Abstract: This invention relates to an artificial leg comprising an elongated lower leg portion, an ankle joint, an upper portion adapted to strap to the wearer's thigh, a knee joint comprising an upper and lower cam, the upper cam adapted to rotate around a pivot and having a convex shape and a lower cam having a concave shape and an elongated arm portion which locks into the upper cam when pressure is placed on the leg and releases by spring action when pressure is released from the leg.