Estimation of Ligament Loading and Anterior Tibial Translation in Healthy and ACL-Deficient Knees During Gait and the Influence of Increasing Tibial Slope Using EMG-Driven Approach

The purpose of this study was to develop a biomechanical model to estimate anterior tibial translation (ATT), anterior shear forces, and ligament loading in the healthy and anterior cruciate ligament (ACL)-deficient knee joint during gait. This model used electromyography (EMG), joint position, and force plate data as inputs to calculate ligament loading during stance phase. First, an EMG-driven model was used to calculate forces for the major muscles crossing the knee joint. The calculated muscle forces were used as inputs to a knee model that incorporated a knee–ligament model in order to solve for ATT and ligament forces. The model took advantage of using EMGs as inputs, and could account for the abnormal muscle activation patterns of ACL-deficient gait. We validated our model by comparing the calculated results with previous in vitro, in vivo, and numerical studies of healthy and ACL-deficient knees, and this gave us confidence on the accuracy of our model calculations. Our model predicted that ATT increased throughout stance phase for the ACL-deficient knee compared with the healthy knee. The medial collateral ligament functioned as the main passive restraint to anterior shear force in the ACL-deficient knee. Although strong co-contraction of knee flexors was found to help restrain ATT in the ACL-deficient knee, it did not counteract the effect of ACL rupture. Posterior inclination angle of the tibial plateau was found to be a crucial parameter in determining knee mechanics, and increasing the tibial slope inclination in our model would increase the resulting ATT and ligament forces in both healthy and ACL-deficient knees

Cuidados paliativos: interfaces, conflitos e necessidades Palliative care: interfaces, conflicts and necessities

O tipo de assistência prestado para pacientes com doenças avançadas e terminais tem sido objeto de intenso debate na literatura especializada. Este artigo descreve e analisa, a partir de revisão da literatura, as intervenções possíveis no fim da vida, com especial ênfase aos cuidados paliativos, um modelo em expansão no mundo. Analisa, a partir de uma perspectiva bioética, alguns dos aspectos moralmente relevantes que envolvem estas práticas, que tendem a ser conflituosas entre si, e, especificamente, dentro do campo dos cuidados paliativos, destaca certas dificuldades e desafios em torno da centralidade da autonomia, considerada um dos pilares para boas práticas de cuidados no fim da vida.<br>The kind of care delivered to patients with advanced and terminal diseases has been under intense debate in the specialized literature. This paper describes and analyzes, on the basis of a bibliographic review, medical care practices at the end of life, with special emphasis to palliative care, a model expanding worldwide. It analyzes, from the perspective of bioethics, some morally relevant aspects involving these practices, that tend to conflict among themselves. Specifically in the field of palliative care the paper emphasizes certain difficulties and challenges involving autonomy, considered one of the cornerstones of good end of life care practices