Surgical washout and antimicrobial principles

The indication for surgical washout is an anatomical source that medication cannot reliably clear: purulent joint, abscess, necrotic fascia or muscle, infected devitalised bone, contaminated dead space or implant-associated biofilm requiring mechanical disruption. Define the target and urgency before theatre. A septic native joint differs from chronic fracture infection, and necrotising disease requires excision rather than lavage. Review imaging, implants, perfusion, stability and soft-tissue cover and involve plastic, vascular, spinal or arthroplasty expertise before an incomplete first operation commits future options.

Resuscitation and source control are parallel. Take blood cultures and correct immediately reversible physiological threats. A stable patient can remain off antibiotics until aspiration or operative samples are secured. A septic patient receives parenteral therapy after rapidly obtainable blood cultures, without waiting for the operating list. Record every prior antibiotic, allergy, organ dysfunction, anticoagulant and implanted device. Agree blood availability, tourniquet strategy, positioning, imaging and postoperative level of care with anaesthesia.

Plan samples before skin preparation. Aspirate fluid before incision or irrigation where feasible. In implant or fracture-related infection, take five deep microbiology samples from independent representative sites, each with a fresh sterile instrument and no-touch technique; take two histology specimens in chronic or uncertain infection. Label anatomy precisely rather than numbering unexplained pots. Notify microbiology of prior therapy, implants and suspected fastidious organisms. Superficial swabs, drain fluid and pooled tissues cannot substitute for disciplined deep sampling.

Exposure must reach the disease. Break loculations, irrigate all communicating spaces and remove pus, fibrin, foreign material and clearly non-viable tissue while preserving essential viable structures. Arthroscopy gives broad joint visualisation with less soft-tissue injury in many native large joints; open surgery may be necessary for advanced adhesions, inaccessible recesses, damaged tissue, bone involvement or failed arthroscopy. Necrotising infection requires systematic fascial and muscle assessment and radical debridement, not high-volume irrigation through a small portal.

Implant decisions depend on stability, union, biofilm maturity, symptom duration, organism and tissue. Retention may be reasonable only when fixation is essential and stable, debridement is sufficiently radical and effective antimicrobial treatment exists. Exchange accessible modular components during an indicated DAIR. Remove unnecessary or loose metalwork and restore fracture stability through a planned construct. Debride sequestrum and manage residual cavities with viable coverage; local antimicrobial carriers can support but never replace systemic therapy and perfusion.

At the end of surgery, record what was found, which tissues were excised, implant status, sample map, residual uncertainty, irrigation, drains, closure and planned re-look. Leave infected necrotising wounds open; other wounds close only when viable tissue and source control permit. A drain is not proof of clearance. Decide who will inspect the wound and when. Worsening physiology, recurrent effusion, persistent drainage or an unfavourable CRP and pain trajectory triggers immediate reconsideration of repeat exploration.

Empirical antibiotics start after samples unless instability required earlier administration. Use the full local source-specific regimen rather than a vague broad-spectrum label, and review at 48 hours as preliminary cultures emerge. Narrow to the pathogen and operation, document route and stop or review date, and involve infection specialists for prolonged or biofilm-active combinations. Oral therapy can be appropriate when highly bioavailable, active and absorbable; intravenous access is not itself evidence of superior source control.

Postoperative care protects the surgical result. Track observations, pain, perfusion, neurological status, wound, drains and blood-culture clearance. Adjust renal, hepatic and marrow monitoring to the chosen drugs and reconcile interactions. State weight-bearing and movement restrictions and begin rehabilitation early enough to prevent stiffness and deconditioning. Explain recurrence and toxicity signs. At discharge, make culture ownership explicit so late-growing organisms and susceptibility changes trigger action rather than disappearing after the patient leaves hospital.