Abstract
Purpose
We designed a sensor that measures the bending moments at the articulations and the torque of the rod of a Hoffmann II® external fixation. We considered the effect of the callus formation in the stabilisation of a “fracture-fixation system.”
Methods
Four Hoffmann II® frame configurations were mechanically tested. Two carbon fibre tubes represent the bone fragments (length 180 mm, outer diameter 25 mm, inner diameter 19 mm). The callus is represented by the interposition of springs of different rigidity (10–405 N/mm) in the fracture gap between the tubes.
Results
The deformation of the frame is in inverse proportion to the stiffness of the callus; the slope of the curve drops rapidly during early development of the callus, to reach a plateau after some 50 % of recovery of the normal mechanical characteristics of the bone. This simulation supports the theoretical approach, i.e. the external frame resists larger stresses at the start of the fracture healing. Over a callus stiffness of some 200 N/mm the pattern of the curves remains similar, regardless of the frame configuration.
Conclusion
An optimisation of the frame is possible, adapted to the actual mechanical situation of the callus. A monitoring system is deemed reliable after making sure that the elementary components behave the same way in the clinical condition as in the laboratory. In an experimental set up we confirmed its reliability in a clinical-like situation.
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References
Beaupré GS, Hayes WC, Jofe MH, White WW (1983) Monitoring fracture site properties with external fixation. J Biomech Eng 105:120–126
Bourgois R, Burny F (1972) Measurement of the stiffness of fracture callus in vivo. A theoretical study. J Biomech 5:85–91
Briggs BT, Chao EYS (1982) The mechanical performance of the standard Hoffmann-Vidal external fixation apparatus. J Bone Joint Surg 64A:566–573
Burny F (1968) Etude par jauges de déformation de la consolidation des fractures en clinique. Acta Orthop Belg 34:917–927
Burny F (1976) Biomécanique de la consolidation des fractures. Mesure de la rigidité du cal in vivo. Etude théorique, expérimentale et clinique. Application à la théorie de l’ostéosynthèse, Ph.D. Thesis, Université Libre de Bruxelles, pp 197
Burny F, Bourgois R (1965) Etude théorique de l’ostéotaxis. In: Van Geertruyden J, de Marneffe R (eds) Fixation externe en chirurgie. Imprimerie Médicale et Scientifique, Bruxelles, pp 109–119
Burny F, Donkerwolcke M, Bourgois R, Domb M, Saric O (1984) Twenty years experience in fracture healing measurement with strain gauges. Orthopedics 7:1823–1826
Claes L, Grass R, Schmickal T, Kisse B, Eggers C, Gerngroß H, Mutschler W, Arand M, Wintermeyer T, Wentzensen A (2002) Monitoring and healing analysis of 100 tibial shaft fractures. Langenbeck’s Arch Surg 387:146–152
Claes L, Cunningham JL (2009) Monitoring the mechanical properties of healing bone. Clin Orthop Relat Res 467:1964–1971
Cunningham JL, Evans M, Harris JD, Kenwright J (1987) The measurement of stiffness of fractures treated with external fixation. Eng Med 16:229–232
Hente R, Cordey J, Perren S (2003) In vivo measurement of bending stiffness in fracture healing. BioMedl Eng Online 2(8):1–16. http://www.biomedical-engineering-online.com/content/2/1/8. Accessed July 2012
Jenkins P, Nokes L (1994) The use of strain gauges to measure bone fracture healing. A review. Current Orthop 8:116–118
Juan JA, Prat J, Vera P, Hoyos JV, Sanchez-Lacuesta J, Peris JL, Dejaz R, Alepuz RR (1992) Biomechanical consequences of callus development in Hoffmann, Wagner, Orthofix and Ilizarov external fixators. J Biomech 25:995–1006
Kaplan SJ, Hayes WC, Mudan P, Lelli JL, White AA (1985) Monitoring the healing of a tibial osteotomy in the rabbit treated with external fixation. J Orthop Res 3:325–330
Kristiansen B, Borgwardt A (1992) Fracture healing monitoring with strain gauges. Acta Orthop Scand 63:612–614
Lortat-Jacob A, Lelong P, Benoit J, Ramadier JO (1982) Stabilité expérimentale du fixateur externe de Hoffmann: présentation d’un nouveau matériel. Rev Chir Orthop 68:83–90
Nishimura N (1984) Serial strain gauge measurement of bone healing in Hoffmann external fixation. Nippon Seikeigeka Gakkai Zasshi 58:23–40
Prat J (1990) Análisis del proceso de reparación ósea mediante sistemas de fijación externa. Thesis, Alcalà de Henares, Spain, 1990
Prat J, Juan JA, Vera P, Hoyos JV, Dejoz R, Peris JL, Sanchez-Lacueste S, Comìn M (1994) Load transmission through the callus site with external fixation systems: theoretical and experimental analysis. J Biomech 27:469–478
Ricciardi L, Perissinotto A, Dabala M (1992) External callus development on ultrasound and its mechanical correlation. Ital J Orthop Trauma 18:223–229
Seide K, Weinrich N, Wenzl ME, Wolter D, Jürgens C (2004) Three-dimensional load measurements in an external fixator. J Biomech 37:1361–1369
Vera P, Hoyos JV, Nieto J (1981) Concepción de un fijador externo capaz de controlar el stado tensional al nivel de la fractura. IV Simposium de Biomecánica, Valencia
Conflict of interest
The sensor was manufactured by Stryker, following the instructions of the first author. The experiments were conducted using the RD facilities of Stryker, supervised by the first author.
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Burny, F., Burny, W., Donkerwolcke, M. et al. Effect of callus development on the deformation of external fixation frames. International Orthopaedics (SICOT) 36, 2577–2580 (2012). https://doi.org/10.1007/s00264-012-1676-5
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DOI: https://doi.org/10.1007/s00264-012-1676-5