Pinned arthritic hip. X-ray of a patient with a pinned femur (thigh bone) after an osteotomy to treat osteoarthritis of the hip. The femur was cut in two just below its head (white area) and the two ends were realigned. The operation allows weight to be carried through a different, largely undamaged, portion of the articular cartilage, thus reducing pain and disability in the joint. Osteoarthritis is a degenerative joint disease that results in the loss of cartilage between the joint and the growth of bone in place of the cartilage.