Complication rate twice as high for bilateral than unilateral TKA

Issue: November 2010

Despite the growing popularity of bilateral total knee arthroplasty, surgeons and patients alike should be well informed about the increased risk of complications from the procedure, as opposed to scheduling each knee separately, according to researchers.

A retrospective cohort analysis of 150 patients with unilateral (control) total knee arthroplasty (TKA) compared to 150 patients with sequential bilateral TKA found that the mean overall short-term complication rate was roughly 2.1 times greater in the bilateral group.

Although there was no significant difference in complication rates between patients aged 50- to 69-years old for both groups, patients in the bilateral group who were 70 years and older had a significantly increased risk for morbidity, said authors David Fabi, MD, a former joint replacement fellow at Rush University in Chicago and current adult reconstruction specialist at San Diego Orthopaedic Associates Medical Group, and Vivek Mohan, MD, a clinical fellow and junior faculty in orthopedics spine surgery at the University of California, Davis. Bilateral patients between the age of 70- and 79-years old had a 3.5 higher complication rate than their unilateral counterparts, whereas bilateral patients 80 years old and older were three times as likely to develop complications.

Not major complications

“These complications may not be major, such as increased ICU stay, but definitely there was a trend of increased stay in the hospital, more blood transfusions, other site infections like a urinary tract infection (UTI) or pneumonia, and slower overall rehabilitation,” Mohan told Orthopedics Today. The rate of transfusion was 3.9 times higher in the bilateral cohort and length of hospital stay was 1.6 days longer — typically 4 to 5 days, compared to 3 to 4 days for the unilateral group.

The 2- to 3-year outcomes data showed no deaths, “so we cannot comment on mortality,” Mohan said.

Fabi published these findings in the Journal of Arthroplasty, moreover, the results were presented at the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in New Orleans by Mohan when he was a senior resident at the University of Illinois in Chicago, where the study was conducted.

Comorbid conditions

“Patients who underwent bilateral surgery with comorbidities such as obesity, smoking and pulmonary disorders carried nearly a threefold risk of complications compared to unilateral TKA,” Mohan said. “Obesity was not the biggest factor, although we operated on a lot of obese patients. It was really smoking and heart risk.”

Still, patients with a body mass Index (BMI) exceeding 30 were at nearly double the risk for complications if they had bilateral TKA vs. unilateral TKA: 0.97 vs. 0.44. In addition, bilateral patients with pre-existing pulmonary disorders had 1.5 times relative risk of having complications as opposed to those without pulmonary disorders.

“If you are going to schedule bilateral surgery, discuss the options with the patient,” Mohan said. “The patient should be told that the two knees can be done on separate days. But for those patients who opt to have both knees done on the same day, they should understand the increased risk if they are obese, smoke or have cardiac considerations, or if they are 70 years old or older.”

Fabi told Orthopedics Today, “Our study is a contribution to the growing body of literature on this subject and further extrapolates on potential risk factors for adverse events with simultaneous procedures. It is imperative, however, for surgeons and patients alike to be aware that there is still a place for simultaneous bilateral total knee arthroplasty in the appropriately selected patient. There is something to be said about less overall hospital cost, less potential time off of work for the patient and less overall rehabilitation time. In addition, let us not forget about patients with bilateral flexion contractures who would benefit immensely from simultaneous surgeries. But, again, the surgeon must weigh the benefits and disadvantages and ultimately, do what is best for the patient.”– by Bob Kronemyer

References:

Fabi DW, Mohan V, Goldstein WM, et al. Unilateral vs. bilateral total knee arthroplasty risk factors increasing morbity. J Arthroplasty. 2010;Sept. [Epub ahead of print]

Mohan V, Goldstein WM, Fabi DW, et al. Unilateral versus bilateral total knee arthroplasty: risk factors increasing morbidity. Paper 683. Presented at the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons. March 9-13. New Orleans.

David Fabi, MD, is an adult reconstruction specialist and general orthopedic surgeon, he can be reached at the San Diego Orthopaedic Associates Medical Group; e-mail: dfabilus@gmail.com

Vivek Mohan, MD, can be reached at 4860 Y St., Suite 3800, Sacramento, CA 95817; 916-734-2937; e-mail: vivek.mohan@ucdmc.ucdavis.edu.

Michael P. Bolognesi

This article adds more data to support the increased incidence of complications that can be seen when patients undergo bilateral simultaneous TKA. Previous studies have often focused on increased serious cardiac complications among other issues in these patients. The present study notably identifies an increased risk of pulmonary complications as well as an association of higher complication rates with increasing patient age and a BMI greater than 30. There have been mixed reports in the literature about the association between BMI and complication rates following TKA and this study adds further data that should help us counsel these patients prior to surgery. It is also of great interest to see that the bilateral TKA patients had an increased length of stay in this study. Surgeons are being asked to more critically define standards of care and optimal care delivery and the data in this study offers important information that we must consider before offering patients bilateral procedures. The take-home message for me from this study is that complication rates appear to be higher when a simultaneous procedure is undertaken and that we are learning more and more about what patients appear to be at higher risk.

– Michael P. Bolognesi, MD
Assistant Professor Director of Adult Reconstruction Duke University Medical Center, Durham, N.C.

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