There is shown an artificial joint (1), which joint has a first part (11) adapted to be attached at a wearer's first body part or substitute body part, and a second part (12) adapted to be attached to a second body part or substitute body part, wherein the first part (11) and the second part (12) can be rotated relatively each other and are connected to each other by means of at least four shafts (21, 22, 23, 24) and corresponding links (13, 14, 15). The joint (1) is characterised in that it is freely moveable when the joint is unloaded by the wearer, and in loaded position the same joint is geometrically locked.