Extended Antibiotic Prophylaxis Can Reduce PJIs in Revision TKA Patients
In a study published at the end of last year, R. Michael Meneghini, MD, and his colleagues from the Indiana University School of Medicine reported that high-risk primary total knee arthroplasty (TKA) patients who took antibiotics for 7 days after surgery were nearly 5 times less likely to develop a periprosthetic joint infection (PJI) than patients who did not take antibiotics postoperatively. 
They concluded that this protocol of extended antibiotic prophylaxis resulted in a “statistically significant and clinically meaningful reduction in the 90-day infection rate of selected patients at high risk for infection.”
They also wondered: Would the same be true of revision TKA patients?
Little is known about the duration and effects of extended antibiotic prophylaxis in revision TKA patients, who are at much higher risk of PJI than primary TKA patients: The PJI rate after revision procedures has been reported as high as 7%.
Dr. Meneghini and his colleagues hypothesized that with extended antibiotic prophylaxis, revision TKA patients would have outcomes similar to those of the primary TKA patients in their published study. Anecdotally, they had observed positive outcomes with this protocol in revision TKA patients, Dr. Meneghini said.
To test this hypothesis, they retrospectively reviewed the records of 180 consecutive patients who underwent aseptic revision TKA at their institution between 2013 and 2017. The majority of these patients – 77% – had serious comorbidities, as indicated by their ASA III and IV status.
The operating surgeons had obtained intraoperative cultures on all patients and ordered intravenous (IV) antibiotics while the patients were in the hospital. At discharge, all patients received a prescription for 7 days of oral antibiotic prophylaxis, the time it would take for the cultures to incubate.
For the extended antibiotic prophylaxis, “We initially used cephalexin (Keflex), 500 mg PO 4 times daily, but then a couple years ago transitioned to a twice-a-day cephalosporin, cefadroxil,” Dr. Meneghini said. “If patients had a true allergy to penicillin, then we would use Clindamycin. If the patients were screened positive for MRSA colonization, we would use sulfamethoxazole and trimethoprim (Bactrim).”
Additional prophylactic measures Dr. Meneghini and his colleagues take perioperatively to prevent infection in revision TKA patients include:
- Nasal colonization screening
- Dilute povidone-iodine lavage prior to closure
- Wound closure with a monofilament running suture and a skin glue sealant
- Silver iodine occlusive dressing left in place for 7 days after surgery
For the study, Dr. Meneghini and his colleagues reviewed culture results and documented complications, reoperations, and infections for this patient cohort. At the 2019 Annual Meeting of the American Academy of Orthopaedic Surgeons, they reported a 90-day PJI rate of 0.5%, which they described as “a clinically meaningful four-fold decrease in PJI in this challenging cohort of patients with substantial medical comorbidities” compared with reported PJI rates in revision TKA patients.
Most patients had either negative intraoperative cultures or an isolated positive culture that was considered to be a contaminant and not a true infectious organism. Only 1 patient had 2 or more positive cultures and subsequently underwent a 6-week course of IV antibiotics. Three patients had reoperations for deep infection.
Dr. Meneghini said that he and his colleagues “feel [extended antibiotic prophylaxis] is a very practical and evidence-based way to prevent infection in revision TKA patients, who are considered at higher risk than primary” TKA patients.
But they also encourage further study of this protocol in primary and revision TKA patient and caution that the benefits of extended antibiotic prophylaxis should be “appropriately weighed” against any potential for resulting antibiotic resistance.
Zingg M, Ziemba-Davis M, Meneghini RM. Reduced Infection Rate After Contemporary Revision Total Knee Arthroplasty with Extended Antibiotic Protocol (Paper 004). Presented at the 2019 Annual Meeting of the American Academy of Orthopaedic Surgeons, March 12-16, Las Vegas, Nevada.
- Inabathula A, Dilley JE, Ziemba-Davis M, et al. Extended oral antibiotic prophylaxis in high-risk patients substantially reduces primary total hip and knee arthroplasty 90-day infection rate. J Bone Joint Surg Am. 2018 Dec 19;100(24):2103-2109. doi: 10.2106/JBJS.17.01485.