writing - review and editing, funding acquisition. R.H. investigation, visualization, methodology. R.V. conceptualization, methodology, supervision. Data Availability Data is provided within the manuscript or supplementary information files.DOI: 10.5281/zenodo.15155804 References Court-Brown CM, Caesar B. ‘Epidemiology of adult fractures: A review’, Injury , vol. 37, no. 8, pp. 691–697, Aug. 2006, 10.1016/j.injury.2006.04.130 Duckworth AD, Clement ND, Aitken SA, Court-Brown CM, McQueen MM. ‘The epidemiology of fractures of the proximal ulna’, Injury , vol. 43, no. 3, pp. 343–346, Mar. 2012, 10.1016/j.injury.2011.10.017 Wilkerson JA, Rosenwasser MP. Surgical Techniques of Olecranon Fractures. J Hand Surg Am. Aug. 2014;39(8):1606–14. 10.1016/j.jhsa.2014.05.014 . Tarallo L, Mugnai R, Adani R, Capra F, Zambianchi F, Catani F. ‘Simple and comminuted displaced olecranon fractures: a clinical comparison between tension band wiring and plate fixation techniques’, Arch Orthop Trauma Surg , vol. 134, no. 8, pp. 1107–1114, Aug. 2014, 10.1007/s00402-014-2021-9 Augat P, Simon U, Liedert A, Claes L. Mechanics and mechano-biology of fracture healing in normal and osteoporotic bone. Osteoporos Int. Mar. 2005;16:S36–43. 10.1007/s00198-004-1728-9 . Klein P et al. Jul., ‘The initial phase of fracture healing is specifically sensitive to mechanical conditions’, Journal of Orthopaedic Research , vol. 21, no. 4, pp. 662–669, 2003, 10.1016/S0736-0266(02)00259-0 Miramini S, Zhang L, Richardson M, Mendis P, Oloyede A, Ebeling P. The relationship between interfragmentary movement and cell differentiation in early fracture healing under locking plate fixation. Australas Phys Eng Sci Med. Mar. 2016;39(1):123–33. 10.1007/s13246-015-0407-9 . Lubberts B, Mellema JJ, Janssen SJ, Ring D. Fracture line distribution of olecranon fractures. Arch Orthop Trauma Surg. Jan. 2017;137(1):37–42. 10.1007/s00402-016-2593-7 . Morrey BF. Functional Evaluation of the Elbow. Morrey’s the Elbow and its Disorders. Elsevier; 2018. pp. 66–74. 10.1016/B978-0-323-34169-1.00005-X . Hodgson S, ‘AO Principles of Fracture Management’. Jul.,, The Annals of The Royal College of Surgeons of England , vol. 91, no. 5, pp. 448–449, 2009, 10.1308/rcsann.2009.91.5.448b Marcián P et al. Jan., ‘On the level of computational models in biomechanics depending on gained data from CT/MRI and micro-CT’, Mendel , pp. 455–462, 2011. Shepherd DET, Seedhom BB. Thickness of human articular cartilage in joints of the lower limb. Ann Rheum Dis. Jan. 1999;58(1):27–34. 10.1136/ard.58.1.27 . Zimmer, Biomet. ‘Zimmer® Universal Locking System’. a. s. MEDIN, ‘Catalogues – MEDIN, a.s.’. Rho JY, Hobatho MC, Ashman RB. Relations of mechanical properties to density and CT numbers in human bone. Med Eng Phys. 1995;17(5):347–55. https://doi.org/10.1016/1350-4533(95)97314-F . Cowin SC, Sadegh AM. Non-interacting modes for stress, strain and energy in anisotropic hard tissue. J Biomech. 1991;24(9):859–67. https://doi.org/10.1016/0021-9290(91)90311-A . Rho J-Y, Tsui TY, Pharr GM. ‘Elastic properties of human cortical and trabecular lamellar bone measured by nanoindentation’, Biomaterials , vol. 18, no. 20, pp. 1325–1330, 1997, https://doi.org/10.1016/S0142-9612(97)00073-2 Reilly DT, Burstein AH, Frankel VH. The elastic modulus for bone. J Biomech. 1974;7(3):271–5. https://doi.org/10.1016/0021-9290(74)90018-9 . Peña E, Calvo B, Martínez MA, Doblaré M. A three-dimensional finite element analysis of the combined behavior of ligaments and menisci in the healthy human knee joint. J Biomech. 2006;39(9):1686–701. https://doi.org/10.1016/j.jbiomech.2005.04.030 . Bevan MA et al. ‘Mechanical Properties and Behavior of Additive Manufactured Stainless Steel 316L’, 2017, pp. 577–583. 10.1007/978-3-319-51382-9_63 Kang L, Chen F, Bradford MA, Liu X. ‘Experimental study of mechanical properties of laser additively manufactured 316L stainless steels’, Structures , vol. 54, pp. 221–235, Aug. 2023, 10.1016/j.istruc.2023.05.053 Kusy RP, Dilley GJ. ‘Materials Science Elastic Modulus of a Triple-stranded Stainless Steel Arch Wire via Three- and Four-point Bending’, J Dent Res , vol. 63, no. 10, pp. 1232–1240, Oct. 1984, 10.1177/00220345840630101401 Odegard BC, West AJ. On the thermo-mechanical behavior and hydrogen compatibility of 22-13-5 stainles steel. Mater Sci Eng. Jun. 1975;19(2):261–9. 10.1016/0025-5416(75)90113-5 . Aydın, Tözeren. ‘Human Body Dynamics’, p., 2000, 10.1007/b97432 Walpole SC, Prieto-Merino D, Edwards P, Cleland J, Stevens G, Roberts I. The weight of nations: an estimation of adult human biomass. BMC Public Health. Dec. 2012;12(1):439. 10.1186/1471-2458-12-439 . Reed J, Bowen JD. Chapter 33 - Principles of Sports Rehabilitation. In: Seidenberg PH, Beutler AI, editors. The Sports Medicine Resource Manual. Philadelphia: W.B. Saunders; 2008. pp. 431–6. https://doi.org/10.1016/B978-141603197-0.10033-3 . Marcián P, Wolff J, Horáčková L, Kaiser J, Zikmund T, Borak L. Micro finite element analysis of dental implants under different loading conditions. Comput Biol Med. Mar. 2018;96. 10.1016/j.compbiomed.2018.03.012 . Frost H. ‘A 2003 update of bone physiology and Wolff’s Law for clinicians’, Angle Orthod , vol. 74, pp. 3–15, Mar. 2004, 10.1043/0003-3219(2004)0742.0.CO;2 Yamaji T, Ando K, Wolf S, Augat P, Claes L. The effect of micromovement on callus formation. J Orthop Sci. 2001;6:571–5. https://doi.org/10.1007/s007760100014 . Sun J, Wu L, Fang N, Liu L. IFM calculator: An algorithm for interfragmentary motion calculation in finite element analysis. Comput Methods Programs Biomed. 2024;244:107996. https://doi.org/10.1016/j.cmpb.2023.107996 . Bethell MA, et al. Complications Associated with Surgical Management of Olecranon Fractures. JBJS Rev. Mar. 2025;13(3). 10.2106/JBJS.RVW.24.00163 . Qi H, et al. Comparison of clinical outcomes of three internal fixation techniques in the treatment of olecranon fracture: a retrospective clinical study. BMC Musculoskelet Disord. Dec. 2022;23(1):521. 10.1186/s12891-022-05482-8 . Powell AJ, Farhan-Alanie OM, McGraw IWW. ‘Tension band wiring versus locking plate fixation for simple, two-part Mayo 2A olecranon fractures: a comparison of post-operative outcomes, complications, reoperations and economics’, Musculoskelet Surg , vol. 103, no. 2, pp. 155–160, Aug. 2019, 10.1007/s12306-018-0556-6 Norris BL, Lang G, Russell TA, Rothberg DL, Ricci WM, Borrelli J, editors. ‘Absolute Versus Relative Fracture Fixation: Impact on Fracture Healing’, J Orthop Trauma , vol. 32, no. 3, pp. S12–S16, Mar. 2018, 10.1097/BOT.0000000000001124 Siebenlist S, Torsiglieri T, Kraus T, Burghardt RD, Stöckle U, Lucke M. ‘Comminuted fractures of the proximal ulna—Preliminary results with an anatomically preshaped locking compression plate (LCP) system’, Injury , vol. 41, no. 12, pp. 1306–1311, Dec. 2010, 10.1016/j.injury.2010.08.008 Sumanariu CA, Amza CG, Baciu F, Vasile MI, Nicoara AI. ‘Comparative Analysis of Mechanical Properties: Conventional vs. Additive Manufacturing for Stainless Steel 316L’, Materials , vol. 17, no. 19, p. 4808, Sep. 2024, 10.3390/ma17194808 Tyrovola JB, Odont X. ‘The Mechanostat Theory of Frost and the OPG/RANKL/RANK System’, J Cell Biochem , vol. 116, no. 12, pp. 2724–2729, Dec. 2015, 10.1002/jcb.25265 Frost HM. ‘Wolff’s Law and bone’s structural adaptations to mechanical usage: an overview for clinicians’, Angle Orthod , vol. 64, no. 3, pp. 175–188, Jun. 1994, 10.1043/0003-3219(1994)0642.0.CO;2 Perren SM. ‘Evolution of the internal fixation of long bone fractures: The scientific basis of biological internal fixation: choosing a new balance between stability and biology’, J Bone Joint Surg , vol. 84, no. 8, pp. 1093–1110, Nov. 2002, 10.1302/0301-620X.84B8.13752 Claes L, Augat P, Suger G, Wilke H. ‘Influence of size and stability of the osteotomy gap on the success of fracture healing’, Journal of Orthopaedic Research , vol. 15, no. 4, pp. 577–584, Jul. 1997, 10.1002/jor.1100150414 Kenwright J, ‘EFFECT OF CONTROLLED AXIAL MICROMOVEMENT ON HEALING OF TIBIAL FRACTURES’. Nov.,, The Lancet , vol. 328, no. 8517, pp. 1185–1187, 1986, 10.1016/S0140-6736(86)92196-3 Rechter GR, Anthony RT, Rennard J, Kellam JF, Warner SJ. ‘The Impact of Early Axial Interfragmentary Motion on the Fracture Healing Environment: A Scoping Review’, Injury , vol. 55, no. 12, p. 111917, Dec. 2024, 10.1016/j.injury.2024.111917 Wolf S et al. Jun., ‘The effects of external mechanical stimulation on the healing of diaphyseal osteotomies fixed by flexible external fixation’, Clinical Biomechanics , vol. 13, no. 4–5, pp. 359–364, 1998, 10.1016/S0268-0033(98)00097-7 Carrera I, Gelber PE, Chary G, González-Ballester MA, Monllau JC, Noailly J. Fixation of a split fracture of the lateral tibial plateau with a locking screw plate instead of cannulated screws would allow early weight bearing: a computational exploration. Int Orthop. Oct. 2016;40(10):2163–9. 