Comparison of Risk Factors for 1- and 2-Stage Revisions for Chronic Knee Periprosthetic Joint Infections

Background With the continued rise of total knee arthroplasties in the United States, chronic knee periprosthetic joint infections (PJIs) have become increasingly common. A 2-stage revision is considered the ‘gold standard’ first-line treatment, but a 1-stage revision has become an increasingly viable option. Many small-sample, single-institution studies have looked at how patient factors can affect the risk of failure of these first-line treatments. Few have looked at a large, multi-institutional cohort to determine the significant risk factors. Methods Patients who have chronic knee PJIs were identified in a deidentified records database. Failure after first-line treatment was defined as the need for further surgery, such as irrigation and debridement, rerevision, amputation, or arthrodesis, or the need for suppressive antibiotics. The 5-year risk of failure was evaluated for individual patient factors in order to identify variables for a multivariate Cox proportional hazards model. Overall risk for the individual measures of failure, as well as 90-day mortality, was also reported. Results Over 5 years after first-line treatment, 27.8% of 2-stage revisions failed and 40.4% of 1-stage revisions failed. Treatment failure was seen more commonly in patients who had prior methicillin-resistant Staphylococcus aureus infection, a body mass index greater than or equal to 30, or a previous diagnosis of depression. Those patients who underwent 2-stage revision surgeries first were more likely to fail with previous diagnoses of chronic kidney disease, lymphedema, or resistance to other antimicrobials. Those patients who underwent 1-stage revision surgeries were also more likely to fail if they had a previous diagnosis of malnutrition. Conclusions Orthopaedic surgeons should strongly consider patient comorbidities when selecting treatment pathways for PJIs.