Primary Total Knee Arthroplasty in Valgus Deformity

Proper limb and component alignments as well as soft tissue balance are vital for the longevity and optimal long-term outcomes of total knee arthroplasty (TKA). The majority of orthopedic surgeons agree that the total arthroplasty procedure in valgus knees with a deformity of more than 10° is technically demanding and may prove challenging. At the time of operation, the bone and soft tissue abnormalities that should be corrected make accurate axis restoration, correct component positioning and joint stability attaining a difficult task. Specific pathologic anatomic changes associated with valgus knee should be understood preoperatively and estimated so as to select the proper surgical method, to enhance component position and to restore soft-tissue balancing. The purpose of this chapter is to consider all the valgus knee anatomical variations, to analyze the best preoperative planning and to evaluate the type of implant, constrained or not. Lastly, it will also be underlying the current main approaches and techniques to be proposed in the literature for both bone cuts and soft tissue management of valgus knees and if minimally invasive techniques can be performed in severe deformed knees

A three-dimensional coupled normal mode model for sound propagation in shallow water with irregular bottom bathymetry.

A three-dimensional (3D) coupled normal mode model for studying sound propagation in a complex coastal environment is developed. This development corresponds to a significant upgrade of an earlier version of the model in which a flat, rigid bottom was used. By imposing the general boundary conditions for an irregular, nonrigid bottom, the coupling coefficient integrals in the system of differential equations governing the mode amplitude are reformulated. The model upgrade entails a numerical implementation of the revised formulae. With the improved physics, this latest version is capable of modeling the 3D acoustic wave-field in shallow water where sound speed, water depth and sediment properties can vary with horizontal location. To demonstrate this enhanced capability, the model is used here to simulate the interactions of the normal modes as they propagate up a sloping bottom.http://archive.org/details/threedimensional00sagoLieutenant J.G., Hellenic NavyApproved for public release; distribution is unlimited