If you need a prosthetic limb, then you don't have to use traditional casting processes. You can now use a hydrostatic design process. Here, you put the affected limb into a special hydrostatic chamber device. The device uses water pressure to create an impression of the space that the limb will fill and its connections to your body. What are the advantages of hydrostatic prosthetic casting? Incorporate Load-Bearing Weight While regular prosthetic casting processes can create limbs that fit, they don't always work perfectly.