Femoral osteotomy. Coloured X-ray showing a femoral osteotomy, performed as treatment for osteoarthritis of the hip. Osteoarthritis is a common joint disease aggravated by mechanical stress. It is characterised by degeneration of the cartilage that lines joints or by formation of osteophytes (bony outgrowths) which lead to pain, stiffness and loss of joint function. In a femoral osteotomy the femur (thigh bone) is cut just below the hip joint and the two ends are realigned and fixed with a steel pin (white). The operation allows weight to be carried through a different, less damaged, portion of the articular cartilage.