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A Population-Based Comparison of the Incidence of Adverse Outcomes After Simultaneous-Bilateral and Staged-Bilateral Total Knee Arthroplasty
John P. Meehan, MD1; Beate Danielsen, PhD4; Daniel J. Tancredi, PhD5; Sunny Kim, PhD2; Amir A. Jamali, MD3; Richard H. White, MD6
1 Department of Orthopedic Surgery, University of California, Davis, 2801 K Street, Suite 310, Sacramento, CA 95816
4 Health Information Solutions, 2545 Clubhouse Drive, Rocklin, CA 95765
5 Center for Healthcare Policy and Research, 2103 Stockton Boulevard, Suite 2224, Sacramento, CA 95817
2 University of California, Davis, CTSC Annex, Room 1117, 2921 Stockton Boulevard, Sacramento, CA 95817
3 Joint Preservation Institute, 2825 J Street #440, Sacramento, CA 95816
6 Department of Medicine, University of California, Davis, Suite 2400, PSSB, 4150 V Street, Sacramento, CA 95817
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Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. In addition, one or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.

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Investigation performed at the University of California, Davis, School of Medicine, Sacramento, California

Copyright © 2011 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2011 Dec 07;93(23):2203-2213. doi: 10.2106/JBJS.J.01350
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It is unclear whether simultaneous-bilateral total knee arthroplasty is as safe as staged-bilateral arthroplasty is. We are aware of no randomized trials comparing the safety of these surgical strategies. The purpose of this study was to retrospectively compare these two strategies, with use of an intention-to-treat approach for the staged-bilateral arthroplasty cohort.


We used linked hospital discharge data to compare the safety of simultaneous-bilateral and staged-bilateral knee arthroplasty procedures performed in California between 1997 and 2007. Estimates were generated to take into account patients who had planned to undergo staged-bilateral arthroplasty but never underwent the second procedure because of death, a major complication, or elective withdrawal. Hierarchical logistic regression modeling was used to adjust the comparisons for patient and hospital characteristics. The principal outcomes of interest were death, a major complication involving the cardiovascular system, and a periprosthetic knee infection or mechanical malfunction requiring revision surgery.


Records were available for 11,445 simultaneous-bilateral arthroplasty procedures and 23,715 staged-bilateral procedures. On the basis of an intermediate estimate of the number of complications that occurred after the first procedure in a staged-bilateral arthroplasty, patients who underwent simultaneous-bilateral arthroplasty had a significantly higher adjusted odds ratio (OR) of myocardial infarction (OR = 1.6, 95% confidence interval [CI] = 1.2 to 2.2) and of pulmonary embolism (OR = 1.4, 95% CI = 1.1 to 1.8), similar odds of death (OR = 1.3, 95% CI = 0.9 to 1.9) and of ischemic stroke (OR = 1.0, 95% CI = 0.6 to 1.6), and significantly lower odds of major joint infection (OR = 0.6, 95% CI = 0.5 to 0.7) and of major mechanical malfunction (OR = 0.7, 95% CI = 0.6 to 0.9) compared with patients who planned to undergo staged-bilateral arthroplasty. The unadjusted thirty-day incidence of death or a coronary event was 3.2 events per thousand patients higher after simultaneous-bilateral arthroplasty than after staged-bilateral arthroplasty, but the one-year incidence of major joint infection or major mechanical malfunction was 10.5 events per thousand lower after simultaneous-bilateral arthroplasty.


Simultaneous-bilateral total knee arthroplasty was associated with a clinically important reduction in the incidence of periprosthetic joint infection and malfunction within one year after arthroplasty, but it was associated with a moderately higher risk of an adverse cardiovascular outcome within thirty days. If patients who are at higher risk for cardiovascular complications can be identified, simultaneous-bilateral knee arthroplasty may be the preferred surgical strategy for the remaining lower-risk patients.

Level of Evidence: 

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
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    John P. Meehan, M.D., Beate Danielsen, PhD, Daniel J. Tancredi, PhD, Sunny Kim, PhD, Amir A. Jamali, M.D., Richard H. White, M.D.
    Posted on February 22, 2012
    Response to Gaines et al.
    U.C. Davis Health System

    We appreciate the positive comments provided by Gaines et al. regarding our study. As is stated in our article, we identified patients having undergone simultaneous-bilateral total knee arthroplasty by using administrative codes, in this case 81.54, when two primary total knee procedure codes were entered on the same day. Unfortunately administrative codes are unable to capture the effect of individual surgeons, such as would occur if two surgical teams performed the knee replacements at the same time, or if one surgical team performed them sequentially. We agree that a well done study to compare simultaneous-bilateral total knee replacements performed by two surgical teams concurrently or one surgical team sequentially would add to the present literature on the topic.

    Steven T. Gaines, M. D., Robert N. Steensen, M. D., Craig N. Dimitris, M. D., Benjamin C. Taylor, M. D., and John G. Mowbray, M. D.
    Posted on February 18, 2012
    Sequential or simultaneous bilateral arthroplasty; differences in outcomes?
    Mount Carmel Health System, Columbus, Ohio and The Cardinal Orthopaedic Institute, Columbus, Ohio

    We would like to commend Meehan and co-authors for this article, which provides significant data regarding the safety of bilateral TKA in general.We feel there is one other important question to raise and answer. Simultaneous procedures are listed as those performed during the same surgical session. This would most likely include arthroplasties performed by one surgeon, first one knee then the other, but could also include those performed by two surgeons at the same time. These were not specifically differentiated in the article as either sequential or simultaneous bilateral TKA. Using this specific terminology, we recently reported a series of two-team (two surgeon) simultaneous bilateral knee arthroplasty (Orthopedics. 2011; 34:944). One goal of that paper was to further clarify the terminology regarding the more generic label of bilateral total knee arthroplasty. We termed bilateral total knee arthroplasty performed by two surgeons at the same time as simultaneous, and termed bilateral total knee arthroplasty performed by one surgeon, first one knee then the other, as sequential. This distinction was previously defined by other authors, including A. J. Tria, Jr., David A. Harwood, and Jose A. Alicea (in Fu, F. H. Knee Surgery. Williams & Wilkins: 1994:1275-1280.). We feel the distinction is important as the risks for each may differ in incidence. The duration of a procedure, for example, is felt to affect the risk of complications. Two surgeons performing a simultaneous bilateral total knee arthroplasty would routinely complete the surgery in a shorter time than one surgeon performing both knees sequentially. We ask if the authors could distinguish between those patients who received same day bilateral total knee arthroplasty as either having one surgeon perform the procedure on both knees sequentially versus those having two surgeons operating at the same time on separate knees with separate teams- simultaneous? We feel this separation of the bilateral total knee arthroplasty group into sequential and simultaneous subgroups would significantly add to the literature on this topic, as the complication rate of these distinct groups could then be legitimately determined. Again, we commend the authors on the magnitude of their undertaking and look forward to further research in this area. DISCLOSURE: The authors did not receive any outside funding or grants in support of his research for or preparation of this work. Neither they nor a member of the immediate family received payments or other benefits of a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct any benefits to any research fund, foundation , division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of the immediate family, are affiliated or associated.

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