10.1007/s00264-015-3106-y . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Jul, 2025 Read the published version in Journal of Orthopaedic Surgery and Research → Version 1 posted Editorial decision: Revision requested 19 May, 2025 Reviews received at journal 19 May, 2025 Reviews received at journal 19 May, 2025 Reviews received at journal 16 May, 2025 Reviews received at journal 13 May, 2025 Reviewers agreed at journal 11 May, 2025 Reviewers agreed at journal 10 May, 2025 Reviewers agreed at journal 08 May, 2025 Reviewers agreed at journal 07 May, 2025 Reviewers agreed at journal 06 May, 2025 Reviewers agreed at journal 06 May, 2025 Reviewers agreed at journal 06 May, 2025 Reviewers agreed at journal 06 May, 2025 Reviewers agreed at journal 06 May, 2025 Reviewers invited by journal 06 May, 2025 Editor assigned by journal 05 May, 2025 Submission checks completed at journal 05 May, 2025 First submitted to journal 05 May, 2025 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-6596375","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":453821969,"identity":"26e70e3c-23ff-4326-abbf-1e872acefc4e","order_by":0,"name":"Jindřich Šafran","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Jindřich","middleName":"","lastName":"Šafran","suffix":""},{"id":453821970,"identity":"22b4456d-298a-4485-94da-bfd58b601e5e","order_by":1,"name":"Tomáš Pavlacký","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYNCCAgYGCQbmAwyMDUQo5gGTBiAtbAkka+ExIE6LPQPvwc88BnbykjNyvkkX7rjHwN9/gJAtfMnSPAbJhrMlcrdJzzxTzCBxgKAWHgPJGQbMCXIgLbxtCQwGhFwH1GL8c4ZBPVBLzjOIFmYCfgFqMZP4YHA4QVoihw2ihY2QlsN8aRYfDI4bzux5ZmzNeyaBR+IMAS3s7b2HbyRUVMtLHE9+eJt3R4IcwRBjYOaBMgQSoC4lDGBq+AkZPgpGwSgYBSMWAABkZDVaLEvYFgAAAABJRU5ErkJggg==","orcid":"","institution":"Masaryk University","correspondingAuthor":true,"prefix":"","firstName":"Tomáš","middleName":"","lastName":"Pavlacký","suffix":""},{"id":453821971,"identity":"51b507cd-35f1-44e1-a2b9-45a71593973c","order_by":2,"name":"Petr Marcián","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Petr","middleName":"","lastName":"Marcián","suffix":""},{"id":453821972,"identity":"696be674-84af-45ac-b893-c2d33bc2ecb9","order_by":3,"name":"Radim Herůfek","email":"","orcid":"","institution":"Trauma Hospital of Brno","correspondingAuthor":false,"prefix":"","firstName":"Radim","middleName":"","lastName":"Herůfek","suffix":""},{"id":453821973,"identity":"e337cb34-d3e5-4e57-9e9c-cf275396f1d3","order_by":4,"name":"Radek Veselý","email":"","orcid":"","institution":"Trauma Hospital of Brno","correspondingAuthor":false,"prefix":"","firstName":"Radek","middleName":"","lastName":"Veselý","suffix":""}],"badges":[],"createdAt":"2025-05-05 17:08:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6596375/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6596375/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13018-025-06031-4","type":"published","date":"2025-07-28T16:21:37+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":82331042,"identity":"950b2a8b-f524-46ed-900e-3ceec90b281b","added_by":"auto","created_at":"2025-05-09 07:17:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":4791681,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysing fracture of the ulna (left side – Model of the elbow joint with comminuted fracture; right side – CT image of the comminuted ulna).\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/3d86e4efefdfc54f5b8fe155.png"},{"id":82330467,"identity":"263e9852-936b-4e74-8801-db08e5f11398","added_by":"auto","created_at":"2025-05-09 07:09:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1787981,"visible":true,"origin":"","legend":"\u003cp\u003eComplete model of geometry with detail of cartilages models.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/73f14a9ea7c4f70432b37ce4.png"},{"id":82331036,"identity":"f48e244f-d151-4bea-ac5a-63111eb75c82","added_by":"auto","created_at":"2025-05-09 07:17:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1352748,"visible":true,"origin":"","legend":"\u003cp\u003eThe ulna with the position of the screws and visualisation of the fragment edges.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/6863a7fa8dcb4b7e04173031.png"},{"id":82331037,"identity":"20f32fb7-35a0-49ed-8ecf-64eb4e7e4d8b","added_by":"auto","created_at":"2025-05-09 07:17:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":897551,"visible":true,"origin":"","legend":"\u003cp\u003eAll variants of screws with plate (missing screws coloured red).\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/e5375f58f8dacd8c93687ec2.png"},{"id":82330487,"identity":"bbe2a123-9571-4c83-bc55-e4d4259f4938","added_by":"auto","created_at":"2025-05-09 07:09:33","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":454991,"visible":true,"origin":"","legend":"\u003cp\u003eVisualisation of loads and constraints for the computational model (red line – fixed, blue point – mass 2.7 kg)\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/5d832dc46636883aa3baf1a2.png"},{"id":82330469,"identity":"b06fa5a4-7179-4391-b2f7-92d2ffdc3eee","added_by":"auto","created_at":"2025-05-09 07:09:32","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":946814,"visible":true,"origin":"","legend":"\u003cp\u003eVisualisation positions of tendons for muscles and ligaments via the element LINK180 (blue lines – ligaments; red lines – muscles).\u003c/p\u003e","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/cacc2353b92aed8f6db3bc60.png"},{"id":82330498,"identity":"e564a83b-73c4-44a3-b188-293bf9224035","added_by":"auto","created_at":"2025-05-09 07:09:33","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":1516431,"visible":true,"origin":"","legend":"\u003cp\u003eProximal part of the ulna model with marked of friction and fixed areas.\u003c/p\u003e","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/be687c67ff60e291bb4f4e1a.png"},{"id":82330486,"identity":"260b45bb-492d-49f4-bffc-c5363849914e","added_by":"auto","created_at":"2025-05-09 07:09:33","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":2139223,"visible":true,"origin":"","legend":"\u003cp\u003eModel of geometry – used sub-models and visualisation of the sub-model mesh.\u003c/p\u003e","description":"","filename":"Figure8.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/e5be013feb23f69dfcead081.png"},{"id":82330525,"identity":"08b64cfc-8aa9-42dc-84f4-638ad057990e","added_by":"auto","created_at":"2025-05-09 07:09:34","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":3045373,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of von Mises stress for all the variants (focused areas have the highest equivalent stress distribution).\u003c/p\u003e","description":"","filename":"Figure9.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/a5b2a7a8e661e30e1c652713.png"},{"id":82330463,"identity":"f6911190-7c2e-48f1-b79c-e9850931ded4","added_by":"auto","created_at":"2025-05-09 07:09:31","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":2351638,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of von Mises stress for the results of sub modelling.