Issue: January 2014
January 01, 2014
2 min read

Simultaneous bilateral TKA more cost effective than staged bilateral TKA

Complication rates and in-hospital mortality rates were also higher in staged bilateral total knee arthroplasty.

Issue: January 2014
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Researchers discovered higher costs, complication and in-hospital mortality rates associated with staged bilateral total knee arthroplasty compared to simultaneous bilateral total knee arthroplasty.

“Simultaneous bilateral total knee arthroplasty was more cost effective than staged bilateral total knee arthroplasty using this data set,” Susan M. Odum, PhD, senior research scientist at OrthoCarolina Research Institute, Inc., in Charlotte, told Orthopedics Today. The results of the cost-utility analysis conducted by Odum and colleagues were recently published in the Journal of Bone & Joint Surgery.

Higher cost to society

The researchers used the National Inpatient Sample Database to identify 381,002 unilateral total knee arthroplasties (TKAs) and 24,020 simultaneous bilateral TKAs performed between 2004 and 2007. The investigators used propensity matching to create two cohorts that were similar with respect to demographics, health status and other factors. The average patient age was 67 years for the staged group and 65 years for the simultaneous group.

“We considered cumulative costs and utility values for 15 years following the year of surgery with use of a 3% discount rate,” the authors wrote in their study. The mean total cost was $65,297 for staged bilateral TKA vs. $43,245 for simultaneous bilateral TKA. However, the investigators discovered no statistically significant difference for the quality-adjusted life years gained in either group.

According to Odum, the rate of minor complications was 8.98% for staged TKA and 6.84% for simultaneous bilateral TKA. The minor complication rate was 2.36% for staged group vs. 1.49% for the simultaneous cohort. The in-hospital mortality rate was also higher for the staged group compared to the simultaneous bilateral group (0.20% vs. 0.18%).

“For surgeons and patients who are faced with making the decision whether to do both total knees at the same time, it is more cost effective to do both knees at once,” Odum said. “It may not be the right decision for every patient, doctor or setting, but if it is a viable option, it should be considered.”

Study limitations

Odum said the study was limited by its observational design, potential coding errors in the claims data and lack of long-term complication data.

“We did not take into consideration a number of societal costs, such as costs of family care giving and lost wages and a lack of a true staged cohort can be problematic,” Odum said. The researchers are considering a study that uses a new data set with a linking variable to a true staged population on a large scale, according to Odum.

“Much of the research done in this area have been small studies with a single surgeon, so having a large data set with hundreds of thousands of observations is great because the data is precise,” Odum said. – by Renee Blisard Buddle

Odum S. J Bone Joint Surg. 2013;doi:10.2106/JBJS.L.00373.
For more information:
Susan M. Odum, PhD, can be reached at Ortho-Carolina Research Institute Inc., 2001 Vail Ave., Suite 300, Charlotte, NC 28207; email:
Disclosure: Odum has no relevant financial disclosures.