Patients undergoing bilateral total knee arthroplasty (TKA) are at an increased risk of several sorts of complications, as compared with matched patients undergoing unilateral TKA, reports a study in The Journal of Bone & Joint Surgery. The journal is published within the Lippincott portfolio in partnership with Wolters Kluwer.

“Patients who underwent simultaneous bilateral TKA were at higher risk of experiencing postoperative complications akin to pulmonary embolism, stroke, blood loss anemia, and requiring a transfusion,” in line with the report by Nathanael D. Heckmann, MD, and colleagues of Keck School of Medicine of USC, Los Angeles.

Study in matched groups of patients clarifies risks of bilateral TKA

TKA is a highly effective treatment for patients with advanced osteoarthritis of the knee, decreasing pain and improving function. When each knees are affected, bilateral TKA offers some benefits over sequential unilateral TKA, including less time within the hospital, a single rehabilitation period, and lower overall costs.

Nevertheless, some studies have found an increased risk of complications, together with a better mortality rate, in patients undergoing bilateral TKA. These studies have had vital limitations, including an absence of patient matching to account for potential differences between those undergoing bilateral versus unilateral TKA. To handle these issues, Dr. Heckmann and colleagues compared complications and mortality in a big, nationally representative group of patients undergoing bilateral versus unilateral TKA.

The evaluation included greater than 21,000 patients undergoing simultaneous bilateral TKA. These were matched for age, sex, race, and comorbidities with a cohort of 126,000 patients undergoing unilateral TKA. After matching, the 2 groups had a mean age of 64 years with similar comorbidities. As all TKAS were performed between 2015 and 2020, the surgical procedures reflected modern orthopaedic practice.

Stroke, transfusion, and other risks higher following bilateral TKA

Patients within the simultaneous bilateral TKA group had increased rates of several sorts of complications compared with those within the unilateral TKA group, pulmonary embolism (0.27% versus 0.13%), stroke (0.13% versus 0.06%), and respiratory failure (0.46% versus 0.34%).

Patients undergoing bilateral TKA were also at a better risk of anemia as a result of blood loss (26.89% versus 14.86%) and were more more likely to undergo a blood transfusion (5.23% versus 0.67%). These risks were increased despite the high use of tranexamic acid to scale back blood loss during surgery in each groups.

Patients undergoing bilateral TKA were also more more likely to be readmitted to the hospital inside 90 days (2.80% versus 2.05%). There was no significant increase in the chance of in-hospital death (0.05% versus 0.04%).

After adjusting for confounders, the risks of pulmonary embolism, stroke, and acute blood loss anemia were roughly doubled within the bilateral TKA group, while the chance of blood transfusion was nearly nine times higher. The danger of readmission inside 90 days was 35% higher with bilateral compared with unilateral TKA.

“This study presents the most important matched sample size thus far comparing the complications and safety between patients treated with simultaneous bilateral TKA and people treated with unilateral TKA,” Dr. Heckmann and coauthors write. Although there was no significant difference in the speed of in-hospital death, “The danger of mortality following simultaneous bilateral TKA remains to be a subject of concern.” The researchers emphasize the necessity for patient counseling and “thorough medical optimization” in patients chosen for bilateral TKA.