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Staggering Knee Replacements Appears Safer than Having Two Done at Once

Total knee arthroplasties, or knee replacements, are popular and effective orthopedic surgeries. They have a good safety record and are quite effective in most cases. However, for patients who require replacements for both knees, there is controversy regarding whether they should be done at the same time, simultaneously, or in two separate surgeries.

In this study, a review of the literature, investigators found 18 previously done studies that encompassed 27,807 patients and 44,684 total knee replacements. Of the replacements, 16,419 were simultaneous bilateral procedures (both at the same time) and 458 were staged bilateral procedures.

Of the 18 studies, six reported on findings of deep vein thrombosis, clots in the blood system, 11 on pulmonary embolism, clots in the lungs, eight on heart complications, and eight on the rate of death.

The investigators found that there were no significant differences between having both knees done at the same time and the staged procedures when looking at the rate of deep vein thrombosis, but there was a significant difference with rates of pulmonary embolism. In some studies, the odds ratio for pulmonary embolism was seven times higher among patients who had the simultaneous procedures over those who did not. When the investigators looked at the heart complications, although there were more in the simultaneous group, the differences weren't major between the two. Finally, when assessing mortality, this was found to be significantly higher among the simultaneous procedure group. The odds ratio among these patients was found to be as high as 10.15 in one study.

The researchers concluded that, although most patients who need a knee replacement only need one done, there remain many who need both. While it may seem better to do both at the same time because of only one hospitalization, one time under anesthetic, etc., it may be that it isn't in the patients' best interest to do simultaneous replacements. The researchers also point out that knowing the adverse outcomes of many simultaneous procedures, surgeons should be made aware and then perhaps limit the simultaneous procedures to patients who do not have cardiac conditions.

More studies do need to be done on this topic, the authors say.

References: Camilo Restrepo et al. Safety of Simultaneous Bilateral Total Knee Arthroplasty. A Meta-Analysis. In The Journal of Bone & Joint Surgery. June 2007. Vol. 89. No. 6. Pp. 1222-1226.

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