A percutaneously implantable orthopedic device is a shape-changing joint prosthesis with a generally arcuate or generally rectilinear configuration which is delivered through a delivery device in a substantially straightened or slightly curved configuration into a joint in a patient. The generally arcuate configuration may include an open ring or spiral shape. The generally rectilinear configuration may include a polygon or zig-zag shape. The delivery and retrieval device can be a syringe, hypodermic needle or cannula. The orthopedic device is moveable into its generally arcuate or generally rectilinear configuration in the joint by manipulation or a shape memory set. The orthopedic device acts as a soft compliant bearing surface or cushion that minimizes the bone-on-bone wear from articulation and loading.