\u003c/p\u003e","description":"","filename":"Figure10.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/c241f75b991a0808c7b7005f.png"},{"id":82330477,"identity":"9be9ad9e-98f0-42f9-ba2f-e2ade9cb06c2","added_by":"auto","created_at":"2025-05-09 07:09:32","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":5295824,"visible":true,"origin":"","legend":"\u003cp\u003eStrain intensity on each fragment on the fracture planes for each variant.\u003c/p\u003e","description":"","filename":"Figure11.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/c95da856ae617d80693cbb9e.png"},{"id":82332034,"identity":"350837ec-69e8-46b3-93f4-68b232fd05cb","added_by":"auto","created_at":"2025-05-09 07:25:33","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":3423287,"visible":true,"origin":"","legend":"\u003cp\u003eOlecranon fracture – IFM of Fragment A.\u003c/p\u003e","description":"","filename":"Figure12.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/f257b53cf3eae8aecf27a6ce.png"},{"id":82331048,"identity":"3d64a1e7-8446-441c-aefb-b7d0fc343663","added_by":"auto","created_at":"2025-05-09 07:17:33","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":3889536,"visible":true,"origin":"","legend":"\u003cp\u003eCoronoid fracture – IFM of Fragment B.\u003c/p\u003e","description":"","filename":"Figure13.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/8ebc399d4fbea9285334c011.png"},{"id":82330494,"identity":"83bd15e6-21e8-4247-b1ed-a5425eb92fa3","added_by":"auto","created_at":"2025-05-09 07:09:33","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":5553422,"visible":true,"origin":"","legend":"\u003cp\u003eIFM of Fragment C.\u003c/p\u003e","description":"","filename":"Figure14.png","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/797871455a1a264bbb3d85d7.png"},{"id":88268371,"identity":"166b7fb7-df3f-4a71-8f09-a074ab230221","added_by":"auto","created_at":"2025-08-04 16:51:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":34134553,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6596375/v1/bcf61df8-789e-4100-ac8a-f36bba3c2cda.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Analysing plate fixation of a comminuted fracture of the proximal ulna in relation to the elbow joint: A finite element study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eWith an incidence of 12\u0026ndash;15 cases per 10,000 inhabitants[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] proximal ulna fractures account for 8\u0026ndash;10% of skeletal injuries of the upper limb. In 80% of cases, these fractures are olecranon fractures that, in a border context, belong to the category of osteoporotic fractures, and a further increase in their incidence can certainly be expected in the coming decades. All of these fractures are intra-articular in nature, so the ultimate goal is to restore joint function. Anatomic repositioning, retention, and early mobilisation are recommended as the current standard of care for virtually all proximal ulna fractures and yield the best results[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Currently, the most widely used technique for open repositioning and internal fixation is the use of tension band wires (K-wires) and cerclage. However, a significant limitation of this technique is that it is found in comminuted fractures, where cerclage alone may not allow adequate fragment stabilisation [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. On the other hand, osteosynthesis in this location requires the use of the smallest necessary osteosynthetic material because of the anatomical conditions and minimal amount of subcutaneous tissue. One way to perform a sufficient fixation assessment is to analyse the strain-stress states.\u003c/p\u003e \u003cp\u003eThe initial stability and modulation of mechanical forces at the fracture site can significantly influence the healing rate. These factors determine whether the fracture will heal through a direct or indirect pathway and ultimately via intramembranous or endochondral ossification [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Primary healing can be obtained by means of absolute stability and results in direct bone formation and osteonal bridging of the fracture gap. Bridging with a locking compression plate (LCP) is one of the methods of relative stability. It causes indirect healing and relies on some instability at the fracture site, which allows interfragmentary motion (IFM). This promotes callus formation and bridging of the bone [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Controlled early axial IFM is known to increase callus growth, subsequently affecting the callus in terms of both size and composition [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe aim of this study was to investigate and analyse, via in silico experimental modelling, the mechanical behavior of a comminuted proximal ulnar fracture fixed with a screw-locking LCP. The analysis is aimed at assessing the mechanical interaction between the fragment surfaces on the basis of the loading of the fixed fracture with the LCP. Furthermore, this study aimed to compare strain intensity and interfragmentary motion (IFM) in fragments required for bone healing [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], as well as stress on the LCP, across four fixation variants. The analysis of stress and strain was performed via the finite element method in software ANSYS\u0026reg; Academic Research Mechanical, Release 22.2 (Swanson Analysis, Inc., Houston, PA, USA).\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eThe computational model of the elbow joint with fracture was created on the basis of typical fracture planes of the fracture[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (fracture type 2U1C3 by AO classification of proximal ulna fracture), selected with respect to clinical practice, to be as close as possible to real anatomical and pathological conditions. The position of the elbow joint was determined on the basis of the typical neutral position of the affected area after the surgical procedure [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The screw choices and number of screws were selected on the basis of clinical experience with respect to the recommendation of the AO foundation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eModel of Geometry\u003c/p\u003e \u003cp\u003eFor the purpose of this study two sets of images were used, which were obtained from Trauma Hospital Brno, Czech Republic (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The first dataset (0.3x0.3x0.4 mm in size) was used to create credible elbow fracture planes. The second dataset of healthy elbow joint ( 0.23x0.23x1 mm in size) was used to segment the model geometry. In both cases, the images depicted the entire elbow joint consisting of the ulna, radius and humerus. The CT datasets were converted into a standard tessellation language (STL) format file to acquire a geometry model of the elbow. All necessary image processing procedures were performed via MATLAB R2022b (Math Works, Natick, MA, USA) [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. CT images of the fracture were used to segment the shape and position of the fracture planes to create individual fragments of the comminuted fracture.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCartilages were created by extending the surfaces into space by 1 mm (due to uneven thickness[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], this value was consulted with the anatomist) and then creating volume solids in Catia V5 (Dassault Syst\u0026egrave;mes, France).