Search results for "Bearing"
showing 10 items of 284 documents
The influence of lateral release on patello-femoral joint loading in knee arthroplasty
1992
Eight fresh, cadaveric knees have been fitted with four different total knee cemented prostheses. Loading forces at the bone implant fixation interface of the patella component have been measured in a knee joint testing rig by four miniaturized force transducers, before and after a lateral release of the patellar retinaculum. The lateral release resulted in a significant local force reduction in the lateral and/or proximal quadrant of the patella resection plane depending on the knee flexion angle, quadriceps tensile force direction, and the patellar prosthesis design.
Transient regional osteoporosis.
2014
Transient regional osteoporosis (TRO) is a disease that predisposes to fragility fracture in weight bearing joints of mid-life women and men. Pregnant women may also suffer the process, usually at the hip. The prevalence of TRO is lower than the systemic form, associated with postmenopause and advanced age, but may be falsely diminished by under-diagnosis. The disease may be uni- or bilateral, and may migrate to distinct joints. One main feature of TRO is spontaneous recovery. Pain and progressive limitation in the functionality of the affected joint(s) are key symptoms. In the case of the form associated with pregnancy, difficulties in diagnosis derive from the relatively young age at pres…
Muscle deficits persist after unilateral knee replacement and have implications for rehabilitation.
2009
BackgroundKnee joint arthritis causes pain, decreased range of motion, and mobility limitation. Knee replacement reduces pain effectively. However, people with knee replacement have decreases in muscle strength (“force-generating capacity”) of the involved leg and difficulties with walking and other physical activities.Objective and DesignThe aim of this cross-sectional study was to determine the extent of deficits in knee extensor and flexor muscle torque and power (ability to perform work over time) and in the extensor muscle cross-sectional area (CSA) after knee joint replacement. In addition, the association of lower-leg muscle deficits with mobility limitations was investigated.Methods…
Morphomechanics of the humero-ulnar joint: I. Joint space width and contact areas as a function of load and flexion angle
1995
BACKGROUND Previous studies have shown that the trochlear notch is deeper than necessary for an exact fit with the humerus. However, humero-ulnar joint space width and contact areas have so far not been quantified for variations in the load and angle of flexion. METHODS Six fresh cadaveric specimens were investigated at 30 degrees, 60 degrees, 90 degrees, and 120 degrees of flexion and at loads of 25 and 500 N, simulating resisted elbow extension. The joint space width and contact were determined, using polyether casting material. RESULTS At 25 N all joints made contact in the ventral and dorsal aspects of the articular surfaces, whereas in the depth of the trochlear notch the joint space w…
Treatment of distal intraarticular tibial fractures: A biomechanical evaluation of intramedullary nailing vs. angle-stable plate osteosynthesis
2015
In factures of the distal tibia with simple articular extension, the optimal surgical treatment remains debatable. In clinical practice, minimally invasive plate osteosynthesis and intramedullary nailing are both routinely performed. Comparative biomechanical studies of different types of osteosynthesis of intraarticular distal tibial fractures are missing due to the lack of an established model. The goal of this study was first to establish a biomechanical model and second to investigate, which are the biomechanical advantages of angle-stable plate osteosynthesis and intramedullary nailing of distal intraarticular tibial fractures. Seven 4(th) generation biomechanical composite tibiae feat…
Two different posterior-stabilized mobile-bearing TKA designs: navigator evaluation of intraoperative kinematic differences
2020
Purpose: The purpose of this study was to compare two types of posterior-stabilized (PS) mobile-bearing (MB) total knee arthroplasties (TKAs). The hypothesis was that no major differences were going to be found among the two TKA designs. Methods: Two cohorts of patients who were divided according to implant design (Cohort A, new design gradually reducing radius PS MB TKA; Cohort B, traditional dual-radius PS MB TKA) were analyzed by means of intraoperative navigation. All operations were guided by a non-image-based navigation system that recorded relative femoral and tibial positions in native and implanted knees during the following kinematic tests: passive range of motion (PROM), varus–va…
The effect of cement fixation on initial micromotion of the femoral component in condylar knee replacement
1992
Four fresh, cadaveric specimens were fitted with total knee replacements and mounted on a knee joint loading and measuring rig. Femoral component micromotion in the sagittal plane was measured with a transducer during flexion and extension of the specimen. Various condylar designs were used without and with cement. Movement followed a characteristic curve pattern and was less with cement fixation particularly for bone of low trabecular strength as determined by bone sample tests for stiffness. Cement fixation appears to be superior to cementless fixation.
The use of pumice lightweight concrete for masonry applications
2011
In the last two decades, the use of pumice as lightweight aggregate for concrete in structural applications has been the object of different studies. The aim was to find out if pumice can be an alternative to ordinary lightweight aggregate. The present paper is framed in this context. Here, a study is presented showing the use of pumice for making lightweight concrete units for masonry members. Through the paper, the formulation of a mix design for lightweight concrete is proposed. Then the obtained mechanical characteristics of the masonry units are discussed and compared to the code requirements. Reinforced bearing masonry walls, made with the concrete masonry units in question, were made…
Time-gated Raman and laser-induced breakdown spectroscopy in mapping of eudialyte and catapleiite
2020
Raman analysis of rock samples containing rare earth elements (REEs) is challenging due to the strong fluorescence, which may mask the weaker Raman signal. In this research, time‐gated (TG) Raman has been applied to the construction of the mineral distribution map from REE‐bearing rock. With TG Raman, material is excited with a short subnanosecond laser pulse, and the Raman signal is collected within a picosecond‐scale time window prior to the formation of a strong fluorescent signal by means of single‐photon avalanche diode array. This allows signal readout with a significantly reduced fluorescence background. TG Raman maps are used to reveal the location of valuable minerals and are compa…
La influencia del estado del partido en la posesión del balón en el fútbol femenino de alto rendimiento
2020
[Abstract] The objective of this study was to examine the effect of the situational match status variable on the ball possession of the teams that participated in the 2015 FIFA Women’s World Cup. The 52 games played during the championship have been collected, and 3,740 ball possessions made by the teams were analyzed. The teams have been divided into successful and unsuccessful. Three types of analysis have been carried out: a univariate analysis for both groups with the categorical and continuous variables selected; a bivariate analysis, using chi-square tests and the exact Fischer test; and finally, a multivariable technique such as the decision trees was incorporated. The available resu…