Failure Factors after 1-Stage Exchange TKA
Prior to performing a primary total joint arthroplasty, patient optimization is both possible and recommended. However, when a patient with a periprosthetic joint infection (PJI) comes in to your office, opportunities for patient optimization are limited. At that point, the patient’s BMI, kidney/liver values, and HgbA1c/fructosamine levels are not going to be dramatically improved prior to any procedure to eradicate the infection and/or salvage the implant. Still, for the purposes of care optimization and prognostic guidance, it is important to identify specific patient or wound characteristics that may help us flag patients who are at increased risk for failure after treatment of a PJI.
That was the goal of the case-control study by Citak et al. in the June 19, 2019 edition of The Journal. The authors compared 91 patients who experienced a failed 1-stage revision total knee arthroplasty that was performed to treat a PJI to a matched cohort who had a successful 1-stage revision to treat a PJI. (The authors defined “failure” as any subsequent surgical procedure regardless of reason.)
A bivariate logistic analysis revealed that patients who had a history of a previous 1-stage (OR 29.3; p< 0.001) or 2-stage (OR 5.8; p <0.001) exchange due to PJI, or who had Streptococcus (OR 6.0; p = 0.013) or Enterococcus (OR 17.3; p = 0.023) isolated from their wound were at increased risk of reinfection compared to the control group. Just as important, the authors found that patient body weight of 100 kg or above and history of deep vein thrombosis (DVT) were the only patient comorbidities related to an increased risk of a failed revision.
While these findings may not be surprising in light of previous data on this topic, they are important in aggregate. Patients whose wounds contain isolated enterococci or streptococci may not be ideal candidates for 1-stage PJI revision surgery. Additionally, the authors highlight that patients who have failed two or more attempts at a 1-stage revision should be considered for a 2-stage protocol.
While many of the patients in this study who failed the 1-stage revision may have also failed a 2-stage revision, ongoing research comparing the two protocols should help further clarify whether certain infections are more amenable to successful treatment with one protocol or the other. In the meantime, studies such as this add valuable data that surgeons can use to guide patient care and provide meaningful patient education for shared decision-making about how to treat these difficult infections.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media