Load transmission through the callus site with external fixation systems: theoretical and experimental analysis
| Autor: | R. Dejoz, Jaime Prat, J.A. Juan, J.L. Peris, P. Vera, M. Comín, J.V. Hoyos, J. Sánchez-Lacuesta |
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| Rok vydání: | 1994 |
| Předmět: |
Materials science
External Fixators medicine.medical_treatment Biomedical Engineering Biophysics Dynamization Bone healing Models Biological Fixation (surgical) External fixation Fracture Fixation Tensile Strength medicine Animals Orthopedics and Sports Medicine Bony Callus Elastic modulus Orthodontics Fracture Healing Tibia Rehabilitation Biomechanics Reproducibility of Results Anatomy Equipment Design Elasticity Tibial Fractures Callus Fracture (geology) Female Rabbits Stress Mechanical |
| Zdroj: | Journal of biomechanics. 27(4) |
| ISSN: | 0021-9290 |
| Popis: | The fracture callus contribution to the total rigidity of external fixator-fractured bone element was analysed. This study was achieved from both theoretical and experimental perspectives. The theoretical study was done using the finite element method with a three-dimensional model. In this model, both the callus and the development of its elastic characteristics were considered. A series of 38 New Zealand-California white rabbits with tibial fractures treated with some external fixation system was used in this study. Such devices could reproduce either rigid or elastic features. The frame dynamization can be obtained at different fracture healing stages. Animals were classified into four series: (1) rigid fixators, (2) dynamized fixators two weeks after surgery, (3) three weeks after surgery and (4) four weeks after surgery. Tension tests were performed to evaluate callus strength. Theoretical results showed significant levels of callus load transmission (85.5%) when the callus elastic modulus is 1 100 of the elastic modulus of intact bone in an external fixator with rigid features. Experimental analysis of the callus obtained with different external fixator systems did not show differences among them. This fact implies that the immature callus theoretically modelled ( E = 100 N mm −2 ) appears early in the rabbit fracture model (before two weeks, when first dynamisation was made), for this reason no differences were found between the two types of treatment (rigid and dynamized systems). This fact questions the reliability of the dynamization process in external fixation of fractures and it implies accurate investigations in the clinical field. |
| Databáze: | OpenAIRE |
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