New Orleans, LA—March 6, 2018
Acute kidney injury occurred in roughly 15 percent of patients receiving an antibiotic cement spacer during total knee arthroplasty (TKA) revision for periprosthetic joint infection (PJI). This news comes from a study presented at the annual meeting of the American Academy of Orthopedic Surgeons (abstract 5921). The study also demonstrated that anemia raised the risk of developing kidney injury, suggesting that clinicians should monitor anemic patients for kidney damage when implanting an antibiotic cement spacer.
"The key findings of this study are that acute kidney injury happens at a rate which is unexpectedly high and anemia is a predisposing factor," said Jose Rodriguez, MD, a study co-author and an orthopedic surgeon at Hospital for Special Surgery. "In this particular population that is at-risk, we may need to be more vigorous in monitoring for anemia and then treating with a transfusion earlier than we otherwise might have."
PJI is one of the most devastating and frequent complications that can occur after lower extremity joint arthroplasty, such as total knee replacement. The incidence of PJI varies by institution, from about .5 to 4 percent, and often requires revision surgery. Multiple procedures are sometimes necessary to eradicate infection and restore functionality, and even with successful eradication of infection, patients may not achieve optimal functional outcomes.
Mounting evidence suggests that treatment of PJI of the knee with an antibiotic cement spacer may increase the risk for acute kidney injury. "The concept for the study was that when we use a spacer for PJI, we are putting high concentrations of antibiotics in it, usually vancomycin which is renal toxic, in addition to sometimes treating these patients with intravenous vancomycin," said Dr. Rodriguez. "The question we wanted an answer to is what is the incidence of in-hospital acute kidney injury following treatment with an antibiotic spacer?"
To shed light on the issue, the researchers retrospectively identified 75 patients (39 male, 36 female) that received a static or articulating antibiotic cement spacer in New York City from 2007-2017. They collected and analyzed information on patient demographics, comorbidities, dose of antibiotic powder incorporated into the cement spacer, intravenous antibiotics administered, preoperative and postoperative creatinine, blood urea nitrogen and hemoglobin values. Acute kidney injury was defined as a more than 50 percent rise in serum creatinine from preoperative baseline to at least 1.4 mg/dL. A multivariate model was used to control for the demographics of age, gender, body mass index, and baseline creatinine.
The researchers found that in-hospital acute kidney infection occurred in 14.6 percent patients, at an average of 6.3 days (range, 2-8 days). A lower preoperative hemoglobin (OR=.55, P=.015) significantly increased the risk for infection on univariate analysis. Diagnosis of either hypertension or diabetes also showed a strong statistical trend for an increased risk of acute kidney infection (P=.056). When controlling for age (P=.0854), gender (female, P=.404), BMI (P=0.426), and baseline creatinine (P=0.340) on multivariate regression, lower preoperative hemoglobin significantly correlated with a greater percent rise in creatinine postoperatively (B=.304, P=.015).
Anemia is a well-known risk factor for postoperative AKI in patients undergoing cardiopulmonary bypass surgery, and the researchers believe that a lower baseline hemoglobin may be involved in the etiology of AKI in patients undergoing total knee revision. "The major risk factor was a lower hemoglobin level, so anemia predisposes patients to kidney injury, and these patients should receive closer monitoring," said Dr. Rodriguez.
The study was a collaboration among researchers at Lenox Hill Hospital, Monmouth Medical Center, Columbia University Medical Center, and HSS.
About HSS | Hospital for Special Surgery
HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the eighth consecutive year) and No. 3 in rheumatology by U.S. News & World Report (2017-2018). Founded in 1863, the Hospital has one of the lowest infection rates in the country and was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center four consecutive times. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State. In 2017 HSS provided care to 135,000 patients from 80 countries and performed more than 32,000 surgical procedures. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. The HSS Innovation Institute was formed in 2015 to realize the potential of new drugs, therapeutics and devices; the global standard total knee replacement was developed at HSS in 1969, and in 2017 HSS made 130 invention submissions (more than 2x the submissions in 2015). The HSS Education Institute provides continuing medical curriculum to more than 15,000 subscribing musculoskeletal healthcare professionals in 110 countries. Through HSS Global, the institution is collaborating with medical centers worldwide to advance the quality and value of care and to make world-class HSS care more accessible to more people.