Clinical Decisionmaking

Patients and doctors need to weigh the risks and benefits of simultaneous versus staged bilateral knee replacement

Arthritis of the knee is common, particularly among the elderly. Total knee replacement (TKR) surgery is frequently used to alleviate pain and improve function in patients with severe knee arthritis. For patients with problems in both knees, there are advantages to having both knees replaced in a single procedure (simultaneous bilateral TKR), according to a study by the Total Knee Replacement Patient Outcomes Research Team (PORT), which was supported by the Agency for Healthcare Research and Quality (HS06432).

The researchers found that patients who underwent simultaneous bilateral TKR had about 20 percent lower risk of reoperation than those who underwent staged bilateral TKR (both knees replaced in two staged procedures). Nevertheless, the reoperation rates were low for both groups, less than 1 percent at 2 years.

Cumulative mortality rates were about 0.5 percent higher for the simultaneous versus staged surgery group at 1 month (0.99 percent versus 0.38 percent) and 6 months (1.93 percent versus 1.39 percent). This difference was reduced by half at 1 year, and the rates were nearly the same by 2 years. Other studies have shown that the simultaneous approach has a lower complication rate (for example, postoperative wound infection or hemorrhage), lower total cost, and shorter hospital stay compared with staged bilateral TKR.

The researchers point out that patients and their doctors need to balance the risks and benefits of simultaneous bilateral TKR versus staged bilateral TKR when making the knee replacement decision. The PORT was led by Deborah A. Freund, Ph.D., M.P.H., formerly of Indiana University and now with Syracuse University. The researchers retrospectively analyzed 1985 to 1990 Medicare data on 11,771 Medicare enrollees who underwent bilateral simultaneous or staged TKR between 1985 and 1988.

More details are in "Revision rates following staged and simultaneous bilateral knee replacement," by Barry P. Katz, Ph.D., Ziao-Hua Zhou, Ph.D., Sujuan Gao, Ph.D., and others in the September 1999 Journal of Clinical Outcomes Management 6(8), pp. 30-34.

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