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The performances of high-speed machine tools depend not only on the speed, power, torque, dynamic and static stiffness, but also on the thermal behavior of the spindle. These parameters directly affect the productivity and quality of machining operations. This paper presents a 3-D finite element thermal model, which was based on the thermo mechanical bearing model and the numerical model of the spindle. Based on thermo mechanical analysis of bearings with angular contact, generated heat and thermal contact resistance are determined for each position of the ball. To provide the most accurate analysis possible in determining thermal contact resistance , bearings are divided into several zones based on the geometry of their cross-section. The aforementioned constraints have been applied to the 3-D FEM model which allowed for establishing temperature field distribution, and spindle thermal balance. In order to prove the efficacy of the proposed model, experimental measurements of spindle and bearing temperatures were done by using thermocouples and thermal imager.

The success of the hip arthroplasty surgery largely depends on the endoprosthesis adjustment to the patient's femur. This implies that the position of the femoral bone in relation to the pelvis is preserved and that the endoprosthesis position ensures its longevity. Dimensions and body shape of the hip joint endoprosthesis and its position after the surgery depend on a number of geometrical parameters of the patient's femur. One of the most suitable methods for determination of these parameters involves 3D reconstruction of femur, based on diagnostic images, and subsequent determination of the required geometric parameters.In this paper, software for automated determination of geometric parameters of the femur is presented. Detailed software development procedure for the purpose of faster and more efficient design of the hip endoprosthesis that ensures patients' specific requirements is also offered.

The tibial tunnel aperture surface area differs significantly from the ellipse surface area, which is commonly used in the anterior cruciate ligament reconstruction analysis. Inclusion of the 3D shape of the tibial attachment site in the preoperative anterior cruciate ligament reconstruction planning process can lead to a more precise individual anatomic anterior cruciate ligament reconstruction on the tibial bone. Both tibial aperture area generated in 3D and its projection on a tibial plateau are larger than the ellipse surface; therefore, individual characteristics of each patient have to be taken into consideration.

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Anterior cruciate ligament (ACL) is the most common surgically treated knee ligament. If we take into account the fact that incidence of ACL injuries is growing, it is clearly that the interest of orthopedic surgeons for this pathology is also growing. Increasing number of this operations leads to increasing of complications, which requires its analysis. One of the most common failure of ACL reconstruction is a bad position of the graft in the femoral condyle. This study aimed to analyze the positioning of the graft in to the femur by two generally accepted techniques--transtibial technique and technique through the antero-medial portal. The analysis included postoperative radiographs in 60 patients, of whom 30 were operated by transtibial technique and 30 by technique through anteromedial portal. Radiographic analysis involved the measurement of the AP digital imaging, the tunnel projection X ray measurements and measurements of the computed tomography (CT), which was here a control method. The accuracy of measurement was set at 0.5 degrees or 1 min. All radiographs were made in the same way according to the literature. The results showed that the neoligaments were placed lower in the femoral condyle by technique through anteromedial portal than by transtibial technique, and the difference was statistically significant (on tunnel X ray by anteromedial portal screws were average placed at 50.0 degrees and 10:20 am, and by transtibial technique at 37.5 degrees or 10:45 am). Based on the results, it was concluded that the neoligaments were positioned closer to its anatomical position by technique through anteromedial portal.