Femoral neck fractures necessitate effective fracture fixation techniques to ensure optimal outcomes. The study evaluates the bone remodelling around Dynamic Hip Screw with anti-rotational screw (DHS + AR) and Femoral Neck System (FNS) used for treating femoral neck fractures of Pauwels types I, II and III. Femur models were developed using CT imaging data. Fractures were modelled assuming smooth fracture surfaces. Isotropic heterogeneous CT-grey value-based bone material properties were employed in the bone model, and Ti-alloy was incorporated as implant material. Bone remodelling algorithm based on strain energy density was employed to predict the implants’ effects under two loading conditions: normal walking and stair climbing. The density change (Δρ) was iteratively updated until convergence occurred (Δρ < 0.005 g/cm3 between two consecutive iterations). The investigation compared post-operative (PO) conditions with equilibrium (AE) states. Results revealed that strain shielding was approximately 27% lower in FNS-implanted models than DHS + AR models, indicating better biomechanical performance under adopted modelling assumptions. From PO to AE, axial deformation and rotational stability of the femoral head were reduced more in FNS models, with reductions of up to 13.57% and 83%, respectively. Micromotion was (below 100 μm) in all models except for FNS in Pauwels III fractures under PO conditions. However, it was reduced below 100 μm at AE. Lower bone loss was observed in FNS-implanted models while DHS + AR implanted models exhibited higher resorption. These findings suggest that FNS implants are predicted to provide better stability and favourable bone remodelling outcomes compared to DHS + AR screws.
RidzwanMIZSukjamsriCPalB, et al. Femoral fracture type can be predicted from femoral structure: a finite element study validated by digital volume correlation experiments. J Orthop Res2018; 36: 993–1001. https://doi.org/10.1002/jor.23669
2.
LiJZhaoZYinP, et al. Comparison of three different internal fixation implants in treatment of femoral neck fracture-a finite element analysis. J Orthop Surg Res2019; 14: 76–78. https://doi.org/10.1186/s13018-019-1097-x
SendtnerERenkawitzTKramnyP, et al. Fractured neck of femur—internal fixation versus arthroplasty. Deutsches Aerzteblatt International2010; 107: 401. https://doi.org/10.3238/arztebl.2010.0401
5.
ChaY-HYooJ-IHwangS-Y, et al. Biomechanical evaluation of internal fixation of Pauwels type III femoral neck fractures: a systematic review of various fixation methods. Clin Orthop Surg2019; 11: 1–14. https://doi.org/10.4055/cios.2019.11.1.1
6.
HuangSZhangYZhangX, et al. Comparison of femoral neck system and three cannulated cancellous screws in the treatment of vertical femoral neck fractures: clinical observation and finite element analysis. Biomed Eng Online2023; 22: 20. https://doi.org/10.1186/s12938-023-01083-1
7.
LimEJShonH-CChoJ-W, et al. Dynamic hip screw versus cannulated cancellous screw in Pauwels type II or type III femoral neck fracture: a systematic review and meta-analysis. J Pers Med2021; 11: 1017. https://doi.org/10.3390/jpm11101017
8.
MahapatraBPalB. Biomechanical analysis of various internal fracture fixation devices used for treating femoral neck fractures: A comparative finite element analysis. Injury2024; 55: 111717. https://doi.org/10.1016/j.injury.2024.111717
9.
FreitasAToledo JúniorJVFerreira Dos SantosA, et al. Biomechanical study of different internal fixations in Pauwels type III femoral neck fracture - a finite elements analysis. J Clin Orthop Trauma2021; 14: 145–150. https://doi.org/10.1016/j.jcot.2020.06.006
10.
MahapatraBPalB. From healthy to osteoporotic: Exploring how bone quality alters implant performance in Pauwels type III fracture. Proc Inst Mech Eng2025; 239(5): 436–447. https://doi.org/10.1177/09544119251333671
11.
XuZSunJLiJ, et al. Comparative analysis of the femoral neck system (FNS) vs. Cannulated cancellous screws (CCS) in the treatment of middle-aged and elderly patients with femoral neck fractures: clinical outcomes and biomechanical insights. BMC Musculoskelet Disord2024; 25: 735. https://doi.org/10.1186/s12891-024-07863-7
12.
