Osteomyelitis — Surgical Debridement and Dead-Space Management

Indication. Radical surgical debridement combined with targeted antibiotics is the cornerstone of treatment for chronic osteomyelitis. The clearest indications are chronic infection with a sequestrum or necrotic bone on imaging (Cierny-Mader Type III or IV), a septic nonunion with a mobile fracture site and a persistent sinus or drainage, recurrence after a previous debridement, and a pathological fracture through osteomyelitic bone. Cierny-Mader Type II superficial disease that has failed local wound care, and Type I medullary disease persisting after reaming and antibiotics, are relative indications. Absolute contraindications. A C-host in whom surgical morbidity exceeds the benefit of surgery (consider lifelong suppression or amputation instead), and active untreated systemic sepsis that requires immediate source control elsewhere. Relative contraindication. A B-host with unoptimised comorbidities — smoking, glycaemic control, nutrition, vascular disease — who must be optimised before any major reconstruction; and a small contained Type I lesion that may be manageable on long-term oral antibiotics alone. Pre-operative work-up:

• History: duration of drainage, previous surgeries and antibiotic courses, smoking, diabetes, vascular symptoms.
• Laboratory: CRP, ESR, white cell count, albumin, HbA1c; blood cultures if there are systemic signs.
• Imaging: plain radiographs (sinus tracts, sequestrum, involucrum), MRI (extent of marrow and soft-tissue involvement), CT (cortical detail and sequestrum mapping), angiography if a flap is planned.
• Microbiology: deep bone biopsy or sinus-tract culture if available; hold antibiotics until the samples are obtained.
• Host optimisation: smoking cessation (minimum 4–6 weeks), glycaemic control (HbA1c less than 8 percent), nutritional support (albumin greater than 3.5 g/dL), vascular assessment and revascularisation if indicated.

Consent. Discuss the risk of recurrence (10–30 percent depending on host and extent), amputation, flap failure, nonunion, pathological fracture, prolonged antibiotics, and multiple staged procedures. Setup. Supine on a radiolucent table with the limb prepped free; a tourniquet is optional and used only for the initial exposure if bleeding obscures the view, with a bump under the ipsilateral hip for the lower limb. General or regional anaesthesia; avoid local infiltration until the cultures are obtained.

The goal is to remove every last piece of necrotic, infected bone and biofilm while preserving living tissue and stability, then manage the resulting dead space and soft-tissue defect so the limb can be reconstructed. The exposure — an extensile approach that incorporates every sinus tract — is the foundation: if you cannot see all of the disease, you cannot resect it.

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Local antibiotic carriers maintain the dead space, deliver very high local antibiotic concentrations, and — for PMMA — induce a membrane for later grafting:

Post-operative antimicrobial therapy - Duration: typically 6 weeks of pathogen-specific intravenous antibiotics followed by 2–6 months of oral suppression, guided by infectious diseases and microbiology.

• Route: intravenous initially for severe or resistant organisms, with an early switch to oral when the clinical response and oral bioavailability allow.
• Monitoring: weekly CRP, renal function (for aminoglycosides/vancomycin), and drug levels as indicated.
• Multidisciplinary input: a mandatory infectious-disease consultation for complex or resistant infections. Rehabilitation | Phase | Timing | Weight-bearing & activity | Monitoring & milestones | |------|--------|---------------------------|--------------------------| | Early | 0–6 weeks | Maintain external fixation or cast; non-weight-bearing or touch weight-bearing until soft-tissue healing; gentle ROM of adjacent joints, isometrics | Daily pin-site care; watch for pin-site infection | | Intermediate | 6–12 weeks | Progressive weight-bearing as transport or graft incorporates; transition to a removable brace once stability allows | Remove PMMA spacer/beads at 6–8 weeks if Masquelet planned and graft at the same sitting | | Late | 3–12 months | Full weight-bearing once radiographic union is confirmed; strengthening, gait training, proprioception | Surveillance imaging and CRP every 3 months for the first year, then annually | | Return to function | — | Sedentary work 3–6 months; manual labour 6–12 months or longer with transport; high-impact sport individualised, often permanently restricted | Individualised counselling | Complications

Pathoanatomy. In chronic osteomyelitis a segment of devitalised cortex — the sequestrum — separates and is surrounded by reactive, living new bone, the involucrum. Pus under pressure tracks to the skin surface, forming a sinus tract. Because the sequestrum is avascular it cannot be reached by host defences or antibiotics, so it persists as a permanent nidus for infection until it is excised; a sinus tract present for decades carries a small but classic risk of malignant transformation to squamous-cell carcinoma (Marjolin's ulcer), which is why every long-standing sinus is biopsied at debridement. Cierny-Mader classification. The anatomic type describes where the disease sits and therefore how much bone must be removed; the physiologic host class describes the patient's capacity to heal and therefore whether aggressive reconstruction is justified. Together they set the resection volume, the reconstruction plan, and the perioperative optimisation.

Physiologic host classes:

• A-host — normal immune and vascular status; the best candidate for aggressive reconstruction.
• B-host — compromised locally (smoking, vascular disease, radiation) or systemically (diabetes, malnutrition, immunosuppression); requires optimisation before definitive surgery.
• C-host — the treatment risk is greater than the disease burden; consider suppression or amputation. Evidence base. Radical surgical debridement combined with targeted antibiotics remains the cornerstone of treatment for chronic osteomyelitis, and the Cierny-Mader classification guides both the extent of resection and the need for reconstruction. Modern series show that adequate resection to bleeding bone plus local antibiotic delivery and stability achieves infection-free union in 70–90 percent of cases when host factors are addressed, although exact rates vary by anatomic site and host class. The induced-membrane (Masquelet) and bone-transport (Ilizarov/Paley) techniques extended what is reconstructable after radical debridement, making limb salvage realistic even for large segmental defects.