Local antibiotic delivery using bone graft as the carrier has shown promise against prosthetic joint infection, but the evidence has been small and mostly uncontrolled. An international, randomised, double-blind, placebo-controlled trial will randomise 1100 patients undergoing total hip arthroplasty who require bone grafting, 1:1, to graft impregnated with tobramycin and vancomycin or to placebo-impregnated graft. Revisions for ongoing infection are excluded.
The primary outcome is time to reoperation for infection or diagnosis of prosthetic joint infection, and the investigators have prespecified that a risk reduction of at least 50% would be clinically relevant - a useful discipline, since it commits them to a threshold before seeing the data. Secondary outcomes run to five years and include the organisms isolated and their susceptibility patterns, which is the part infection specialists should watch.
That susceptibility endpoint is the real question. Local high-concentration aminoglycoside and glycopeptide exposure around an implant is a selection pressure, and a strategy that reduces infection rates while shifting the organisms that do occur towards resistance is not straightforwardly a win. This is a protocol: no results, nothing to change today.
- No results yet - this is a published protocol for a trial in recruitment.
- Watch the five-year susceptibility endpoint as closely as the infection rate.
- Note the prespecified 50% risk reduction threshold when the results appear.
- Local delivery does not remove the need for systemic prophylaxis according to local protocol.
- Aseptic loosening is a declared safety outcome: impregnated graft could affect incorporation.
Why it matters
It will be the first adequately powered test of whether local antibiotic delivery in arthroplasty buys infection reduction at an acceptable resistance cost.
Don't overread it
This is a protocol paper: no patients have been reported, and the intervention has not been shown to work.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for infectious diseases, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free