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eOwing to the complexity of the LCP geometry, the LCP was scanned via a 3D scanner (Shining3D EinScan SE, SHINING 3D Technology GmbH, Stuttgart, Germany) and converted to a model geometry. The locking screws and cortical screw were measured and modelled in Catia V5 (Dassault Syst\u0026egrave;mes, France). The plate was attached to the fracture fragments via 9 screws (8 with a locking mechanism and 1 cortical screw) with different dimensions (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The screws and plate were placed in position according to the fracture planes (see Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). For the purpose of assessing the analysed parameters in various clinical situations, 4 variants of fracture fixation were created, which differ in the number of screws used (see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDimensions of using screws in the model and variant missing.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eScrews\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiameter [mm]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLength [mm]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVariant missing\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo missing\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVariant 3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVariant 3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo missing\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVariant 4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo missing\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVariant 2, Variant 4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocking screw 8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3. 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo missing\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCortical screw (CS)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo missing\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\u003eMaterial model\u003c/p\u003e \u003cp\u003eLineically elastic, isotropic and homogeneous material models were used in this study on the basis of the literature (see Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). According to the manufacturer (Zimmer\u0026reg; Universal Locking System [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]), a plate and screws with locking heads were made from stainless steel alloy (22-13-5), and a cortical screw without a locking mechanism was made from stainless steel (316L) from the manufacturer MEDIN, a.s. (Information from MEDIN Traumatology Catalogue [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMaterial properties.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaterial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYoung\u0026rsquo;s Modulus [MPa]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePoisson\u0026lsquo;s ration [-]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eReferences\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\u003e17 560\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.325\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\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\u003e2100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCartilage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStainless steel (316L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e193000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStainless steel (22-13-5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e200000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\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\u003eLoading and Constrains\u003c/p\u003e \u003cp\u003eFor these variations, a loading scenario was modelled with the self-weight of the forearm and hand of the upper limb. The forearm represents 2.5%[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], and the hand represents 0.73% [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] of the total human weight. The average weight of a person 83.6 kg, the mass was determined to be 2.7 kg [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The position of the mass point, which represents the mass of the forearm, hand and plate with screws, was determined to be 159.8 mm from the edge of the olecranon of the ulna (see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Fixed support was avoided at the flat end of the humerus, and the gravitational acceleration of the Earth was determined for the whole model (see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe FE mesh of all the variants consisted of a ten-node high-order element (Ansys elements SOLID187), and Ansys elements LINK180 were used to model the muscles and ligaments in isometric contraction[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The locations of the muscles, ligaments and tendons were determined by consultation with an anatomist. The positions of the original tendons or those attached to the geometry model were solved by remote points.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAll the parts were connected by contact elements (Ansys elements TARGE170 and CONTA174), assuming a conservative variant. All friction surfaces were assumed to be frictionless, except for the interactions between the bone tissue parts (cartilage-cortical, cortical-cancellous), which were firmly connected. In this way, the clinically worst-case scenario was modelled. The cylindrical heads of the LCP-type screws were firmly connected to the plate as a result of the locking mechanism.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe total number of elements ranged from approximately 1 500 000 to 1 418 000. Furthermore, a mesh sensitivity analysis was performed to determine the influence of the element size on the accuracy and convergence of the investigated parameters. For a more detailed analysis, sub-models were created in the areas with the highest achieved von Mises stress (see Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). These sub-models had a total number of elements ranging from 1 130 000 to 1 350 000. (element sizes: rounding of holes \u0026ndash; 0.02 mm, faces of holes \u0026ndash; 0.1 mm, faces of plate around holes \u0026ndash; 0.05 mm). The solved sub-models were analysed for parts of the LCP, bone tissue and screw geometry model for a specific region. Bone tissue was included in the sub-models because of the contact of bone tissue with the LCP.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eEvaluation\u003c/p\u003e \u003cp\u003eUsing equivalent von Mises stresses, the critical spots on the plate were assessed, and the strain values on the surface of the individual fragments were identified. Strain intensity and Frost\u0026rsquo;s mechanostat hypothesis [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] were used to assess and analyse the mechanical interaction of bone fragments. On the basis of the Frost mechanostat hypothesis, the evaluation was performed on the basis of the strain intensity. The calculation of strain intensity is represented by the following equation:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:{ϵ}_{i}=MAX\\:\\left|\\left({ϵ}_{1}-{ϵ}_{2}\\right),\\left({ϵ}_{2}-{ϵ}_{3}\\right),{(ϵ}_{3}-{ϵ}_{1})\\right|,$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{ϵ}_{i}\\)\u003c/span\u003e\u003c/span\u003e is the strain intensity and where \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{ϵ}_{1}\\)\u003c/span\u003e\u003c/span\u003e, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{ϵ}_{2}\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{ϵ}_{3}\\)\u003c/span\u003e\u003c/span\u003e represent the principal strains. The strain intensity is expressed in the results in terms of\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\:ϵ\\)\u003c/span\u003e\u003c/span\u003e, where \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:0.001ϵ\\)\u003c/span\u003e\u003c/span\u003e = 0.1% [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFinally, the IFM (interfragmentary motion) between the fragments was monitored, which according to previous studies [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], has a positive effect on the healing of bone tissue under certain circumstances. The IFM-Calculator software [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] in the Python development environment was used to determine the IFM.