This paper provides an analysis from a biomechanical perspective of the medial opening wedge high tibial osteotomy surgery, a medical procedure commonly used in treating knee osteoarthritis. The aim of this research is to improve the analysed surgical strategy by establishing optimal values for several very important parameters for the geometric planning of this type of surgical intervention. The research methods used are numerical and experimental. We used finite element, a numerical method used to study the intraoperative behavior of the CORA area for different positions of the initiation point of the cut of the osteotomy plane and for different correction angles. We also used an experimental method in order to determine the maximum force which causes the occurrence of cracks or microcracks in the CORA area. This helped us to determine the stresses, the maximum forces, and the force-displacement variations in the hinge area, elements that allowed us to identify the optimal geometric parameters for planning the surgery.

Background and objectives: Osteoporotic spine fractures represent a significant factor for decreasing quality of life in the elderly female population. Understanding the mechanisms involved in producing these fractures can improve their prevention and treatment. This study presents a biomechanical method to produce a vertebral fracture, conducted on a human spine segment, observing the displacements and strains in the intervertebral disc, endplate, and vertebral body. Materials and Methods: We performed two tests, one corresponding to an extension loading, and the second to an axial loading. Results: The maximum displacement in the target vertebral body presented higher values in the case of the extension as compared to the axial strain where it mainly occurred after the fracture was produced. The strains occurred simultaneously on both discs. In the case of the axial strain, due to the occurrence of the fracture, the maximum value was recorded in the spine body, while in the case of the extensions, it occurred in the neural part of the upper disc. The advantage of this method was that the entire study was an experiment, using optical methods, increasing the precision of the material data input. Conclusions: The research method allowed recording in real time of a larger amount of data from the different components of the spine segment. If there was an extension component of the compression force at the moment of the initial loading, part of this load was absorbed by the posterior column with higher mechanical resistance. After the maximum capacity of the absorption was reached, in both situations the behavior was similar.

The presented article is an original contribution which implies the design of a specialized device for high tybial osteotomy (HTO) optimization. In the papers are presented the sources that imply HTO, the axial deviations of the human lower member from the correct position. This sources are the gonarthosys owed to the usage of the knees cartilages or owed to some diseases (such as the Blount disease) and the vicious consolidated fractures. After presenting the needs to realize such a specialized device for HTO, the principal requests the device shall fulfill are underlined. Starting from these , two sub ensembles were projected, one for the tibial positioning and for the execution of the hole from the center of rotation of angulation (CORA), and the second one for the realization of the cuts. Both sub ensembles have been 3D modeled in Catia V5R20. The model was designed mounted on the bone.

Given the complex form of the long bones, a quality method of geometrical modeling which provides a good result is that of the 3D modeling by reconstruction, using the principles of reverse engineering. One of the important problems that shall be taken into consideration while modeling is the one concerning the real structure of the bones. This aspect presents a lot of importance because from the point of view of the mechanical behavior, the bones are neither homogenate structures. In this paper a study of the long bones structures is undergone, and in relation to the modelated element (the human tibia) it is divided in areas (called constructive-anatomical entities) of different mechanical characteristics and in consequence of this they are being modelated in 3D.

This article presents an experimental approach to the geometrical planning of the medial opening wedge high tibial osteotomy surgery which, as it is known, is an efficient surgical strategy quite widely used in treating knee osteoarthritis. While most of the published papers focus on analyzing this surgery from a medical point of view, we suggest a postoperative experimental evaluation of the intervention from a biomechanical point of view. The geometrical planning and, more specifically, the determination of the point of intersection between the corrected mechanical axis and the medial-lateral articular line of the knee, is a problem quite often debated in literature. This paper aims to experimentally investigate the behavior of the tibia with an open wedge osteotomy fixed with a locking plate, TomoFix (DE Puy Synthes), taking into account two positions of the mechanical axis of the leg on the width of the tibial plateau, measured from medial to lateral at 50% and 62.5% (Fujisawa point), respectively. The variations of the force relative to the deformation, strains, and displacements resulting from the progressive loading of the tibial plateau are studied. The research results reveal that using the Fujisawa point is better for conducting the correction not only for medical reasons, but also from a mechanical point of view.