7/29/2023 0 Comments Complete anatomy of the kneeThe dissection of its superficial component determines a significant increase of the deviation in valgus between 0° and 45° of flexion, as well as external rotation. The primary function of the MCL is to prevent a deviation of the knee during valgus stress. The opposite happens during the extension. During flexion of the knee, the superficial vertical fibres are taut, while the posterior and deep are unstretched. The MCL is composed of two layers: superficial and deep. Most of the extracellular matrix proteins are composed of type II collagen and aggrecan, a proteoglycan that binds glycosaminoglycans.Ī disruption of this equilibrium determines modifications of biochemical and biomechanical cartilage properties with consequent alterations of its tensile capacities and less possibility of loads absorption. The chondrocytes are the most represented cells of the cartilage and are specialized in the synthesis, organization and turnover of extracellular matrix proteins. In the normal cartilage a close correlation between structure and biochemical composition, orientation of the fibrils and its biomechanical properties is present. The superficial layers of cartilage function like deformable bearings and thanks to their visco-elastic properties better distribute the loads across the joint. The articular components of the femur, tibia and patella, which articulates with the femoral trochlea, are covered with hyaline cartilage that allows skeletal elements to slide and rotate one above the other with a low friction. The geometric shape of the condyles is the most important factor for the stability of the knee under loads. This structure contains two tubercles on which the cruciate ligaments have their origin, thus contributing to fix the femur on the tibia. Therefore, the two tibial surfaces, which present a double concave curvature in the frontal aspect, are divided by the intercondylar eminence. However, both femoral condyles are convex in the frontal and sagittal plane. The medial tibial plateau is biconcave, unlike the lateral that is concave on the front plane and convex in the sagittal plane. The articular surfaces of the knee are curved and represented by the medial and lateral femoral condyles, which are connected with the corresponding tibial plateaus. However, until the current date, it has not been possible to produce a prosthetic design fully restoring the complex kinematics of the normal knee joint. The various choices imply that each specific problem has a corresponding implant that provides a reliable solution. There are a number of types of total knee arthroplasty implant designs, which are intended to offer the surgeon options for individual patients. In the last decades comprehension of knee physiology and kinematics has led to the introduction of a wide range of enhanced prosthetic implant designs for a variety of indications. The understanding of anatomy and knee biomechanics is important for the gait analysis, the diagnosis of joint diseases and the design and development of prosthetic implants. Under normal conditions there is a normal distribution of the load forces on these three articular components in both the static load and during ambulation. The knee is the intermediate joint of the lower limb and it allows the movement between the femur, tibia and patella.
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