Strategies in Trauma and Limb Reconstruction

Register      Login

VOLUME 13 , ISSUE 2 ( August, 2018 ) > List of Articles

Original Article

Measurement of wire deflection on loading may indicate union in Ilizarov constructs, an in vitro model

Beth Lineham, Todd Stewart

Keywords : Ilizarov, Frame, Wire deflection, Biomechanics

Citation Information : Lineham B, Stewart T. Measurement of wire deflection on loading may indicate union in Ilizarov constructs, an in vitro model. 2018; 13 (2):75-80.

DOI: 10.1007/s11751-018-0306-1

License: CC BY-NC-SA 4.0

Published Online: 01-06-2016

Copyright Statement:  Copyright © 2018; The Author(s).


No entirely reliable method exists for assessing union during Ilizarov treatment. Premature removal results in potential treatment failure; hence, alternative methods warrant investigation. Wire deflection might provide an indication of fracture site deformation on weight bearing, indicating progress towards union. This study aimed to test a method for assessing wire deflection within an Ilizarov frame. (1) To assess the repeatability of our novel measurement method in measuring wire deflection within an Ilizarov frame in vitro. (2) To compare the amount of wire deflection in an unstable model with that in an intact bone model. (3) To assess accuracy of this method by comparing wire deflection measured with overall machine extension. Tests were performed on clinical grade-tensioned fine wire 4-ring Ilizarov constructs stabilising a simulated fracture, with and without an unstable defect. Models were sequentially loaded to 700 N using an Instron testing machine. A digital depth gauge attached to the superior ring measured relative wire displacement at the ring closest to the fracture. Tests were repeated 3 times. (1) Both unstable and stable bone models produced highly repeatable load deformation curves (R2 = 0.98 and 0.99). (2) In the unstable model, wires tensioned at 882 and 1274 N produced mean maximum deflections of 2.41 and 2.69 mm compared with 0.05 and 0.04 mm in the intact bone model (significant p < 0.0001). (3) Wire deflection and machine extension results were strongly correlated (r = 0.99). A measurable difference in wire deflection between stable and unstable situations exists using this method which appears accurate and repeatable, with clear correlation between displacement and load and displacement and machine extension. This approach might be clinically applicable, and further clinical testing is required.

PDF Share
  1. Babatunde OM, Fragomen AT, Rozbruch SR (2010) Noninvasive quantitative assessment of bone healing after distraction osteogenesis. HSS J 6(1):71-78
  2. Corrales LA, Morshed S, Bhandari M, Miclau T III (2008) Variability in the assessment of fracture-healing in orthopaedic trauma studies. J Bone Joint Surg Am Vol 90A(9):1862-1868
  3. Richardson J, J H. The measurement of fracture healing. In: De Bastiani G, Apley A, Goldberg A (eds) Orthofix external fixation in trauma and orthopaedics, 1 edn. Springer, London, p 32-44
  4. Watson MA, Mathias KJ, Maffulli N (2000) External ring fixators: an overview. Proc Inst Mech Eng Part H J Eng Med 214(H5):459-470
  5. Lie CW (2009) W C. Limb lengthening in short-stature patients using monolateral and circular external fixators. Hong Kong Med J 15:280-284
  6. Adair A, Narayan B, Andrews C, Laverick M, Marsh D (2003) The complication rate in Ilizarov surgery. Orthop Proc 85-B(SUPP II):139
  7. Paley D, Herzenberg JE, Paremain G, Bhave A (1997) Femoral lengthening over an intramedullary nail. A matched-case comparison with Ilizarov femoral lengthening. J Bone Joint Surg Am 79(10):1464-1480
  8. Britten S, Hepworth A, Hasson M, Sian PS (2008) Avoiding premature frame removal in tibial fractures. Orthop Proc 90-B(SUPP III):569
  9. Siffert RS, Kaufman JJ (1996) Acoustic assessment of fracture healing. Capabilities and limitations of “a lost art”. Am J Orthop (Belle Mead, NJ) 25(9):614-618
  10. Lowet G, Vander Perre G (1996) Ultrasound velocity measurement in long bones: measurement method and simulation of ultrasound wave propagation. J Biomech 29(10):1255-1262
  11. Eyres KS, Bell MJ, Kanis JA (1993) Methods of assessing new bone formation during limb lengthening. Ultrasonography, dual energy X-ray absorptiometry and radiography compared. Bone Joint J 75-B(3):358-64
  12. Bail HJ, Kolbeck S, Krummrey G et al (2002) Ultrasound can predict regenerate stiffness in distraction osteogenesis. Clin Orthop Relat Res 404:362-367
  13. Markel MD, Chao EY (1993) Noninvasive monitoring techniques for quantitative description of callus mineral content and mechanical properties. Clin Orthop Relat Res 293:37-45
  14. Richards J (1987) Stiffness in healing fractures. CRC Crit Rev Biomed Eng 15(2):145-185
  15. Cunningham JL, Kenwright J, Kershaw CJ (1990) Biomechanical measurement of fracture-healing. J Med Eng Technol 14(3):92-101
  16. Kristiansen B, Borgwardt A (1992) Fracture-healing monitored with strain-gauges-external fixation of 7 humeral neck fractures. Acta Orthop Scand 63(6):612-614
  17. Bedzinski R, Tyndyk M (2000) Experimental methods of stress and strain analysis in orthopaedics biomechanics. Acta Bioeng Biomech 2(2):3-23
  18. Kummer FJ (1989) Biomechanics of the Ilizarov external fixator. Bull Hosp Joint Dis Orthop Inst 49(2):140-147
  19. Gessmann J, Baecker H, Jettkant B, Muhr G (2011) Seybold D (2011) Direct and indirect loading of the Ilizarov external fixator: the effect on the interfragmentary movements and compressive loads. Strategies Trauma Limb Reconstr 6(1):27-31
  20. La Russa V, Skallerud B, Klaksvik J, Foss OA (2011) Reduction in wire tension caused by dynamic loading. An experimental Ilizarov frame study. J Biomech 44(8):1454-1458
  21. Hessmann M, Nork S, Sommer C, Twaddle B, AO Foundation (2008) Distal tibia 43-A2 CREF. Available at: Accessed 11 Dec 2017
  22. Aquarius R, Van Kampen A, Verdonschot N (2007) Rapid pretension loss in the Ilizarov external fixator: an in vitro study. Acta Orthop 78(5):654-660
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.