Two Knee Replacements May Be Better Than One

Simultaneous total knee replacement (TKR) in both knees is associated with significantly fewer prosthetic joint infections as well as other revision knee operations within one year after surgery, according to a new study.

Researchers at the University of California (UCD; Davis, USA) followed 11,445 patients who underwent simultaneous bilateral TKR, and 23,715 patients who had both knees replaced in two stages several months apart. The patients' mean ages were 67.2 years in the group who underwent simultaneous surgery, and 67.7 years in the group who underwent two surgeries. The majority of patients in both groups were women: 53.9% in the simultaneous surgery group and 61.3% in those that underwent two procedures.

The results showed that the risk of developing a serious joint infection requiring an additional knee revision surgery was twice as high in patients who had staged knee replacements (2.2%), compared to the patients who had simultaneous TKR (1.2%). On the other hand, simultaneous TKR was also associated with a moderately higher risk of adverse cardiovascular events such as myocardial infarct (MI), pulmonary embolism, or thrombosis, but there was no significant difference in overall mortality. The study was presented at the 2011 annual meeting of the American Academy of Orthopaedic Surgeons (AAOS), held during February 2011 in San Diego (CA, USA).

"These findings indicate that performing simultaneous knee replacements would significantly reduce the incidence of major orthopedic complications, and at the same time reduce the number of hospitalizations and the number of operating room sessions,” said lead author and study presenter John Meehan, MD, an orthopedic surgeon at UCD.

TKR is surgery to replace a damaged or diseased knee joint with an artificial joint, or prosthesis. The procedure is performed under general anesthesia (GA) or regional anesthesia, and involves the replacement of the articular surfaces of the femoral condyles, the tibial plateau, and the patella; the anterior cruciate ligament is also excised. The new knee prosthesis consists of a joint shell replacing the acetebulum and the articular surfaces. The surgery itself takes about 2 hours.

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