Knee osteotomy. Artwork of a bone tool being used during an osteotomy operation on the knee. An osteotomy involves the removal of bone, and in the case of the joints is usually done as part of the implantation of an artificial joint. Here, the head of the tibia is beaing removed. Also visible is the fibula (right), the patella (knee-cap, grey), the femur (thigh bone, top), and various knee ligaments. The head of the tibia is being removed above the femoral ligaments attachment points.