Background: The safety of simultaneous bilateral total knee
replacement remains controversial. Some studies have demonstrated a higher
rate of serious complications, including death, following bilateral
procedures, whereas others have suggested no increase in the complication
rate. The objective of this meta-analysis was to compare the safety of
simultaneous bilateral total knee replacement with that of staged bilateral
and unilateral total knee replacements.
Methods: A computerized literature search was conducted to identify
all citations, from 1966 to 2005, concerning bilateral total knee replacement.
All of the English-language abstracts were obtained. A multistage assessment
was then performed to identify articles fulfilling the inclusion criteria for
the study. All randomized, prospective studies reporting the outcome of
bilateral total knee replacement were included. The details of the reported
data were extracted, and an extensive analysis of relevant variables was
Results: One hundred and fifty published articles were identified,
and eighteen that included a total of 27,807 patients (44,684 knees) were
included in the meta-analysis. There were 10,930 unilateral total knee
replacements, 16,419 simultaneous bilateral total knee replacements, and 458
staged bilateral total knee replacements with at least three months between
the operative procedures. The prevalences of pulmonary embolism (odds ratio =
1.8), cardiac complications (odds ratio = 2.49), and mortality (odds ratio =
2.2) were higher after simultaneous bilateral total knee replacement. The
prevalence of deep venous thrombosis was lower after simultaneous bilateral
total knee replacement, but this difference was not significant. The
complication rates after the staged bilateral total knee replacements were
similar to those in the patients who had undergone unilateral total knee
Conclusions: Compared with staged bilateral or unilateral total knee
replacement, simultaneous bilateral total knee replacement carries a higher
risk of serious cardiac complications, pulmonary complications, and mortality.
The period of time between staged procedures that would eliminate these
increased risks could not be determined from this study.
Level of Evidence: Therapeutic Level III. See
Instructions to Authors for a complete description of levels of evidence.