Abstract: An above knee prosthesis comprises an upper block, a lower block, a middle linkage pivotably coupling the middle posterior regions of the upper and lower blocks together, and at least one side linkage pivotably coupling the sides of the upper and lower blocks together. The center of rotation of the prosthesis is located above the prosthesis when it is in full extension and moves downward as the prosthesis rotates into full flexion. When the prosthesis is in use and in full extension, a majority of the weight of the patient borne by the prosthesis is directly transferred from the upper block to the lower block. A bumper disposed between the upper and lower blocks will typically be provided to absorb shock and dampen noise when the prosthesis is in extension. A leaf spring may be provided to bias the prosthesis to be in extension.