A Novel Internal Fixation Design for the Treatment of AO/OTA-31A3.3 Intertrochanteric Fractures: Finite Element Analysis

Abstract

Objective: AO/OTA 31-A3.3 intertrochanteric fracture is the most unstable type of intertrochanteric fracture, with a high rate of postoperative complications and implant failure. We have designed a new intramedullary fixation, proximal femoral totally bionic nail (PFTBN), for the treatment of A3.3 intertrochanteric fracture. To test its biomechanical performance, we adopted the method of finite element analysis and compared PFTBN with proximal femoral nail antirotation (PFNA) and proximal femoral bionic nail (PFBN, another internal fixation we previously designed for stable intertrochanteric fractures).

Methods: Mimics, 3-matic, ANSYS, and other software were used to construct a highly precise and realistic 3D digital model of the human femur. An AO/OTA 31-A3.3 intertrochanteric fracture of the femur was constructed according to the 2018 classification of AO/OTA, and then assembled with PFNA, PFBN and PFTBN models, respectively. The stress distribution and displacement distribution of the three groups of constructs were tested under three times the body weight load and one-foot standing configuration.

Results: In terms of maximum stress and maximum displacement, the PFTBN group outperforms the PFBN group, and the PFBN group, in turn, surpasses the PFNA group. The maximum stress of PFTBN group was 408.5 Mpa, that of PFBN group was 525.4 MPa, and that of PFNA group was 764.3 Mpa. Comparatively, the maximum stress in the PFTBN group was reduced by 46.6% when contrasted with the PFNA group. Moreover, the stress dispersion within the PFTBN group was more evenly distributed than PFNA group. Regarding maximum displacement, the PFTBN group displayed the least displacement at 5.15 mm, followed by the PFBN group at 7.32 mm, and the PFNA group at 7.73 mm. Notably, the maximum displacement of the PFTBN group was 33.4% less than that observed in the PFNA group. Additionally, the relative displacement between the fragment and implant at the tip of pressure screw or helical blade was 0.22 mm in the PFTBN group, 0.34 mm in the PFBN group, and substantially higher 0.51 mm in the PFNA group.

Conclusion: The “lever-reconstruction-balance” theory provides a new perspective for us to understand the mechanical conduction of the proximal femur. Compared with PFNA, in treating A3.3 intertrochanteric fractures PFTBN can better reconstruct the function of lateral wall, restore physiological mechanical conduction, increase postoperative stability, and finally reduce the risk of postoperative cut-out and implant failure. It might be a better alternative for the treatment of A3.3 intertrochanteric fracture.

Keywords

Finite element analysis / Internal fixation / Intertrochanteric fracture / Lateral wall / Proximal femoral totally bionic nail

References

[1] Cheung CL, Ang SB, Chadha M. An updated hip fracture projection in Asia: the Asian Federation of Osteoporosis Societies study. Osteoporos Sarcopenia. 2018; 4(1): 16–21.

[2] Lin X, Xiong D, Peng YQ. Epidemiology and management of osteoporosis in the People’s Republic of China: current perspectives. Clin Interv Aging. 2015; 10: 1017–1033.

[3] Hawley S, Dela S, Burton A. Incidence and number of fragility fractures of the hip in South Africa: estimated projections from 2020 to 2050. Osteoporos Int. 2022; 33(12): 2575–2583.

[4] Park JW, Ha YC, Kim JW. The Korean hip fracture registry study. BMC Musculoskelet Disord. 2023; 24(1): 449.

[5] Tsabasvi M, Davey S, Temu R. Hip fracture pattern at a major Tanzanian referral hospital: focus on fragility hip fractures. Arch Osteoporos. 2017; 12(1): 47.

[6] Tan WL, Low SL, Shen L. Osteoporotic hip fractures: 10-year review in a Singaporean hospital. J Orthop Surg (Hong Kong). 2015; 23(2): 150–154.

[7] Alpantaki K, Papadaki C, Raptis K. Gender and age differences in hip fracture types among elderly: a retrospective cohort study. Maedica (Bucur). 2020; 15(2): 185–190.

[8] Surís X, Rodríguez C, Llargués E. Trend and seasonality of hip fractures in Catalonia, Spain: exploring the influence of climate. Calcif Tissue Int. 2024.

