Three-dimensional finite element analysis on intramedullary controlled dynamic nailing for femoral shaft fracture

doi:10.3969/j.issn.2095-4344.2014.40.022

Abstract

Abstract:

BACKGROUND: Interlocking intramedullary nail complications contain nail bent or broken, exit, re-fracture at spiketail or nail hole. Thus, our team designs a novel intramedullary controlled dynamic nail.

OBJECTIVE: To evaluate the rationality and safety of intramedullary controlled dynamic nail design and strength, and to give rational proposal for its clinical application.

METHODS: The three-dimensional finite element models of composite femur, transverse fractures of the femoral shaft were constructed with intramedullary controlled dynamic nailing. The stress and strain were detected under vertical loads and gait cycle.

RESULTS AND CONCLUSION: The maximum stress of the intact femur under the compression load was at femoral neck and the medial and lateral aspects of the femoral shaft; while the stresses of fractured femur were at the interface between screw and screw hole. In gait cycle, in case of intact bone, large stresses were found in the distal 1/2 of anteriomedialis of femoral shaft; while the stress distribution in fractured femur was similar with the former. Intramedullary controlled dynamic nailing has the ability of generating compression between fragments. These suggest that intramedullary controlled dynamic nailing is rational and good at design and biomechanical properties.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

全文链接：

Key words: femoral fractures, fractures, stress, bone nails, finite element analysis

CLC Number:

R318