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eFigure \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows the distributions of the equivalent von Mises stresses on the plate for all the solved variants. For variants 1\u0026ndash;3, the highest stress is in the area of locking screw 5 (see details in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). The highest values of the equivalent stress range from 90 MPa to 120 MPa for variant 1. The lowest equivalent stress on the plate is in the case of variant 4, which lacks a locking screw (screw 5) and one screw in the diaphysis of the ulna (screw 7). The maximal equivalent stress is 98 MPa in the area of locking screw 1, which is in the olecranon of the ulna bone.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe results from the sub-model for variants 1\u0026ndash;3 in the locking screw 5 region are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e, and the highest equivalent stress ranges from 200 MPa to 350 MPa for Variant 3. For Variant 4, the highest equivalent stress value is in the locking screw 2 region.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e shows the equivalent strain intensity on the inner surface of the bone fragments. Fragment C near locking screw 5 is the fragment with the highest strain values, as it is the most mechanically loaded. The bone tissues near the screws are slightly overloaded, and the strain is greater than \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:0.003ϵ\\)\u003c/span\u003e\u003c/span\u003e. The highest values of strain intensity in the bone tissues were observed in Variant 4.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe relative displacements are evaluated via IFM and are presented in Figs.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e for the analysed fragments. The highest values of relative displacement are obtained in the case of Fragment A (olecranon), which is 0.041 mm. The highest displacements were always obtained in the case of Variant 4, as well as in the case of strain intensity analysed in bone tissue, and the other variants of screw insertion were comparable.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOlecranon fractures are among the most common upper limb injuries. By definition, they are predominantly intra-articular fractures that have been treated surgically for decades, with the primary goal of achieving optimal functional outcomes. Surgical management typically adheres to the fundamental principles established by expert organisations e.g. the AO Foundation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], which relies heavily on empirical approaches\u0026mdash;likely due to the absence of a universally applicable method. This has led to the development and adoption of various alternative osteosynthesis techniques in addition to two conventionally established methods. Nevertheless, the literature reports a high incidence of complications and secondary surgeries in this context [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Some of these complications are associated with inadequate fracture healing and are often influenced by inappropriate fixation related to the number, direction and length of locking screws used [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn silico experiments using a computational model that incorporates all relevant anatomical and biomechanical parameters may help predict and prevent such complications. In our model, a complex fracture with characteristic fracture lines was intentionally selected [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. This study examined how the number of screws affects LCP loading, bone remodelling, and interfragmentary motion (IFM), with the aim of evaluating and comparing bone healing outcomes. Four screw configuration variants were developed, and comparative biomechanical analyses were performed.\u003c/p\u003e \u003cp\u003eThe equivalent von Mises stress on the LCP was assessed across all the screw configurations. Due to the nature of loading, only static stress was analysed in the neutral postoperative position of the ulna, with high-cycle fatigue being excluded [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The analysis was conducted with respect to the standard healing period of 3\u0026ndash;6 months [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. The Sub-models were used to focus on the regions with the highest stress concentrations. For Variants 1\u0026ndash;3, the maximum stress occurred near locking screw 5. The stress values ranged from 200 MPa to 350 MPa, with the highest observed in Variant 3, where screws 2 and 3\u0026mdash;anchoring the olecranon\u0026mdash;were omitted. In Variant 4, the stress concentration shifted toward the olecranon due to the absence of screw 5, where local plasticisation exceeding 415 MPa was observed in the screw hole region [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe LCP maintains the relative position of the bone fragments [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], allowing slight interfragmentary movement, which generates varying loads on the bone tissue. The equivalent strain intensity results indicate moderate loading of the bone tissue, which is consistent with physiological strain and normal bone remodelling due to fragment interactions. Most strain values ranged from 0.0001 to 0.0015 mm/mm, suggesting a healthy remodelling response. None of the configurations exceeded an equivalent strain of 0.025 mm/mm, which is indicative of pathological bone overloading or potential fracture strain[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e], [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFixation stability was also evaluated through analysis of the IFM. In all the tested configurations, the IFM values suggested sufficient stability for successful fracture healing [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Variants 1\u0026ndash;3 presented comparable IFM values, whereas Variant 4 presented the highest IFM, particularly in the olecranon region (Fragment A), where motion exceeded 0.036 mm. For comparison, Kenwright and Goodship recommended an optimal IFM of 0.2\u0026ndash;1.0 mm in the diaphyseal region to support secondary bone healing [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e], [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e], and Wolf et al. proposed a 0.4 mm threshold in diaphyseal osteotomies where callus formation is also desired [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, few studies have evaluated IFM in periarticular regions where primary bone healing is preferred, as callus formation is typically absent. These studies generally agree that the IFM should not exceed 0.03 mm in such contexts [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Thus, the elevated IFM observed in Variant 4 may compromise primary healing. In contrast, the IFM values in the other configurations fall within acceptable limits, supporting primary bone healing. This finding indicates that the studied construct is not excessively rigid across configurations.\u003c/p\u003e \u003cp\u003eNonetheless, the IFM results highlight the importance of securely fixing the coronoid (Fragment B), as insufficient fixation in this area risks exceeding the critical IFM threshold of 0.02 mm [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e], potentially leading to fragment displacement under load. Similarly, fixation of the apical fragment of the olecranon (Fragment A) is critical and typically ensured by standard plate designs.