GuoCHuangJChenZ, et al. Clinical efficacy of femoral neck system for treatment of unstable femoral neck fractures in young adults. J Int Med Res2024; 52: 03000605241238983. https://doi.org/10.1177/03000605241238983
13.
VazquezOGamulinAHannoucheD, et al. Osteosynthesis of non-displaced femoral neck fractures in the elderly population using the femoral neck system (FNS): short-term clinical and radiological outcomes. J Orthop Surg Res2021; 16: 477–479. https://doi.org/10.1186/s13018-021-02622-z
14.
NanCMaLLiangY, et al. Mechanical effects of sagittal variations on Pauwels type III femoral neck fractures treated with Femoral Neck System(FNS). BMC Musculoskelet Disord2022; 23: 1045. https://doi.org/10.1186/s12891-022-06016-y
15.
SunXHanZCaoD, et al. Finite element analysis of six internal fixations in the treatment of Pauwels type III femoral neck fracture. Orthop Surg2024; 16: 1695–1709. https://doi.org/10.1111/os.14069
16.
CuiHWeiWShaoY, et al. Finite element analysis of fixation effect for femoral neck fracture under different fixation configurations. Comput Methods Biomech Biomed Eng2022; 25: 132–139. https://doi.org/10.1080/10255842.2021.1935899
17.
IupparielloLEspositoLGargiuloP, et al. A CT-based method to compute femur remodelling after total hip arthroplasty. Comput Methods Biomech Biomed Eng Imaging Vis2021; 9: 428–437. https://doi.org/10.1080/21681163.2020.1835540
18.
MathaiBDharaSGuptaS. Bone remodelling in implanted proximal femur using topology optimization and parameterized cellular model. J Mech Behav Biomed Mater2022; 125: 104903. https://doi.org/10.1016/j.jmbbm.2021.104903
19.
PalBGuptaS. The effect of primary stability on load transfer and bone remodelling within the uncemented resurfaced femur. Proc Inst Mech Eng H2011; 225: 549–561. https://doi.org/10.1177/0954411910397102
20.
LohaTBhattacharyaRPalB, et al. A novel design of hip-stem with reduced strain-shielding. Proc Inst Mech Eng H2024; 238: 471–482. https://doi.org/10.1177/09544119241244537
21.
Al-HajajZAvvalPTBougheraraH. Computational prediction of the long-term behavior of the femoral density after THR using the silent hip stem. Comput Methods Biomech Biomed Eng2023; 26: 373–382. https://doi.org/10.1080/10255842.2022.2064712
22.
HaiderITSpeirsADBeauléPE, et al. Influence of ingrowth regions on bone remodelling around a cementless hip resurfacing femoral implant. Comput Methods Biomech Biomed Eng2015; 18: 1349–1357. https://doi.org/10.1080/10255842.2014.903931
23.
MorganEFBayraktarHHKeavenyTM. Trabecular bone modulus-density relationships depend on anatomic site. J Biomech2003; 36: 897–904.
24.
ChandaSGuptaSPratiharDK. A combined neural network and genetic algorithm based approach for optimally designed femoral implant having improved primary stability. Appl Soft Comput2016; 38: 296–307.
25.
RaoLMittalSTrikhaV, et al. Failure of femoral neck system in Pauwels type III fracture: a fractography and finite element study. Mater Des2025; 260: 114964.
26.
LohaTMukherjeeKPalB. Prediction of bone ingrowth into a porous novel hip-stem: A finite element analysis integrated with mechanoregulatory algorithm. Proc Inst Mech Eng H2024; 238: 992–1004. https://doi.org/10.1177/09544119241286958
27.
GuptaSvan der HelmFCSterkJC, et al. Development and experimental validation of a three-dimensional finite element model of the human scapula. Proc Inst Mech Eng H2004; 218: 127–142. https://doi.org/10.1243/095441104322984022
28.
RadcliffeIATaylorM. Investigation into the effect of varus-valgus orientation on load transfer in the resurfaced femoral head: a multi-femur finite element analysis. Clin Biomech2007; 22: 780–786. https://doi.org/10.1016/j.clinbiomech.2007.03.011
29.
