Εμβιομηχανική του μηριαίου οστού κονίκλου: Τρισδιάστατη ανακατασκευή του μηριαίου οστού και συγκριτική αξιολόγηση των πειραματικών διατάξεων κάμψεως.

Abstract

Η παρούσα εργασία εξετάζει την αποτελεσματικότητα τόσο των καινοτόμων όσο και των παραδοσιακών πειραματικών τεχνικών στον τομέα της εμβιομηχανικής των οστών, με την κατασκευή των αντίστοιχων υπολογιστικών μοντέλων. Θα χρησιμοποιηθούν υπολογιστικές μέθοδοι για τη σύγκριση και την αξιολόγηση διαφορετικών πειραματικών τεχνικών, που αποσκοπούν στον προσδιορισμό των μηχανικών ιδιοτήτων των οστών, με βασικό στόχο την ανάδειξη των προτερημάτων και των αδυναμιών της εκάστοτε τεχνικής.

The current thesis studies the effectiveness of innovative but also traditional experimental techniques in the field of bone biomechanics, through the construction of computational models. Computational methods will be used for the comparison and the evaluation of different experimental methods, which are used for the determination of bone mechanical properties, in order to illustrate the benefits and the diffculties of each method. The science of biomechanics is becoming more and more part of the clinical practice, especially in the field of orthopaedics. The introduction of modern techniques, contributes to the improvement of the diagnostic methods as well as of the therapeutic procedure, in order to eliminate the postoperative complications and the possibility of a failure of the clinical treatment. The development of more effective and radical treatment techniques leads to the decrease of the recovery time, when the patience should stay immobilized, with multiple benefits. However, the major problem of the above convenient approach, is the imposed restrictions of experimental biomechanical techniques, which render the application of those techniques in clinical practice unattainable. Those restrictions concern, first of all, the weakness of utilizing the appropriate specimen, for example human bones, in order to export results corresponding to reality rather than to insufficient approaches. The major problem of experimental methods is introduced by the inability of their direct application in patients during the clinical procedure, due to the destruction of experimental specimen and the lack of reproducibility of the procedure. The computational methods attempt to solve the above weaknesses of the experimental biomechanical methods, by substituting the parts of the procedure, which cannot be transferred in the clinical practice. The computational simulations use the information of the experimental data, in order to extract important results concerning the bone's mechanical properties and their response to certain loadings. Those results would require the application of biomechanical techniques in patients in order to be collected experimentally. In the current thesis, a femur rabbit bone is tested under different loading procedures. The first step of the procedure, contains the use of computed tomography in order to receive accurate data for the bone geometry. Those information will be used for the construction of the three dimensional model of the femur bone. The computational model will be compared with experimental data for the confirmation of its accuracy. In the next step, the created model will be subjected in computational tests that simulate the experimental procedure. The study contains three and four point bending tests applied in both free and embedded bone specimen. The computational results will be compared with respective experimental results and will be used for the evaluation of each experimental technique. The purpose of the study is to illustrate the advantages of each test in different cases, in order to contribute to the optimization of the experimental techniques for the optimum use of the resources.