The medial compartment is realigned by adjusting the angle of the ulna so that the head end thereof is properly aligned with the humerus. The angle of the ulna is adjusted by cutting the ulna below the head. A plate is attached to the ulna to set the new angle. The plate has two parts; one part is straight, the other is angled. Different plates have parts with different angles. A plate with a desired angle is selected to achieve the necessary angle on the ulna. The plate may be attached to the medial side or lateral side of the ulna.