Counting on a Total Hip Replacement

Epidemiologists study the big picture of disease. They look at data to find out how a disease affects the population as a whole. Epidemiology doesn't just produce facts about disease. It also gives information about how the health care system works.

This article is about the Epidemiology of total hip replacement (THR) in the United States. The authors analyzed data from Medicare records of people 65 or older over the course of one year. They focused on patients who had THR or revision THR surgery, but not because of hip fractures, hip infections, or cancer. The authors discovered some interesting facts about THR.

  • The highest rates of THR were in the mountain and northwest areas. The lowest rates were in the south.
  • More women had THR than men.
  • Whites had more THR surgeries than blacks. This was true even when controlling for income and other factors.
  • There were up to six times as many primary THR surgeries as revision THR surgeries.
  • The rate of primary THR increased until age 79 and then declined. The rate of revision THR increased until age 84 and then declined.
  • Within 90 days of primary THR surgery, one percent of patients died; nearly one percent had a pulmonary embolus (blood clot that enters the lung); 0.2 percent had a wound infection; 4.6 percent were readmitted to the hospital; and just over three percent dislocated the hip.
  • Within 90 days of revision THR, the rates for complications were about twice as high. This was true for all complications except pulmonary embolus, which happened at about the same rate.
  • Poor outcomes were more likely for men, blacks, older people, and those with other medical problems or a low income.

    By themselves, these numbers don't really tell doctors anything. But combined with other data, these facts give health professionals information that can help them provide better care.



    References: Nizar N. Mahomed, MD, ScD, FRCSC, et al. Rates and Outcomes of Primary and Revision Total Hip Replacement in the United States Medicare Population. In The Journal of Bone and Joint Surgery. January 2003. Vol. 85-A. No. 1. Pp. 27-32.