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study evaluated four fixation variants for comminuted fractures of the proximal ulna, which differ in the number of screws used. The results of the stress and strain analysis revealed several important findings. The use of a 3.5 mm LCP and screws provides sufficient structural stability in this anatomical region. Given the recorded load levels, material failure under normal physiological conditions is unlikely. Therefore, the use of less bulky implants may be both adequate and desirable, as it could reduce patient discomfort related to implant prominence.\u003c/p\u003e \u003cp\u003eThe elevated bone loading around the screws further supports the established principle that screws should not engage directly with fracture lines. On the other hand, IFM analysis revealed that the presence of a coronoid fragment necessitates sufficient fixation with at least one screw to avoid exceeding the critical motion threshold, which could otherwise compromise articular healing or cause fragment detachment under early loading. Similar fixation requirements apply to the apical fragment of the olecranon, although these requirements are typically addressed by standard pre-contoured plate designs.\u003c/p\u003e \u003cp\u003eThe remaining IFM values observed across all the other configurations remained within the range favour able for primary bone healing, indicating that none of the studied constructs are excessively stiff.\u003c/p\u003e \u003cp\u003eFor future applications of this computational model, it would be valuable to compare various osteosynthesis techniques with differing biomechanical characteristics. Such comparative studies should be pursued in further research.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eJ.Š. conceptualization, writing - original draft, investigation, visualization, methodology, writing - review and editing. T.P. conceptualization, writing - original draft, investigation, visualization, methodology, writing - review and editing. P.M. conceptualization, methodology, supervision, writing - review and editing, funding acquisition. R.H. investigation, visualization, methodology. R.V. conceptualization, methodology, supervision.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData is provided within the manuscript or supplementary information files.DOI: 10.5281/zenodo.15155804\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eCourt-Brown CM, Caesar B. \u0026lsquo;Epidemiology of adult fractures: A review\u0026rsquo;, \u003cem\u003eInjury\u003c/em\u003e, vol. 37, no. 8, pp. 691\u0026ndash;697, Aug. 2006, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2006.04.130\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2006.04.130\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDuckworth AD, Clement ND, Aitken SA, Court-Brown CM, McQueen MM. \u0026lsquo;The epidemiology of fractures of the proximal ulna\u0026rsquo;, \u003cem\u003eInjury\u003c/em\u003e, vol. 43, no. 3, pp. 343\u0026ndash;346, Mar. 2012, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2011.10.017\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2011.10.017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWilkerson JA, Rosenwasser MP. Surgical Techniques of Olecranon Fractures. J Hand Surg Am. Aug. 2014;39(8):1606\u0026ndash;14. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhsa.2014.05.014\u003c/span\u003e\u003cspan address=\"10.1016/j.jhsa.2014.05.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTarallo L, Mugnai R, Adani R, Capra F, Zambianchi F, Catani F. \u0026lsquo;Simple and comminuted displaced olecranon fractures: a clinical comparison between tension band wiring and plate fixation techniques\u0026rsquo;, \u003cem\u003eArch Orthop Trauma Surg\u003c/em\u003e, vol. 134, no. 8, pp. 1107\u0026ndash;1114, Aug. 2014, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00402-014-2021-9\u003c/span\u003e\u003cspan address=\"10.1007/s00402-014-2021-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAugat P, Simon U, Liedert A, Claes L. Mechanics and mechano-biology of fracture healing in normal and osteoporotic bone. Osteoporos Int. Mar. 2005;16:S36\u0026ndash;43. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00198-004-1728-9\u003c/span\u003e\u003cspan address=\"10.1007/s00198-004-1728-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKlein P et al. Jul., \u0026lsquo;The initial phase of fracture healing is specifically sensitive to mechanical conditions\u0026rsquo;, \u003cem\u003eJournal of Orthopaedic Research\u003c/em\u003e, vol. 21, no. 4, pp. 662\u0026ndash;669, 2003, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0736-0266(02)00259-0\u003c/span\u003e\u003cspan address=\"10.1016/S0736-0266(02)00259-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMiramini S, Zhang L, Richardson M, Mendis P, Oloyede A, Ebeling P. The relationship between interfragmentary movement and cell differentiation in early fracture healing under locking plate fixation. Australas Phys Eng Sci Med. Mar. 2016;39(1):123\u0026ndash;33. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s13246-015-0407-9\u003c/span\u003e\u003cspan address=\"10.1007/s13246-015-0407-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLubberts B, Mellema JJ, Janssen SJ, Ring D. Fracture line distribution of olecranon fractures. Arch Orthop Trauma Surg. Jan. 2017;137(1):37\u0026ndash;42. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00402-016-2593-7\u003c/span\u003e\u003cspan address=\"10.1007/s00402-016-2593-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMorrey BF. Functional Evaluation of the Elbow. Morrey\u0026rsquo;s the Elbow and its Disorders. Elsevier; 2018. pp. 66\u0026ndash;74. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/B978-0-323-34169-1.00005-X\u003c/span\u003e\u003cspan address=\"10.1016/B978-0-323-34169-1.00005-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHodgson S, \u0026lsquo;AO Principles of Fracture Management\u0026rsquo;. Jul.,, \u003cem\u003eThe Annals of The Royal College of Surgeons of England\u003c/em\u003e, vol. 91, no. 5, pp. 448\u0026ndash;449, 2009, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1308/rcsann.2009.91.5.448b\u003c/span\u003e\u003cspan address=\"10.1308/rcsann.2009.91.5.448b\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarci\u0026aacute;n P et al. Jan., \u0026lsquo;On the level of computational models in biomechanics depending on gained data from CT/MRI and micro-CT\u0026rsquo;, \u003cem\u003eMendel\u003c/em\u003e, pp. 455\u0026ndash;462, 2011.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShepherd DET, Seedhom BB. Thickness of human articular cartilage in joints of the lower limb. Ann Rheum Dis. Jan. 1999;58(1):27\u0026ndash;34. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/ard.58.1.27\u003c/span\u003e\u003cspan address=\"10.1136/ard.58.1.27\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZimmer, Biomet. \u0026lsquo;Zimmer\u0026reg; Universal Locking System\u0026amp;#8217.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ea. s. MEDIN, \u0026lsquo;Catalogues \u0026ndash; MEDIN, a.s.\u0026amp;#8217.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRho JY, Hobatho MC, Ashman RB. Relations of mechanical properties to density and CT numbers in human bone. Med Eng Phys. 1995;17(5):347\u0026ndash;55. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/1350-4533(95)97314-F\u003c/span\u003e\u003cspan address=\"10.1016/1350-4533(95)97314-F\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCowin SC, Sadegh AM. Non-interacting modes for stress, strain and energy in anisotropic hard tissue. J Biomech. 1991;24(9):859\u0026ndash;67. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0021-9290(91)90311-A\u003c/span\u003e\u003cspan address=\"10.1016/0021-9290(91)90311-A\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRho J-Y, Tsui TY, Pharr GM. \u0026lsquo;Elastic properties of human cortical and trabecular lamellar bone measured by nanoindentation\u0026rsquo;, \u003cem\u003eBiomaterials\u003c/em\u003e, vol. 18, no. 20, pp. 1325\u0026ndash;1330, 1997, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0142-9612(97)00073-2\u003c/span\u003e\u003cspan address=\"10.1016/S0142-9612(97)00073-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReilly DT, Burstein AH, Frankel VH. The elastic modulus for bone. J Biomech. 1974;7(3):271\u0026ndash;5. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0021-9290(74)90018-9\u003c/span\u003e\u003cspan address=\"10.1016/0021-9290(74)90018-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePe\u0026ntilde;a E, Calvo B, Mart\u0026iacute;nez MA, Doblar\u0026eacute; M. A three-dimensional finite element analysis of the combined behavior of ligaments and menisci in the healthy human knee joint. J Biomech. 2006;39(9):1686\u0026ndash;701. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jbiomech.2005.04.030\u003c/span\u003e\u003cspan address=\"10.1016/j.jbiomech.2005.04.030\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBevan MA et al. \u0026lsquo;Mechanical Properties and Behavior of Additive Manufactured Stainless Steel 316L\u0026rsquo;, 2017, pp. 577\u0026ndash;583. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/978-3-319-51382-9_63\u003c/span\u003e\u003cspan address=\"10.1007/978-3-319-51382-9_63\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKang L, Chen F, Bradford MA, Liu X. \u0026lsquo;Experimental study of mechanical properties of laser additively manufactured 316L stainless steels\u0026rsquo;, \u003cem\u003eStructures\u003c/em\u003e, vol. 54, pp. 221\u0026ndash;235, Aug. 2023, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.istruc.2023.05.053\u003c/span\u003e\u003cspan address=\"10.1016/j.istruc.2023.05.053\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKusy RP, Dilley GJ. \u0026lsquo;Materials Science Elastic Modulus of a Triple-stranded Stainless Steel Arch Wire via Three- and Four-point Bending\u0026rsquo;, \u003cem\u003eJ Dent Res\u003c/em\u003e, vol. 63, no. 10, pp. 1232\u0026ndash;1240, Oct. 1984, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1177/00220345840630101401\u003c/span\u003e\u003cspan address=\"10.1177/00220345840630101401\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOdegard BC, West AJ. On the thermo-mechanical behavior and hydrogen compatibility of 22-13-5 stainles steel. Mater Sci Eng. Jun. 1975;19(2):261\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/0025-5416(75)90113-5\u003c/span\u003e\u003cspan address=\"10.1016/0025-5416(75)90113-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAydın, T\u0026ouml;zeren. \u0026lsquo;Human Body Dynamics\u0026rsquo;, p., 2000, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/b97432\u003c/span\u003e\u003cspan address=\"10.1007/b97432\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWalpole SC, Prieto-Merino D, Edwards P, Cleland J, Stevens G, Roberts I. The weight of nations: an estimation of adult human biomass. BMC Public Health. Dec. 2012;12(1):439. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/1471-2458-12-439\u003c/span\u003e\u003cspan address=\"10.1186/1471-2458-12-439\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReed J, Bowen JD. Chapter 33 - Principles of Sports Rehabilitation. In: Seidenberg PH, Beutler AI, editors. The Sports Medicine Resource Manual. Philadelphia: W.B. Saunders; 2008. pp. 431\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/B978-141603197-0.10033-3\u003c/span\u003e\u003cspan address=\"10.1016/B978-141603197-0.10033-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarci\u0026aacute;n P, Wolff J, Hor\u0026aacute;čkov\u0026aacute; L, Kaiser J, Zikmund T, Borak L. Micro finite element analysis of dental implants under different loading conditions. Comput Biol Med. Mar. 2018;96. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.compbiomed.2018.03.012\u003c/span\u003e\u003cspan address=\"10.1016/j.compbiomed.2018.03.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrost H. \u0026lsquo;A 2003 update of bone physiology and Wolff\u0026rsquo;s Law for clinicians\u0026rsquo;, \u003cem\u003eAngle Orthod\u003c/em\u003e, vol. 74, pp. 3\u0026ndash;15, Mar. 2004, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1043/0003-3219(2004)074\u0026lt;0003:AUOBPA\u0026gt;2.0.CO;2\u003c/span\u003e\u003cspan address=\"10.1043/0003-3219(2004)074%3C0003:AUOBPA%3E2.0.CO;2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamaji T, Ando K, Wolf S, Augat P, Claes L. The effect of micromovement on callus formation. J Orthop Sci. 2001;6:571\u0026ndash;5. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s007760100014\u003c/span\u003e\u003cspan address=\"10.1007/s007760100014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun J, Wu L, Fang N, Liu L. IFM calculator: An algorithm for interfragmentary motion calculation in finite element analysis. Comput Methods Programs Biomed. 2024;244:107996. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cmpb.2023.107996\u003c/span\u003e\u003cspan address=\"10.1016/j.cmpb.2023.107996\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBethell MA, et al. Complications Associated with Surgical Management of Olecranon Fractures. JBJS Rev. Mar. 2025;13(3). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2106/JBJS.RVW.24.00163\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.RVW.24.00163\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQi H, et al. Comparison of clinical outcomes of three internal fixation techniques in the treatment of olecranon fracture: a retrospective clinical study. BMC Musculoskelet Disord. Dec. 2022;23(1):521. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12891-022-05482-8\u003c/span\u003e\u003cspan address=\"10.1186/s12891-022-05482-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePowell AJ, Farhan-Alanie OM, McGraw IWW. \u0026lsquo;Tension band wiring versus locking plate fixation for simple, two-part Mayo 2A olecranon fractures: a comparison of post-operative outcomes, complications, reoperations and economics\u0026rsquo;, \u003cem\u003eMusculoskelet Surg\u003c/em\u003e, vol. 103, no. 2, pp. 155\u0026ndash;160, Aug. 2019, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s12306-018-0556-6\u003c/span\u003e\u003cspan address=\"10.1007/s12306-018-0556-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNorris BL, Lang G, Russell TA, Rothberg DL, Ricci WM, Borrelli J, editors. \u0026lsquo;Absolute Versus Relative Fracture Fixation: Impact on Fracture Healing\u0026rsquo;, \u003cem\u003eJ Orthop Trauma\u003c/em\u003e, vol. 32, no. 3, pp. S12\u0026ndash;S16, Mar. 2018, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/BOT.0000000000001124\u003c/span\u003e\u003cspan address=\"10.1097/BOT.0000000000001124\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiebenlist S, Torsiglieri T, Kraus T, Burghardt RD, St\u0026ouml;ckle U, Lucke M. \u0026lsquo;Comminuted fractures of the proximal ulna\u0026mdash;Preliminary results with an anatomically preshaped locking compression plate (LCP) system\u0026rsquo;, \u003cem\u003eInjury\u003c/em\u003e, vol. 41, no. 12, pp. 1306\u0026ndash;1311, Dec. 2010, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2010.08.008\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2010.08.008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSumanariu CA, Amza CG, Baciu F, Vasile MI, Nicoara AI. \u0026lsquo;Comparative Analysis of Mechanical Properties: Conventional vs. Additive Manufacturing for Stainless Steel 316L\u0026rsquo;, \u003cem\u003eMaterials\u003c/em\u003e, vol. 17, no. 19, p. 4808, Sep. 2024, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/ma17194808\u003c/span\u003e\u003cspan address=\"10.3390/ma17194808\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTyrovola JB, Odont X. \u0026lsquo;The Mechanostat Theory of Frost and the OPG/RANKL/RANK System\u0026rsquo;, \u003cem\u003eJ Cell Biochem\u003c/em\u003e, vol. 116, no. 