Abstract: An artificial knee has a shock casing and a hinge sheath. Plungers mounted in the shock casing bias the casing and sheath away from each other as a shock absorber mounted in the shock casing controls movement and absorbs shock of the casing and sheath as they move relative to one another. A stem secured to the shock casing passes through the hinge sheath into holes in the roller bearing. In this manner with the sheath and casing are urged toward one another by applying weight to the knee as in walking or kneeling, the stem end moves into the roller bearing to prevent movement of the artificial leg secured to the roller bearing.