RadcliffeIATaylorM. Investigation into the affect of cementing techniques on load transfer in the resurfaced femoral head: a multi-femur finite element analysis. Clin Biomech2007; 22: 422–430. https://doi.org/10.1016/j.clinbiomech.2006.12.001
HellerMOBergmannGDeuretzbacherG, et al. Musculo-skeletal loading conditions at the hip during walking and stair climbing. J Biomech2001; 34: 883–893. https://doi.org/10.1016/S0021-9290(01)00039-2
32.
SinghAPRanaMPalB, et al. Patient-specific femoral implant design using metamaterials for improving load transfer at proximal-lateral region of the femur. Med Eng Phys2023; 113: 103959. https://doi.org/10.1016/j.medengphy.2023.103959
33.
WeinansHHuiskesRvan RietbergenB, et al. Adaptive bone remodeling around bonded noncemented total hip arthroplasty: a comparison between animal experiments and computer simulation. J Orthop Res1993; 11: 500–513. https://doi.org/10.1002/jor.1100110405
34.
FrostHM. The laws of bone structure. springfield il. Charles C Thomas, 1964.
35.
HuiskesRWeinansHGrootenboerHJ, et al. Adaptive bone-remodeling theory applied to prosthetic-design analysis. J Biomech1987; 20: 1135–1150.
36.
SamsamiSSaberiSSadighiS, et al. Comparison of three fixation methods for femoral neck fracture in young adults: Experimental and numerical investigations. J Med Biol Eng2015; 35: 566–579. https://doi.org/10.1007/s40846-015-0085-9
37.
ReimeringerMNuñoNDesmarais-TrépanierC, et al. The influence of uncemented femoral stem length and design on its primary stability: a finite element analysis. Comput Methods Biomech Biomed Eng2013; 16: 1221–1231. https://doi.org/10.1080/10255842.2012.662677
38.
ten BroekeRHMTaralaMArtsJJ, et al. Improving peri-prosthetic bone adaptation around cementless hip stems: a clinical and finite element study. Med Eng Phys2014; 36: 345–353.
39.
ChungHKimYKookI, et al. Comparative short-term outcomes of femoral neck system (FNS) and cannulated screw fixation in patients with femoral neck fractures: a multicenter study. Clin Orthop Surg2024; 16: 184–193. https://doi.org/10.4055/cios23190
40.
LinHLaiCZhouZ, et al. Femoral neck system vs. four cannulated screws in the treatment of Pauwels III femoral neck fracture. J Orthop Sci2023; 28: 1373–1378. https://doi.org/10.1016/j.jos.2022.09.006
41.
StassenRCJeukenRMBoonenB, et al. First clinical results of 1-year follow-up of the femoral neck system for internal fixation of femoral neck fractures. Arch Orthop Trauma Surg2022; 142: 3755–3763. https://doi.org/10.1007/s00402-021-04216-0
42.
NiemannMMaleitzkeTJahnM, et al. Restoration of hip geometry after femoral neck fracture: a comparison of the femoral neck system (FNS) and the dynamic hip screw (DHS). Life2023; 13: 2073. https://doi.org/10.3390/life13102073
43.
MondalSGhoshR. Bone remodelling around the tibia due to total ankle replacement: effects of implant material and implant-bone interfacial conditions. Comput Methods Biomech Biomed Eng2019; 22: 1247–1257. https://doi.org/10.1080/10255842.2019.1661385
44.
LerchMKurtzAStukenborg-ColsmanC, et al. Bone remodeling after total hip arthroplasty with a short stemmed metaphyseal loading implant: finite element analysis validated by a prospective DEXA investigation. J Orthop Res2012; 30: 1822–1829. https://doi.org/10.1002/jor.22120
45.
TurnerAWGilliesRMSekelR, et al. Computational bone remodelling simulations and comparisons with DEXA results. J Orthop Res2005; 23: 705–712. https://doi.org/10.1016/j.orthres.2005.02.002
46.
SchileoETaddeiFMalandrinoA, et al. Subject-specific finite element models can accurately predict strain levels in long bones. J Biomech2007; 40: 2982–2989. https://doi.org/10.1016/j.jbiomech.2007.02.010
47.
PengLBaiJZengX, et al. Comparison of isotropic and orthotropic material property assignments on femoral finite element models under two loading conditions. Med Eng Phys2006; 28: 227–233.
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
