Studying the Safety of Doing Two Knee Replacement Surgeries at the Same Time

About one-third of people with arthritis of the knee have the problem in both knees. This can be a big problem when it’s time for knee replacement surgery. In the past, the only option was surgery on one knee at a time, with several months in between. But two separate surgeries double the risk of complications. Two surgeries mean more time in the hospital and more time in rehab. Two surgeries also increase costs.

In the past 10 years or so, some surgeons have been doing both knee replacement surgeries at the same time. This is called bilateral total knee replacement. (Doing just one knee is called unilateral surgery.) Many studies are being done to determine how safe and effective bilateral knee replacement surgery really is.

This study compared 92 patients who had bilateral knee replacement with 92 patients who had unilateral knee replacement. All the knee replacements used the same types of implants. The bilateral surgeries were done with two teams of surgeons. Both knees were worked on at the same time to shorten the time under anesthesia. Shorter anesthesia times usually mean fewer complications.

All patients were followed for at least three years after surgery. Some patients were followed for seven to eight years. Researchers looked for complications and asked questions about satisfaction with the surgery. Researchers also looked at the patients’ health records from before surgery.

There were some interesting comparisons:

  • Bilateral patients still spent more time in surgery: an average of 126 minutes, compared to 97 minutes for the unilateral patients.
  • Bilateral patients also spent more days in the hospital. However, they did not stay twice a long as unilateral patients.
  • The two groups had similar low rates of surgical complications such as infections. The two groups also had similar low rates of revision surgery.
  • More patients in the bilateral group had pneumonia and heart problems after surgery. However, more patients in the bilateral group were in poor overall health before surgery.
  • There was only one death in the study. The patient who died was in the bilateral group. This patient had severe health problems before surgery.
  • Of the bilateral group, 95 percent say they would do it the same way if they had to choose again.

    The authors conclude that bilateral knee replacement is at least as safe as unilateral replacement. They stress that anesthesia times must be kept low, especially for patients in poor health. The authors recommend future research into ways to make bilateral knee replacement as safe as possible.