Wang Guo-dong, Jiang Hai-bo, Zhang Yuan-min, Zhao Xiao-wei, Pan Tao. Three-dimensional finite element analysis on intramedullary controlled dynamic nailing for femoral shaft fracture[J]. Chinese Journal of Tissue Engineering Research, 2014, 18(40): 6524-6530.

Figures/Tables 3

2.1 髓内持骨动力性髓内钉固定股骨干骨折的有限元模型实验论证有限元模型和实验计算结果一致性良好(图2)。因此，有限元模型的建立是可信的。 2.2 髓内持骨动力性髓内钉固定股骨干骨折的应力分布 2.2.1 骨表面的应力分布完整股骨在不同的垂直载荷下的应力分布，应力分布区以股骨颈部及股骨干内外侧缘较明显，随着载荷的增加股骨上的应力峰值也逐渐增大；骨折髓内固定后，应力主要集中在股骨颈(髓内钉的顶端以及股骨颈下部)和锁钉周围，随着载荷的增加股骨上的应力峰值也逐渐增大(图3)。对比置入髓内钉之前的图片，股骨干没有明显的应力集中区。应力值较骨折之前减少，由此可以看出，骨折之后，部分负荷经髓内钉承担，同时髓内钉最大应力值较骨折之前增大。模拟人体在步态运动中不同时刻的应力分布。完整股骨30%步态时所受到的应力峰值较大，主要集中在股骨远端1/2前内侧，在股骨颈下部也有应力较大区的存在；在45% 步态时最小，而应力分部区较分散，几乎波及整个股骨干前内侧及股骨颈下部；骨折髓内固定后，仅在髓内钉顶端及锁钉周围有较高的应力集中(图4A)。与承受压缩负荷不同的是骨折之后，股骨表面的应力最大(图4B)。完整股骨髓内固定骨折后，为了详细显示其应力分布情况，将应力值的数量级缩小。髓内固定后的股骨近段，股骨颈依然是应力集中区，同时锁钉孔也是应力集中区；而股骨远端，股骨受到的峰值应力作用于股骨的内侧(图5)。 2.2.2 髓内钉表面的应力分布对比骨折愈合前后髓内钉的应力变化图(用完整股骨植入髓内钉模拟骨折愈合)，愈合之前髓内钉承受的应力大于骨折愈合后的，而应力分部区在骨折愈合前后并无明显差异，主要集中髓内钉/锁钉界面周围、拉力螺母周围及撑开部，另外在髓内钉撑开部与钉干的结合部分也是应力的高集中区(图6)。 2.3 髓内钉及骨的位移承受压缩负荷时，髓内钉及骨上的位移随负荷的增大逐渐增大，在一定范围内呈线性趋势，而在相等的负荷下，完整骨植入髓内钉后的位移最小，其次是完整骨，完整骨植入髓内钉后骨折的位移最大。由位移-负荷曲线所示，添加趋势线之后均呈线性，而且曲线延长之后恰好通过坐标轴原点，故在承受最大负荷2 100 N时，3种模型的力-变形曲线仍呈线性趋势，即模型在承受 2 100 N的负荷时，仍在其弹性区承受负荷，去除负荷后，模型可以回复到原来的形状(图7)。此与生物力学实验的结果相符(生物力学实验证实，在承受700 N的垂直负荷时，骨折后材料的变形为41.2×10-5 mm)[23]，进一步证实了有限元模型建立的准确性。此前的生物力学实验同时也表明，在承受扭转和弯曲负荷时，形变仍然很小(承受300 N扭转负荷时为0.42 mm；承受8 N•m的弯曲负荷时为19°；与交锁髓内钉相比差异并无统计学意义)[23]。 2.4 断端动力性加压作用在不同的步态以及不同的垂直载荷下均可以看到，骨折远端毗邻骨折线处存在明显的应力集中点(图5右)，而骨折近端毗邻骨折线处往往是近端应力最小处(图5左)。但是这里要提醒注意的是，两图的数量级是不同的，近端的应力最小值仍然大于远端的应力最大值，应力差随之产生。由图8可以看到，不同负荷下骨折端的应力差呈曲线趋势，整体走向随负荷的增大逐渐增大： σ= (F2+3F+0.8)×10-6(R2=0.996 9)(σ应力，F负荷) 这与生物力学实验的结果相类似(生物力学实验证实，承受700 N的负荷下，骨折端的应力值为7.8×10-6 N/mm2)[23]。由图6也可以看出，拉力螺母所在的部位及撑开部存在高应力区，这就是动力加压的产生原因。"

