Osteotomy literally means "cutting of the bone." In a knee osteotomy, either the tibia (shinbone) or femur (thighbone) is cut and then reshaped to relieve pressure on one compartment of the knee joint. Knee osteotomy is used when a patient has early-stage osteoarthritis that has damaged just one side of the knee joint. By shifting weight off of the damaged side of the joint, an osteotomy can relieve pain and significantly improve function in an arthritic knee.