The impact of the type of derotation mechanism on the stiffness of the Ilizarov fixator

• Autorzy: Morasiewicz P. , Filipiak J. , Konietzko M. , Dragan Sz.
• Języki publikacji: EN

Abstrakty

EN

One of the applications of the Ilizarov apparatus is the correction of rotational deformities. There are several types of designs commonly used for derotation. Different types of derotators have different mechanical properties, which affect the stability of the entire Ilizarov apparatus. The aim of this study was to determine the stiffness of the Ilizarov fixator depending on the type of derotation mechanism. We analyse three types of derotators: the type Z, the type H, and the cubicoid derotator. The tests were conducted on physical models in which the fixator analysed was fitted to polyethylene pipe segments. The reference fixator was the Ilizarov apparatus in the configuration adapted for thigh lengthening. The pipe segments intersected at a point corresponding to the osteotomy site of the distal thigh. The fixator was assembled with one proximal arch fixed with two Schanz screws, a proximal ring fixed with two Kirschner wires (K-wires), a middle free ring, and a distal ring fixed with three K-wires. There were three different types of derotation mechanisms installed between the proximal and middle rings. We determined the axial stiffness kA and the transverse stiffnesses of the compared fixators in two planes: frontal kM-L and sagittal kA-P. The results of the research lead to two basic conclusions. Firstly, the use of any of the derotators analysed has no negative impact on the stiffness of the Ilizarov apparatus. Secondly, similar stiffness values of the fixators with different derotation mechanisms suggest their equal applicability and the choice between them can be made based on practical considerations. In the case of axial stiffness, the differences do not exceed 7.5%. The highest value of stiffness kA was obtained for the type H derotator, while the lowest value was obtained for the type Z derotator. There is a greater difference in the case of transverse stiffness in the sagittal plane, which only concerns the fixator with the type Z derotators. The stiffness coefficient kA-P for that fixator is lower by approximately 19% compared to the reference fixator.

Słowa kluczowe

EN

Ilizarov external fixator; bone fragments derotation; bone elongation; fixator stiffness

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Acta of Bioengineering and Biomechanics
• Rocznik: 2012
• Tom: Vol. 14, no. 1
• Strony: 67--73
• Opis fizyczny: Bibliogr. 20 poz., rys.

Twórcy

autor

Morasiewicz P.

autor

Filipiak J.

autor

Konietzko M.

autor

Dragan Sz.

• Department and Clinic of Orthopaedic and Traumatologic Surgery, Wrocław Medical University,

Bibliografia

• [1] ARO H.T., WAHNER H.T., CHAO E.Y., Healing patterns of transverse and oblique osteotomies in the canine tibia under external fixation, Journal Orthopaedics Trauma, 1991, 5, 351–364.
• [2] AUGAT P., BURGER J., SCHORLEMMER S., HENKE T., PERAUS M., CLAES L., Shear movenent at the fracture site delays healing in a diaphyseal fracture model, Journal of Orthopaedic Research, 2003, 21, 1011–1017.
• [3] BARAN O., HAVITCIOGLU H. et al., The stiffness characteristics of hybryd Ilizarov fixator, J. Biomech., 2008, 41, 2960–2963.
• [4] CATAGNI M. et al., Cosmetic bilateral leg lengthening, J. Bone Joint Surg. Br., 2005, 87, 1402–1405.
• [5] CHOI I. et al., Correction of the genu recurvatum by the Ilizarov method, J. Bone Joint Surg. Br., 1999, 81, 769–774.
• [6] FILIPIAK J., MORASIEWICZ L., Assessment of the effect of hybrid implant systems in the Ilizarov fixator on stability of fragments of the femur subjected elongation, Acta Bioeng. Biomech., 2001, 3, 15–24.
• [7] FILIPIAK J., KRAWCZYK A., MORASIEWICZ L., Distribution of radiological density in bone regenerate in relation to cyclic displacements of bone fragments, Acta Bioeng. Biomech., 2009, 3, 3–9.
• [8] GROSS R., Leg lengthening, Lancet, 1999, 354, 1574–1575.
• [9] GRUBOR P., GRUBOR M., ASOTIC M., Comparision of stability of different types of external fixation, Med. Arhc., 2011, 65, 157–159.
• [10] ILIZAROW G.A., The tension–stress effect on the genesis and growth of tissues. Part I. The influence of stability of fixation and soft-tissue preservation, Clin. Orthop. Relat. Res., 1989, 238, 249–281.
• [11] KĄCKI W., TĘSIOROWSKI M., ZARZYCKA M. et al., Wydłużanie podudzia metodą Ilizarowa, Chir. Narządów Ruchu. Ortop. Pol., 1994, Supl. 1, 111–114.
• [12] La RUSSA V., SKALLERUD B. et al., Reduction in wire tension caused by dynamic loading. An experimental Ilizarov frame study, J. Biomech., 2011, 44, 1454–1458.
• [13] MANNER H.R., HUEBL M., RADLER C. et al., Accuracy of complex lower-limb deformity correction with external fixation: a comparison of the Taylor Spatial Frame with the Ilizarov Ringfixator, J. Child. Orthop., 2007, 1, 55–61
• [14] MOENS P., LAMMENS J., MOLENAERS G. et al., Femoral derotation for increased hip anteversion, J. Bone Joint Surg. Br., 1995, 77, 107–109.
• [15] MYLLE J., LAMMENS J., FARBY G., Derotation osteotomy to correct rotational deformities of the lower extremities in children. A comparison of three methods, Acta Orthop. Belg., 1993, 59, 287–292.
• [16] PALEY D., TETSWORTH K., Operative Orthopaedics; Charter 61: Deformity Correction by the Ilizarov Technique, 1993, 937–948.
• [17] SCHELL H., EPARI D.R., KASSI J.P., BRAGULLA H., BAIL H.J., DUDA G.N., The course of bone healing is influenced by the initial shear fixation stability, Journal of Orthopeadic Research, 2005, 23, 1022–1028.
• [18] SYNDER M., NIEDZIELSKI K., FABIŚ J., Zastosowanie aparatu Ilizarowa do wydłużania kończyn dolnych, Chir. Narz. Ruchu Ortop. Pol., 1994, Supl. 1, 125–128.
• [19] THEIS J.C., SIMPSON H., KENWRIGHT J., Correction of complex lower limb deformities by the Ilizarov technique: An audit of complications, J. Orthop. Surg., 2000, 8, 67–71.
• [20] YILMAZ E., BELHAN O., KARAKURT L., ARSLAN N., SERIN E., Mechanical performance of hybrid Ilizarov external fixator in comparison with Ilizarov circular external fixator, Clinical Biomechanics., 2003, 18, 518–522.