Study Finds Small Increases in Complication Rates with Outpatient TKA

    Some complications are more common when total knee arthroplasty (TKA) is done as an outpatient or same-day procedure, according to a study recently published by The Journal of Bone & Joint Surgery.

    Using a US insurance database of patients who had a TKA procedure between 2007 and 2015, researchers from David Geffen School of Medicine at UCLA found higher rates of certain complications, including infections, repeat surgery, and blood clots, among patients undergoing outpatient TKA than among those undergoing inpatient surgery.

    The researchers compared rates of various complications over 1 year between a group of 4400 patients who underwent TKA and a group of 129,000 patients who underwent an inpatient TKA. Median age was similar between groups, but the outpatient group had fewer comorbidities.

    The most common complication – knee pain and stiffness requiring joint manipulation with the patient under anesthesia – occurred in 4.24% of patients undergoing outpatient TKA versus 3.57% of the inpatient TKA group. After adjustment for age, sex, and comorbidity, outpatient TKA patients had a relative 28% increase in the risk of this complication.

    Outpatient TKA was also associated with relative increases of 50% in surgical infections requiring irrigation and debridement, 22% in repeat surgery due to causes other than infection, and 35% in removal of the knee prosthesis. Absolute rates of these complications were low. For example, implant removal at 1 year occurred in 0.50% of outpatient TKAs versus 0.44% of inpatient TKAs.

    Two medical complications were also more frequent in the outpatient TKA group. The 60-day risk of deep vein thrombosis was 42% higher relative to inpatient TKA. There was also a small but significant 13% increase in the 14-day risk of acute kidney failure.

    There is growing interest in performing TKA as an outpatient procedure to avoid the costs associated with hospitalization for this common procedure. Although some studies have reported good outcomes, there are still limited data on the safety and effectiveness of outpatient TKA, which remains relatively uncommon.

    “The findings are particularly important to patients who may want to ask their surgeon whether or not they are medically optimal candidates for outpatient surgery and whether they will receive the standard antibiotic and thromboembolism prophylaxis protocols postoperatively,” said lead author Armin Arshi, MD.

    “We also recommend that they consider plans for physical therapy and rehabilitation after discharge, and in particular whether they will have adequate access to important rehabilitation at home during the important early postoperative period.”

    Senior author Nelson F. SooHoo, MD, said that, “[g]iven the low absolute rates of complications in both groups, it is likely that outpatient TKA will emerge as a safe option in the setting of postoperative care pathways that ensure equivalent attention to rehabilitation, antibiotic, and thromboprophylaxis as current inpatient protocols.”


    Arshi A, Leong NL, D’Oro A, et al: Outpatient total knee arthroplasty is associated with higher risk of perioperative complications. J Bone Joint Surg Am. 6 Dec 2017;99(23):1978-86. doi: 10.2106/JBJS.16.01332.