X-ray image of the pelvic area after surgery to replace the patient's right hip joint, which was severely damaged by rheumatoid arthritis which the young man succumbed to in infancy. The prosthesis needs no pointing out. Both hip joints were affected with the disease but the severity of the case meant that surgeons could only replace one joint at a time; in less severe cases a bilateral replacement might be performed at the same time. This X-ray is one of a before and after surgery series.