How a 7-Day Pill Protocol Reduces Revision TKA Infections by Up to 4x

Unpacking the microbiology and clinical outcomes of prescribing cephalexin or cefadroxil after aseptic knee revisions.

The demand for primary total knee arthroplasty (TKA) is projected to increase, with an associated estimated parallel increase in the number of aseptic revision TKAs. Revision surgery is a well-described risk factor for periprosthetic joint infection (PJI), due in part to longer operative time and re-exposure of deep structures with poorer vascularity and scarring to potential bacterial contamination, in addition to being more prevalent in older, more immunocompromised hosts. In the United States, PJI after aseptic R-TKA occurs in 3%-7.5% of cases, up to a magnitude greater than the 0.7%-1.5% rate associated with primary TKA.

Historically, extended antibiotic therapy after total joint arthroplasty (TJA) surgery was used to mitigate initially high infection rates. However, 2017 guidance from the Centers for Disease Control and Prevention recommended against antibiotic administration after arthrotomy closure, as did the World Health Organization in 2018. Two orthopedic professional associations disagreed with the Centers for Disease Control and Prevention’s recommendation because current practice has held primary TJA infection to <1%, and there is limited evidence to support the recommended change. We set out to see what the data actually says when standard protocols are extended for this high-risk population.