Strategies in Trauma and Limb Reconstruction

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VOLUME 16 , ISSUE 3 ( September-December, 2021 ) > List of Articles

ORIGINAL RESEARCH

Measurement of Wire Deflection on Loading may Indicate Union in Ilizarov Constructs: A Pilot Study

Todd Stewart, John Ward

Citation Information : Stewart T, Ward J. Measurement of Wire Deflection on Loading may Indicate Union in Ilizarov Constructs: A Pilot Study. 2021; 16 (3):132-137.

DOI: 10.5005/jp-journals-10080-1537

License: CC BY-NC-SA 4.0

Published Online: 15-01-2022

Copyright Statement:  Copyright © 2021; The Author(s).


Abstract

Introduction: No entirely reliable method to assess union during Ilizarov treatment exists. Premature frame removal results in treatment failure, and alternative methods of assessment warrant investigation. Wire deflection might provide an indication of fracture site deformation on weight-bearing, indicating progress towards union. A previous in vitro study from our group demonstrated this approach may be clinically applicable. We investigated translation of this method into clinical practice in an observational pilot study. Materials and methods: Patients with tibial shaft fractures treated with Ilizarov frames were recruited. A prototype depth gauge was used to measure wire deflection on weight-bearing. Investigators undertaking the measurement were blinded to the clinical stage of treatment, and clinicians caring for the patient were blinded to deflection results. Patient records were reviewed at the end of treatment to determine likely fracture stability at each time point. Deflection per kg of weight applied, per mm from the ring was compared between stable and unstable situations. Results: Thirty-one measurements were obtained in 14 patients. The situation was deemed stable at 13 and unstable at 18 measurements. The median deflection in the stable group was 0.030 microns/kg/mm (IQR 0.005–0.104) and 0.165 microns/kg/mm (IQR 0.072–0.328) in the unstable group. This difference was statistically significant (Wilcoxon Mann–Whitney test p = 0.0014). ROC curve analysis revealed that wire deflection was able to predict clinical stability (AUC 0.84, p <0.0001). Various technical problems were encountered when using the device which would potentially limit its clinical utility in its current form. Conclusion: In this set of observations, wire deflection was significantly associated with clinically and radiologically determined stability. Though various practical limitations were encountered in using the prototype measurement device, this proof-of-concept study supports further development of this approach. The research group plan to develop a smaller, more reliable device for further clinical testing in a larger group of patients.


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  1. Babatunde OM, Fragomen A, Rozbruch R. Noninvasive quantitative assessment of bone healing after distraction osteogenesis. HSS J 2007;6(1):71–78. DOI: 10.1007/s11420-009-9130-y.
  2. Corrales LA, Morshed S, Bhandari M, et al. Variability in the assessment of fracture-healing in orthopaedic trauma studies. J Bone Joint Surg Am 2008;90A(9):1862–1868. DOI: 10.2106/JBJS.G.01580.
  3. Richardson J.B., Hardy J.R.W. (2000) The Measurement of Fracture Healing. In: De Bastiani G., Apley A.G., Goldberg A. (eds) Orthofix External Fixation in Trauma and Orthopaedics. Springer, London. DOI: 10.1007/978-1-4471-0691-3_5.
  4. Watson MA, Mathias KJ, Maffulli N. External ring fixators: an overview. Proc Inst Mech Eng H 2000;214(5):459–470. DOI: 10.1243/0954411001535480.
  5. Bail HJ, Kolbeck S, Krummrey G, et al. Ultrasound can predict regenerate stiffness in distraction osteogenesis. Clin Orthop Relat Res 2002;(404):362–367. DOI: 10.1097/00003086-200211000-00053.
  6. Eyres KS, Bell MJ, Kanis JA. Methods of assessing new bone formation during limb lengthening. Ultrasonography, dual energy X-ray absorptiometry and radiography compared. J Bone Joint Br 1993; 75-B(3):358–364. DOI: 10.1302/0301-620X.75B3.8496200.
  7. Markel M, Chao E. Noninvasive monitoring techniques for quantitative description of callus mineral content and mechanical properties. Clin Orthop Relat Res 1993;(293):37–45. PMID: 8339505.
  8. Cunningham JL, Kenwright J, Kershaw CJ. Biomechanical measurement of fracture healing. J Med Eng Technol 1990;14(3): 92–101. DOI: 10.3109/03091909009015420.
  9. Richards J. Stiffness in healing fractures. Crit Rev Biomed Eng 1987;15(2):145–185. PMID: 3319415.
  10. Gessmann J, Baecker H, Jettkant B, et al. Direct and indirect loading of the Ilizarov external fixator: the effect on the interfragmentary movements and compressive loads. Strategies Trauma Limb Reconstr 2011;6(1):27–31. DOI: 10.1007/s11751-011-0103-6.
  11. Lineham B, Stewart T, Harwood P. Measurement of wire deflection on loading may indicate union in Ilizarov constructs, an in vitro model. Strategies Trauma Limb Reconstr 2018;13(2):75–80. DOI: 10.1007/s11751-018-0306-1.
  12. Kristiansen B, Borgwardt A. Fracture healing monitored with strain-gauges–external fixation of 7 humeral neck fractures. Acta Orthop Scand 1992;63(6):612–614. DOI: 10.1080/17453679209169719.
  13. Aquarius R, Van Kampen A, Verdonschot N. Rapid pre-tension loss in the Ilizarov external fixator: an in vitro study. Acta Orthop 2007;78(5):654–660. DOI: 10.1080/17453670710014356.
  14. Gessmann J, Jettkant B, Königshausen M, et al. Improved wire stiffness with modified connection bolts in Ilizarov external frames: a biomechanical study. Acta Bioeng Biomech 2012;14(4):15–21. PMID: 23394181.
  15. La Russa V, Skallerud B, Klaksvik J, et al. Reduction in wire tension caused by dynamic loading. An experimental Ilizarov frame study. J Biomech 2011;44(8):1454–1458. DOI: 10.1016/j.jbiomech.2011.03.018.
  16. Claes LE, Cunningham JL. Monitoring the mechanical properties of healing bone. Clin Orthop Relat Res 2009;467(8):1964–1971. DOI: 10.1007/s11999-009-0752-7.
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