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Elderly knee replacement patients fare better when treated in more experienced hospitals

Elderly patients undergoing total knee replacement (TKR) surgery at hospitals that perform at least 50 of these operations each year are less apt to suffer complications than those who undergo the procedure at hospitals that perform fewer TKRs. These are the findings of a recent study by the Total Knee Replacement Patient Outcomes Research Team (PORT). The study involved Medicare patients who underwent knee replacement surgery between 1985 and 1990. The TKR PORT was supported by the Agency for Health Care Policy and Research (HS06432).

These findings suggest that knee surgery should not be expanded to small hospitals; instead it should be centralized at regional centers where at least 50—and preferably 100—operations each year are assured. This is one way to reduce in-hospital complications, according to the PORT researchers. They analyzed 6 years of Medicare claims data and other data files for patients who underwent primary knee replacement from 1985 to 1990. Models were used to estimate the probability that a patient would have an in-hospital complication. The models controlled for hospital volume, other hospital characteristics, patient demographics, and patient health status. A panel of two orthopedic surgeons and two internists reviewed diagnosis codes to determine whether a complication was likely, possible, or due to anemia.

The researchers calculated that increasing the number of annual hospital knee replacement operations from 40 to 80 would decrease the probability of a likely complication for Medicare patients by about 3 percent. Including younger patients would increase the thresholds for total volume to 53 and 107. The most likely complications were disorders of fluid, electrolyte, and acid-base balance; cardiac dysrhythmias; complications affecting specified body systems; and rupture of a tendon.

For more details, see "The effect of hospital volume on the in-hospital complication rate in knee replacement patients," by Edward C. Norton, Ph.D., Steven A. Garfinkel, Ph.D., Lisa J. McQuay, and others, in the December 1998 Health Services Research 33(5), pp. 1191-1210.

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