[9] Baghdadi S, Kiyani M, Kalantar SH. Mortality following proximal femoral fractures in elderly patients: a large retrospective cohort study of incidence and risk factors. BMC Musculoskelet Disord. 2023; 24(1): 693.

[10] Haentjens P, Autier P, Barette M. Survival and functional outcome according to hip fracture type: a one-year prospective cohort study in elderly women with an intertrochanteric or femoral neck fracture. Bone. 2007; 41(6): 958–964.

[11] Jegathesan T, Kwek EBK. Are intertrochanteric fractures evolving? Trends in the elderly population over a 10-year period. Clin Orthop Surg. 2022; 14(1): 13–20.

[12] Hongku N, Woratanarat P, Nitiwarangkul L. Fracture fixation versus hemiarthroplasty for unstable intertrochanteric fractures in elderly patients: a systematic review and network meta-analysis of randomized controlled trials. Orthop Traumatol Surg Res. 2022; 108(1): 102838.

[13] Kregor PJ, Obremskey WT, Kreder HJ. Unstable pertrochanteric femoral fractures. J Orthop Trauma. 2014; 28(Suppl 8): S25–S28.

[14] Xie H, Wang Z, Zhang J. Clinical outcome of dynamic hip locking plates and proximal femoral nails anti-rotation-Asia for treating intertrochanteric femur fracture with lateral wall fractures in the elder patients. Oncotarget. 2017; 8(47): 82700–82704.

[15] Yu X, Wang H, Duan X. Intramedullary versus extramedullary internal fixation for unstable intertrochanteric fracture, a meta-analysis. Acta Orthop Traumatol Turc. 2018; 52(4): 299–307.

[16] Andalib A, Etemadifar M, Yavari P. Clinical outcomes of intramedullary and extramedullary fixation in unstable intertrochanteric fractures: a randomized clinical trial. Arch Bone Jt Surg. 2020; 8(2): 190–197.

[17] Zhang WQ, Sun J, Liu CY. Comparing the intramedullary nail and extramedullary fixation in treatment of unstable intertrochanteric fractures. Sci Rep. 2018; 8(1): 2321.

[18] Fu CW, Chen JY, Liu YC. Dynamic hip screw with trochanter-stabilizing plate compared with proximal femoral nail antirotation as a treatment for unstable AO/OTA 31-A2 and 31-A3 intertrochanteric fractures. Biomed Res Int. 2020; 2020: 1896935.

[19] Arirachakaran A, Amphansap T, Thanindratarn P. Comparative outcome of PFNA, gamma nails, PCCP, Medoff plate, LISS and dynamic hip screws for fixation in elderly trochanteric fractures: a systematic review and network meta-analysis of randomized controlled trials. Eur J Orthop Surg Traumatol. 2017; 27(7): 937–952.

[20] Gotfried Y. The lateral trochanteric wall: a key element in the reconstruction of unstable pertrochanteric hip fractures. Clin Orthop Relat Res. 2004; 425: 82–86.

[21] Palm H, Jacobsen S, Sonne-Holm S. Integrity of the lateral femoral wall in intertrochanteric hip fractures: an important predictor of a reoperation. J Bone Joint Surg Am. 2007; 89(3): 470–475.

[22] Hsu CE, Shih CM, Wang CC. Lateral femoral wall thickness. A reliable predictor of post-operative lateral wall fracture in intertrochanteric fractures. Bone Joint J. 2013; 95-B(8): 1134–1138.

[23] Ciufo DJ, Zaruta DA, Lipof JS. Risk factors associated with cephalomedullary nail cutout in the treatment of trochanteric hip fractures. J Orthop Trauma. 2017; 31(11): 583–588.

[24] Guerra MTE, Giglio L, Leite BC. Pantrochanteric fracture: incidence of the complication in patients with trochanteric fracture treated with dynamic hip screw in a hospital of southern Brazil. Rev Bras Ortop (Sao Paulo). 2019; 54(1): 64–68.

[25] Kulkarni SG, Babhulkar SS, Kulkarni SM. Augmentation of intramedullary nailing in unstable intertrochanteric fractures using cerclage wire and lag screws: a comparative study. Injury. 2017; 48(Suppl 2): S18–S22.

[26] Wang R, Zhang H, Wei Q. Intramedullary nails in combination with reconstruction plate in the treatment of unstable intertrochanteric femoral fractures with lateral wall damage. Int Orthop. 2021; 45(11): 2955–2962.