12, pp. 2724\u0026ndash;2729, Dec. 2015, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/jcb.25265\u003c/span\u003e\u003cspan address=\"10.1002/jcb.25265\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrost HM. \u0026lsquo;Wolff\u0026rsquo;s Law and bone\u0026rsquo;s structural adaptations to mechanical usage: an overview for clinicians\u0026rsquo;, \u003cem\u003eAngle Orthod\u003c/em\u003e, vol. 64, no. 3, pp. 175\u0026ndash;188, Jun. 1994, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1043/0003-3219(1994)064\u0026lt;0175:WLABSA\u0026gt;2.0.CO;2\u003c/span\u003e\u003cspan address=\"10.1043/0003-3219(1994)064%3C0175:WLABSA%3E2.0.CO;2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePerren SM. \u0026lsquo;Evolution of the internal fixation of long bone fractures: The scientific basis of biological internal fixation: choosing a new balance between stability and biology\u0026rsquo;, \u003cem\u003eJ Bone Joint Surg\u003c/em\u003e, vol. 84, no. 8, pp. 1093\u0026ndash;1110, Nov. 2002, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1302/0301-620X.84B8.13752\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.84B8.13752\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClaes L, Augat P, Suger G, Wilke H. \u0026lsquo;Influence of size and stability of the osteotomy gap on the success of fracture healing\u0026rsquo;, \u003cem\u003eJournal of Orthopaedic Research\u003c/em\u003e, vol. 15, no. 4, pp. 577\u0026ndash;584, Jul. 1997, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/jor.1100150414\u003c/span\u003e\u003cspan address=\"10.1002/jor.1100150414\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKenwright J, \u0026lsquo;EFFECT OF CONTROLLED AXIAL MICROMOVEMENT ON HEALING OF TIBIAL FRACTURES\u0026rsquo;. Nov.,, \u003cem\u003eThe Lancet\u003c/em\u003e, vol. 328, no. 8517, pp. 1185\u0026ndash;1187, 1986, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0140-6736(86)92196-3\u003c/span\u003e\u003cspan address=\"10.1016/S0140-6736(86)92196-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRechter GR, Anthony RT, Rennard J, Kellam JF, Warner SJ. \u0026lsquo;The Impact of Early Axial Interfragmentary Motion on the Fracture Healing Environment: A Scoping Review\u0026rsquo;, \u003cem\u003eInjury\u003c/em\u003e, vol. 55, no. 12, p. 111917, Dec. 2024, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2024.111917\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2024.111917\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWolf S et al. Jun., \u0026lsquo;The effects of external mechanical stimulation on the healing of diaphyseal osteotomies fixed by flexible external fixation\u0026rsquo;, \u003cem\u003eClinical Biomechanics\u003c/em\u003e, vol. 13, no. 4\u0026ndash;5, pp. 359\u0026ndash;364, 1998, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0268-0033(98)00097-7\u003c/span\u003e\u003cspan address=\"10.1016/S0268-0033(98)00097-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarrera I, Gelber PE, Chary G, Gonz\u0026aacute;lez-Ballester MA, Monllau JC, Noailly J. Fixation of a split fracture of the lateral tibial plateau with a locking screw plate instead of cannulated screws would allow early weight bearing: a computational exploration. Int Orthop. Oct. 2016;40(10):2163\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00264-015-3106-y\u003c/span\u003e\u003cspan address=\"10.1007/s00264-015-3106-y\" 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":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6596375/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6596375/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigated the biomechanical behavior of four different screw configurations used to fix comminuted proximal ulna fractures with a locking compression plate (LCP), via a detailed finite element model based on realistic anatomical geometry. The model incorporated both cortical and cancellous bone, soft tissue constraints, and loading conditions to represent the physiological self-weight of the forearm. The stress distribution on the plate, strain intensity within the bone tissue, and interfragmentary motion (IFM) between fracture fragments were evaluated for each configuration. The results indicate that all the tested configurations provide adequate stability under normal loading conditions, with no risk of material failure. However, excessive stress concentrations were observed in specific screw regions depending on the configuration, particularly when screws anchoring the olecranon were omitted. Strain analysis revealed moderate physiological bone loading across variants, whereas IFM assessment highlighted the importance of securing the coronoid and apical fragments to prevent compromised healing. These findings suggest that reduced use of osteosynthetic material may be sufficient for fracture stabilisation, potentially minimising implant-related complications. This modelling approach offers a valuable tool for preclinical assessment of osteosynthesis strategies and supports future comparative research on fixation methods with varying biomechanical properties.\u003c/p\u003e","manuscriptTitle":"Analysing plate fixation of a comminuted fracture of the proximal ulna in relation to the elbow joint: A finite element study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-09 07:09:26","doi":"10.21203/rs.3.rs-6596375/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-05-20T02:00:01+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-19T18:17:33+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-19T10:10:49+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-17T01:20:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-13T21:28:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"229891399578112127250915485927175361055","date":"2025-05-12T01:56:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"246213166752198682557441298142784872605","date":"2025-05-10T16:47:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"7212840692504948630792405737519149337","date":"2025-05-08T12:04:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"301614580636401876032598932384506603842","date":"2025-05-07T06:43:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"228964930827693116062494187827756353592","date":"2025-05-06T14:14:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"155999640050416142327868201954426946601","date":"2025-05-06T09:38:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"323853085000410906242499850533392281645","date":"2025-05-06T08:06:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"338655440757710957586202138601715618780","date":"2025-05-06T06:14:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"175594322290108399326499243306014182179","date":"2025-05-06T06:13:50+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-06T06:01:42+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-06T03:37:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-06T02:20:53+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Orthopaedic Surgery and Research","date":"2025-05-05T17:06:53+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1aba09a7-7d87-45f1-bc67-63e14eeb9692","owner":[],"postedDate":"May 9th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-08-04T16:45:18+00:00","versionOfRecord":{"articleIdentity":"rs-6596375","link":"https://doi.org/10.1186/s13018-025-06031-4","journal":{"identity":"journal-of-orthopaedic-surgery-and-research","isVorOnly":false,"title":"Journal of Orthopaedic Surgery and Research"},"publishedOn":"2025-07-28 16:21:37","publishedOnDateReadable":"July 28th, 2025"},"versionCreatedAt":"2025-05-09 07:09:26","video":"","vorDoi":"10.1186/s13018-025-06031-4","vorDoiUrl":"https://doi.org/10.1186/s13018-025-06031-4","workflowStages":[]},"version":"v1","identity":"rs-6596375","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6596375","identity":"rs-6596375","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}