- Design
- multicentre, open-label, randomised noninferiority trial with blinded endpoint adjudication (SOLARIO)
- Population
- 500 adults after surgery for orthopaedic infection with implantation of a local antibiotic carrier; 475 in the primary analysis
- Primary outcome
- definite treatment failure by 12 months
- Effect
- 14.1% (4 weeks or more) vs 11.1% (7 days or fewer); risk difference -3.0 percentage points (95% CI -9.0 to 3.0) against a 10-point margin; treatment-related symptoms by week 6, 45.2% vs 17.2%
SOLARIO randomised 500 adults who had undergone surgery for orthopaedic infection with implantation of a local antibiotic carrier to systemic antibiotics for at least four weeks or no more than seven days. Definite treatment failure at 12 months, adjudicated by a blinded endpoint committee, was 14.1% with the long course and 11.1% with the short one. Noninferiority was met.
The condition matters and should not be lost: this applies where antibiotic was delivered directly into the infected site at operation. It is not a general statement about bone and joint infection.
The harm figure is what makes this a practice-changer rather than a curiosity. By six weeks, symptoms potentially related to treatment had occurred in 45.2% of the long-course group against 17.2% of the short-course group. Four weeks of systemic antibiotics, often intravenous, often through a line, is a substantial intervention that has been treated as the cautious default. This quantifies what that caution costs, and shows it buys nothing measurable.
For an infection service the immediate action is a conversation with the orthopaedic team about which patients receive a local carrier, because that decision — made in theatre — now determines the length of the systemic course that follows.
- Ask at every orthopaedic infection referral whether a local antibiotic carrier was implanted
- Where one was, plan a seven-day systemic course from the outset rather than defaulting to four to six weeks
- Agree the pathway with the surgical team in advance; the theatre decision now drives the antibiotic plan
- Reassess the need for a long-line if the systemic course is a week — the line is a risk in its own right
- Record treatment-related symptoms at follow-up; nearly half the long-course patients had them by six weeks
The statistics, in plain English
The risk difference was -3.0 percentage points with a 95% confidence interval of -9.0 to 3.0, against a prespecified noninferiority margin of 10 percentage points — the entire interval sits inside the margin, so noninferiority is established. The interval crosses zero, so the apparent advantage of the short course is not itself proven superiority. Two sensitivity analyses in different populations gave consistent estimates, which matters because the trial was open-label; failure was adjudicated by a committee blinded to allocation, which is the safeguard that makes the primary outcome credible despite that.
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