[27] Jain S, Dawar H, Khare H. Does augmentation of intramedullary nails by a buttress plate effectively restore lateral wall integrity in intertrochanteric fractures. Int Orthop. 2022; 46(10): 2365–2371.

[28] Chen Y, Liu S, Lin P. Comparative biomechanical study of reversed less invasive stabilization system and proximal femoral nail antirotation for unstable intertrochanteric fractures. Chin Med J (Engl). 2014; 127(23): 4124–4129.

[29] Dy Z. Reviewing the past and future of internal fixation for femoral intertrochanteric fractures based on fulcrum reconstruction theory. Chin J Orthop Trauma. 2020; 22(10): 841–845.

[30] Lotz JC, Cheal EJ, Hayes WC. Stress distributions within the proximal femur during gait and falls: implications for osteoporotic fracture. Osteoporos Int. 1995; 5(4): 252–261.

[31] Nishiyama KK, Gilchrist S, Guy P. Proximal femur bone strength estimated by a computationally fast finite element analysis in a sideways fall configuration. J Biomech. 2013; 46(7): 1231–1236.

[32] Nawathe S, Nguyen BP, Barzanian N. Cortical and trabecular load sharing in the human femoral neck. J Biomech. 2015; 48(5): 816–822.

[33] Enns-Bray WS, Owoc JS, Nishiyama KK. Mapping anisotropy of the proximal femur for enhanced image based finite element analysis. J Biomech. 2014; 47(13): 3272–3278.

[34] Tobin WJ. The internal architecture of the femur and its clinical significance; the upper end. J Bone Joint Surg Am. 1955; 37-A(1): 57–72. passim.

[35] Wolff J. The Law of Bone Remodelling. Vol XII. Berlin: Springer; 1986. p. 126.

[36] Louna Z, Goda I, Ganghoffer JF. Identification of a constitutive law for trabecular bone samples under remodeling in the framework of irreversible thermodynamics. Contin Mech Thermodyn. 2018; 30(3): 529–551.

[37] Hammer A. The paradox of Wolff’s theories. Ir J Med Sci. 2015; 184(1): 13–22.

[38] Skubich J, Piszczatowski S. Model of loadings acting on the femoral bone during gait. J Biomech. 2019; 87: 54–63.

[39] Zhang L, Zhu B, Chen L. The impact of coronal configuration of the proximal femur on its mechanical properties and the validation of a new theoretical model: finite element analysis and biomechanical examination. Orthop Surg. 2023; 15(1): 62–69.

[40] Wang Y, Chen W, Zhang L. Finite element analysis of proximal femur bionic nail (PFBN) compared with proximal femoral nail antirotation and InterTan in treatment of intertrochanteric fractures. Orthop Surg. 2022; 14(9): 2245–2255.

[41] Chen P, Fan Z, Xu N. A biomechanical investigation of a novel intramedullary nail used to salvage failed internal fixations in intertrochanteric fractures. J Orthop Surg Res. 2023; 18(1): 632.

[42] Park SY, Yang KH, Yoo JH. The treatment of reverse obliquity intertrochanteric fractures with the intramedullary hip nail. J Trauma. 2008; 65(4): 852–857.

[43] Fan J, Xu X, Zhou F. The lateral femoral wall thickness on the risk of post-operative lateral wall fracture in intertrochanteric fracture after DHS fixation: a finite element analysis. Injury. 2022; 53(2): 346–352.

[44] Marmor M, Liddle K, Pekmezci M. The effect of fracture pattern stability on implant loading in OTA type 31-A2 proximal femur fractures. J Orthop Trauma. 2013; 27(12): 683–689.

[45] Do JH, Kim YS, Lee SJ. Influence of fragment volume on stability of 3-part intertrochanteric fracture of the femur: a biomechanical study. Eur J Orthop Surg Traumatol. 2013; 23(4): 371–377.

[46] Warschawski Y, Ankori R, Rutenberg TF. Expandable proximal femoral nail versus gamma proximal femoral nail for the treatment of hip reverse oblique fractures. Arch Orthop Trauma Surg. 2022; 142(5): 777–785.

[47] Ren H, Ao R, Wu L. Effect of lesser trochanter posteromedial wall defect on the stability of femoral intertrochanteric fracture using 3D simulation. J Orthop Surg Res. 2020; 15(1): 242.

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2024 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.