Mary, a 52-year-old woman, was admitted for a right total hip arthroplasty. She had taken early retirement from her job as a bus conductress. She had worked on double-decker buses for the past 15 years and had found it increasingly difficult to manage the stairs. Her condition became severe enough to prohibit her working, as she suffered a great deal of intractable pain both day and night. The pain and unstable nature of her movements necessitated the use of a walking stick for support. She was rather obese, but had managed to lose half a stone before admission.