References

[1] Lin J, Lin SJ, Chen PQ, et al. Stress analysis of the distal locking screws for femoral interlocking nailing. J Orthop Res. 2001;19(1):57-63.
[2] Piccioli A, Rossi B, Scaramuzzo L, et al. Intramedullary nailing for treatment of pathologic femoral fractures due to metastases. Injury. 2014;45(2):412-417.
[3] Gavaskar AS, Chowdary N. Blocking screws: an adjunct to retrograde nailing for distal femoral shaft fractures. J Orthop Surg (Hong Kong). 2013;21(2):158-162.
[4] Sadic S, Custovic S, Smajic N, et al. Complications and functional recovery in treatment of femoral shaft fractures with unreamed intramedullary nailing. Med Arch. 2014;68(1): 30-33.
[5] Kesemenli CC, Tosun B, Kim NS. A comparison of intramedullary nailing and plate-screw fixation in the treatment for ipsilateral fracture of the hip and femoral shaft. Musculoskelet Surg. 2012;96(2):117-124.
[6] Akinyoola L, Orekha O, Odunsi A. Open intramedullary nailing of neglected femoral shaft fractures: indications and outcome. Acta Orthop Belg. 2011;77(1):73-77.
[7] Ozdemir B, Akesen B, Demira? B, et al. Long-term outcome of unreamed intramedullary nails in femur diaphyseal fractures. Ulus Travma Acil Cerrahi Derg. 2012;18(2): 147-152.
[8] Crosby SN Jr, Kim EJ, Koehler DM, et al. Twenty-Year Experience with Rigid Intramedullary Nailing of Femoral Shaft Fractures in Skeletally Immature Patients. J Bone Joint Surg Am. 2014;96(13):1080-1089.
[9] Ruhullah M, Singh HR, Shah S, et al. Primary hip spica with crossed retrograde intramedullary rush pins for the management of diaphyseal femur fractures in children: A prospective, randomized study. Niger Med J. 2014;55(2): 111-115.
[10] Tung T, Tufescu T. The cortical step sign fails to prevent malrotation of a nailed femoral shaft fracture: a case report. Case Rep Orthop. 2014;2014:301723.
[11] Kubiak EN, Beebe MJ, North K, et al. Early weight bearing after lower extremity fractures in adults. J Am Acad Orthop Surg. 2013;21(12):727-738.
[12] Meena S, Trikha V, Singh V, et al. Uncoiling of reamer during intramedullary nailing for fracture shaft of femur. J Nat Sci Biol Med. 2013;4(2):481-484.
[13] Levy JA, Podeszwa DA, Lebus G, et al. Acute complications associated with removal of flexible intramedullary femoral rods placed for pediatric femoral shaft fractures. J Pediatr Orthop. 2013;33(1):43-47.
[14] Giessauf C, Glehr M, Bernhardt GA, et al. Quality of life after pertrochanteric femoral fractures treated with a γ nail: a single center study of 62 patients. BMC Musculoskelet Disord. 2012; 13:214.
[15] Neubauer T, Krawany M, Leitner L, et al. Retrograde femoral nailing in elderly patients: outcome and functional results. Orthopedics. 2012;35(6):e855-861.
[16] Gordon JE, O'Donnell JC. Tibia fractures: what should be fixed? J Pediatr Orthop. 2012;32 Suppl 1:S52-61.
[17] Chan PK, Chan KB, Lui TH, et al. Breakage of the radiopaque wire from the medullary tube during closed antegrade intramedullary nailing for femoral shaft fracture. J Orthop Surg (Hong Kong). 2012;20(1):118-120.
[18] Faucett SC, Collinge CA, Koval KJ. Is reconstruction nailing of all femoral shaft fractures cost effective? A decision analysis. J Orthop Trauma. 2012;26(11):624-632.
[19] Halvorson JJ, Barnett M, Jackson B, et al. Risk of septic knee following retrograde intramedullary nailing of open and closed femur fractures. J Orthop Surg Res. 2012;7:7.
[20] Hawi N, Haentjes J, Suero EM, et al. Navigated femoral shaft fracture treatment: current status. Technol Health Care. 2012; 20(1):65-71.
[21] Liodakis E, Kenawey M, Petri M, et al. Factors influencing neck anteversion during femoral nailing: a retrospective analysis of 220 torsion-difference CTs. Injury. 2011; 42(11): 1342-1345.
[22] Köseolu E, Durak K, Bilgen MS, et al. Comparison of two biological internal fixation techniques in the treatment of adult femur shaft fractures (plate-screws and locked intramedullary nail). Ulus Travma Acil Cerrahi Derg. 2011;17(2):159-165.
[23] Wang G, Pan T, Peng X, et al. A new intramedullary nailing device for the treatment of femoral shaft fractures: a biomechanical study. Clin Biomech (Bristol, Avon). 2008; 23(3):305-312.
