Periprosthetic Joint Infection — Debridement, Antibiotics and Implant Retention (DAIR)

What DAIR is. Debridement, Antibiotics and Implant Retention is a single-stage salvage operation for an acute periprosthetic joint infection in which the implant is still well fixed. It buys implant retention by surgically removing the planktonic and early-biofilm burden, exchanging the modular parts that harbour biofilm, and then suppressing residual organisms with targeted biofilm-active antibiotics. Done well, on the right patient, it avoids the morbidity of a two-stage revision; done on the wrong patient it simply delays it and burns the chance of retention. The indication, in one sentence. An acute PJI — either acute post-operative (symptom onset less than 3 weeks after the index arthroplasty) or acute haematogenous (symptoms less than 3 to 4 weeks) — in a patient with a well-fixed implant, a susceptible organism, an intact soft-tissue envelope, and no sinus tract. Absolute indications (all should be present):

• Acute post-operative PJI with symptom onset less than 3 weeks after the index arthroplasty.
• Acute haematogenous PJI with symptom duration less than 3 to 4 weeks.
• Well-fixed implant on preoperative radiographs and confirmed stable intraoperatively.
• Susceptible organism on preoperative aspiration or Gram stain (streptococcus, coagulase-negative staphylococcus, or a known sensitive organism).
• Intact soft-tissue envelope without a sinus tract or severe scarring. Relative indications — early post-operative PJI (less than 6 weeks from the index) with borderline symptom duration but a favourable organism and host; a patient with significant medical comorbidity in whom two-stage revision carries prohibitive risk; or a single early debridement performed elsewhere with a retained implant, now referred for definitive management. Who should NOT have a DAIR — the contraindications that push the decision to a two-stage revision:

Consent. Counsel the patient that even with optimal selection and technique DAIR fails in roughly 25 to 45 percent of cases and that a two-stage revision may still be required; that prolonged intravenous and oral antibiotics carry renal, hepatic, gastrointestinal and neurological side effects; that the operated joint may be stiffer; and (for the hip) that dislocation risk after a posterior-approach DAIR is higher than after a primary.

The goal is a radical, open debridement of the entire joint through the index approach, exchange of every modular part that can harbour biofilm, copious irrigation, confirmation that the implant is solid, and primary wound closure — all cultures taken before a single dose of antibiotic is given. The exposure is laid out in full below (and in depth on the posterior approach to the hip and medial parapatellar approach to the knee pages).

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Immediate post-operative protocol (day 0 to 3). Intravenous antibiotics commence after the final culture is obtained in theatre — the initial regimen is vancomycin plus a third-generation cephalosporin or piperacillin-tazobactam, pending culture results. A drain, if used, is removed at 24 to 48 hours. Mobilise with full weight-bearing as tolerated from day 1 (knee) or day 2 (hip). Review the wound at 48 hours and apply a negative-pressure dressing if drainage persists. Week 1 to 6. Tailor antibiotics to the culture results once available (usually at 48 to 72 hours). Add biofilm-active agents: rifampicin 300 mg twice daily for staphylococci (after confirming susceptibility and once the wound is dry); ciprofloxacin or levofloxacin for Gram-negative organisms. Total intravenous duration is 6 weeks, followed by an oral step-down for 3 to 6 months (or indefinite suppression in selected high-risk cases). Weekly wound review; CRP and ESR at 2, 4 and 6 weeks. Month 3 to 6. Continue oral antibiotics until the CRP normalises and remains normal for 4 weeks off therapy (in patients planned for a finite course). Clinical and radiographic review at 3 and 6 months. If infection recurs, proceed to two-stage revision.

Surveillance. CRP and ESR at 2, 4 and 6 weeks, then at 3, 6 and 12 months, then annually to 5 years — late recurrence is possible. Any rise in markers or return of symptoms prompts repeat aspiration and consideration of two-stage revision. Weight-bearing is as tolerated from day 1 to 2, with no routine bracing.

Epidemiology and success rates. Contemporary series report overall DAIR success — implant retention without further surgery for infection — of 55 to 75 percent at 2 years when strict selection criteria are applied, with success highly dependent on timing, organism and the presence of a sinus tract. A systematic review of 39 studies (928 knees, 677 hips) found pooled success of 67 percent when DAIR was performed within 3 weeks of symptom onset versus 42 percent when performed later; staphylococcal infections (especially MRSA) and sinus tracts were independent predictors of failure on multivariate analysis. Biofilm-relevant anatomy. Periprosthetic biofilm forms preferentially at the bone-implant interface, the modular taper junctions and the polyethylene surface. The posterior recesses of both hip and knee are the most common sites of residual infection after an inadequate DAIR because they cannot be visualised or debrided without removing the modular components — the anatomical basis for the mandatory modular exchange. Classification systems that drive decision-making. Two staging systems stratify risk and frame the DAIR-versus-revision decision:

McPherson staging combines a host grade (A uncompromised, B compromised, C significantly compromised — for example immunocompromised, dialysis, active malignancy) with a local extremity grade (1 uncompromised, 2 compromised, 3 severe — multiple previous incisions, radiation, severe scarring). A McPherson C host with a grade 3 extremity has a DAIR failure rate exceeding 70 percent, which is why most surgeons proceed directly to two-stage revision in that setting.