Elbow can also be affected by osteo or rheumatoid arthritis. Elbow joint replacement can effectively treat the problems caused by arthritis of the elbow. The procedure is more widely used in aging adults to replace joints damaged by fractures. In elbow replacement surgery, the painful surfaces of the damaged elbow are replaced with artificial elbow parts. One part fits into humerus (arm bone) and another part fits into ulna (strongest bone in the forearm). The two parts are then connected and held together by a pin. The resulting hinge allows the elbow to bend.