[24] 潘滔,王国栋,王军,等.髓内持骨动力性髓内钉的研制及临床初步应用[J].中国修复重建外科杂志,2007,21(12):1361-1365.
[25] Herrera A, Ibarz E, Cegoñino J, et al. Applications of finite element simulation in orthopedic and trauma surgery. World J Orthop. 2012;3(4):25-41
[26] Liu XS, Wang J, Zhou B, et al. Fast trabecular bone strength predictions of HR-pQCT and individual trabeculae segmentation-based plate and rod finite element model discriminate postmenopausal vertebral fractures. J Bone Miner Res. 2013;28(7):1666-1678.
[27] Varga P, Schefzig P, Unger E, et al. Finite element based estimation of contact areas and pressures of the human scaphoid in various functional positions of the hand. J Biomech. 2013;46(5):984-990.
[28] Nishiyama KK, Macdonald HM, Hanley DA, et al. Women with previous fragility fractures can be classified based on bone microarchitecture and finite element analysis measured with HR-pQCT. Osteoporos Int. 2013;24(5):1733-1740.
[29] Meng L, Zhang Y, Lu Y. Three-dimensional finite element analysis of mini-external fixation and Kirschner wire internal fixation in Bennett fracture treatment. Orthop Traumatol Surg Res. 2013;99(1):21-29.
[30] Kantardzi I, Vasiljevi D, Blazi L, et al. Influence of cavity design preparation on stress values in maxillary premolar: a finite element analysis. Croat Med J. 2012;53(6):568-576.
[31] Jia YW, Cheng LM, Yu GR, et al. A finite element analysis of the pelvic reconstruction using fibular transplantation fixed with four different rod-screw systems after type I resection. Chin Med J (Engl). 2008;121(4):321-326.
[32] Graeff C, Marin F, Petto H, et al. High resolution quantitative computed tomography-based assessment of trabecular microstructure and strength estimates by finite-element analysis of the spine, but not DXA, reflects vertebral fracture status in men with glucocorticoid-induced osteoporosis. Bone. 2013;52(2):568-577.
[33] Wang X, Sanyal A, Cawthon PM, et al. Prediction of new clinical vertebral fractures in elderly men using finite element analysis of CT scans. J Bone Miner Res. 2012;27(4):808-816.
[34] 丁悦,刘尚礼,马若凡,等.国人股骨假体设计的解剖学基础[J].中国临床解剖学杂志,2003,21(4):341-343.
[35] 姜海波,葛世荣.基于CT扫描人体股骨的有限元分析[J].工程力学,2007,24(10):156-159.
[36] Duda GN, Heller M, Albinger J, et al. Influence of muscle forces on femoral strain distribution. J Biomech. 1998;31(9): 841-846.
[37] Ricci WM, Gallagher B, Brandt A, et al. Is after-hours orthopaedic surgery associated with adverse outcomes? A prospective comparative study. J Bone Joint Surg Am. 2009; 91(9):2067-2072.
[38] Napoli N, Novack D, Armamento-Villareal R. Bisphosphonate-associated femoral fracture: implications for management in patients with malignancies. Osteoporos Int. 2010;21(4):705-708.
[39] Kuyucu E, Koçyi?it F, Ciftçi L. The importance of patient compliance in nonunion of forearm fracture. Int J Surg Case Rep. 2014;5(9):598-600.
[40] Schneider E, Michel MC, Genge M, et al. Loads acting in an intramedullary nail during fracture healing in the human femur. J Biomech. 2001;34(7):849-857.
[41] Sathyendra V, Donahue HJ, Vrana KE, et al. Single Nucleotide Polymorphisms in Osteogenic Genes in Atrophic Delayed Fracture-Healing: A Preliminary Investigation. J Bone Joint Surg Am. 2014;96(15):1242-1248.
[42] Illukka E, Boudrieau RJ. Surgical repair of a severely comminuted maxillary fracture in a dog with the a titanium locking plate system. Vet Comp Orthop Traumatol. 2014. in press.
[43] Knothe U, Knothe Tate ML, Klaue K, et al. Development and testing of a new self-locking intramedullary nail system: testing of handling aspects and mechanical properties. Injury. 2000;31(8):617-626.
[44] Klein P, Schell H, Streitparth F, et al. The initial phase of fracture healing is specifically sensitive to mechanical conditions. J Orthop Res. 2003;21(4):662-669.
[45] Aaron RK, Ciombor DM, Keeping H, et al. Power frequency fields promote cell differentiation coincident with an increase in transforming growth factor-beta(1) expression. Bioelectromagnetics. 1999;20(7):453-458.
[46] Sahu RL, Sikdar J. Fracture union in closed interlocking nail in femoral fracture. JNMA J Nepal Med Assoc. 2010;49(179): 228-231.