Knee disarticulation is a muscle balanced amputation level that can be used in patients with diabetes, peripheral vascular disease, and trauma. Patients who are capable of sitting in a chair retain an excellent platform for sitting, a lever arm for transfer, and are unlikely to have joint contractures develop. In patients who are ambulatory and have vascular disease and in patients with trauma, this amputation level provides a well padded residual limb that allows distal endbearing. The use of a four bar linkage prosthetic knee joint confers intrinsic knee joint stability during walking.