Open Fractures — BOAST Principles

Open fractures are orthopaedic emergencies defined by communication between the fracture haematoma and the external environment through a breach in the skin and soft tissues. They represent a spectrum from a small puncture wound overlying a closed fracture to a devastating degloving injury with complete soft tissue loss. The Gustilo-Anderson classification remains the universal language for describing open fracture severity and guiding management decisions. The British Orthopaedic Association Standards for Trauma (BOAST 4 for open fractures) define the contemporary care standards across the UK.

• BOAST 4 (British Orthopaedic Association Standards for Trauma — Open Fractures) defines the care standards for open fracture management in the UK; the core principle is that Gustilo IIIB and IIIC injuries (and other complex open fractures) should be managed at a Major Trauma Centre (MTC) with combined orthopaedic and plastic surgery expertise and facilities for free flap reconstruction, rather than at a Trauma Unit (TU) which does not have these resources; the transfer of complex open fractures to the MTC should not be delayed by definitive wound debridement at the TU — provisional wound management (saline-soaked dressing + wound photograph + splintage) should be performed and the patient transferred
• Wound assessment: clinical photograph of the wound should be taken BEFORE wound dressing is applied; this single photograph (ideally at the roadside or in the ED) allows subsequent assessment of wound size and contamination without repeated wound examination; the wound should NOT be repeatedly re-examined — every wound inspection is a risk for introduction of hospital-acquired organisms; `photograph once, dress and leave` — re-examine only in a clean operating environment
• Wound covering: wounds should be covered with a saline-soaked gauze and an impermeable film (sterile occlusive dressing) immediately after photography; this prevents desiccation of the wound and reduces environmental contamination; do NOT pack the wound with dry gauze or use betadine/chlorhexidine soaks directly into the wound (cytotoxic to tissues); the ideal covering is sterile saline-soaked non-adherent gauze covered with an occlusive film
• Antibiotics: intravenous antibiotics should be given at the earliest opportunity — ideally within 1 hour of injury; the BOAST 4 recommendation: co-amoxiclav (Augmentin) 1.2g IV for Gustilo I and II fractures; add gentamicin (5mg/kg IV once daily) for Gustilo IIIA, IIIB, IIIC injuries; metronidazole for highly contaminated wounds (farm/sewage/bowel contamination); UK BOAST recommendation aligns with the SIGN guideline; the LEAP study and EAST practice management guidelines confirm broad-spectrum antibiotics reduce infection rates; `antibiotics as soon as possible` is a key audit standard
• Tetanus prophylaxis: all open fracture patients require tetanus prophylaxis assessment; if immunisation status is unknown or incomplete — tetanus immunoglobulin (TIG) + tetanus toxoid; if fully immunised (within 10 years) — tetanus toxoid booster if last dose >5 years ago; contaminated wounds require TIG regardless of immunisation status if any doubt
• Timing of debridement: the historical `6-hour rule` (debridement mandatory within 6 hours) has been challenged and is NOT supported by Level 1 evidence; modern BOAST guidance: Gustilo I and II — debridement within 12–24 hours at the MTC/TU; Gustilo III — debridement as soon as possible (within 24 hours), ideally at the MTC, by a combined orthopaedic and plastic surgery team; the quality of debridement and the facilities at the treating centre are more important than the absolute time to debridement; `right place rather than right time` is the current principle for complex injuries
• Fix and flap principle: for Gustilo IIIB fractures, definitive skeletal fixation AND soft tissue coverage should be performed within 72 hours — the `fix and flap within 72 hours` principle; soft tissue coverage (free flap, local flap, or split skin graft as appropriate) within 72 hours is associated with significantly lower infection rates than delayed coverage; delay beyond 5–7 days dramatically increases infection risk; the `fix and flap` should be performed as a single combined operation at the MTC by orthopaedic and plastic surgeons simultaneously (not sequentially); the `fix and flap` concept is the single most important management principle for Gustilo IIIB fractures

• Radical debridement: all contaminated, devitalised, and necrotic tissue must be excised; tissue viability assessment uses the `4 Cs` — Colour, Contractility, Consistency, Capacity to bleed; all four must be present to consider tissue viable; fat necrosis should be excised aggressively (fat is a poor host for infection); muscle viability is the most difficult to assess and the most critical — pink, bleeding, contracting muscle = viable; grey, non-contracting, non-bleeding = non-viable and must be excised; `when in doubt — take it out`
• Wound extension: the skin wound is extended proximally and distally to allow adequate exploration of the zone of injury; decompression of compartments (fasciotomy) should be performed at the same time if compartment syndrome is suspected or likely
• Irrigation: high-volume saline irrigation after debridement; 6–9 litres of normal saline for Gustilo III injuries; the FLOW trial (Bhandari et al.) demonstrated no difference between high-pressure and low-pressure irrigation and no benefit of adding soap or antiseptic to saline; simple low-pressure irrigation with normal saline is the evidence-based recommendation; high-pressure pulsatile lavage may drive bacteria deeper into bone and is NOT recommended
• Negative pressure wound therapy (NPWT/VAC): after debridement, temporary wound management with NPWT (wound VAC) maintains a moist wound environment, reduces bacterial burden, promotes granulation, reduces oedema, and bridges the time to definitive soft tissue coverage; the standard temporary wound closure between the debridement and the plastic surgery flap procedure; NPWT should NOT be used as a substitute for adequate debridement or to delay definitive coverage indefinitely; NPWT is applied at the time of debridement and the wound is re-assessed at 48–72 hours for definitive coverage

• Gustilo-Anderson: I (<1 cm, clean, <2% infection); II (1–10 cm, moderate, 2–5%); IIIA (adequate cover possible, 7–10%); IIIB (exposed bone, flap required, 10–50%); IIIC (vascular injury, 25–50%, highest amputation rate); vascular injury = IIIC regardless of wound size
• BOAST 4 key principles: photograph wound immediately (once, then cover); saline-soaked non-adherent dressing + occlusive film (NOT betadine/dry gauze); IV antibiotics within 1 hour; Gustilo III → MTC with combined ortho + plastics team
• Antibiotics: co-amoxiclav (1.2g IV) for Gustilo I/II; add gentamicin (5mg/kg) for Gustilo III; add metronidazole for farm/bowel/sewage contamination; within 1 hour of injury
• Fix and flap within 72 hours: Gustilo IIIB standard; definitive skeletal fixation + soft tissue coverage within 72 hours reduces infection dramatically; combined ortho + plastic surgery operating simultaneously; NPWT bridges the time between debridement and flap
• `Right place rather than right time`: for complex Gustilo III fractures, transfer to MTC with expertise is more important than emergency debridement at a TU without plastics; do NOT delay transfer for definitive debridement at TU; photograph, dress, stabilise, and transfer
• Debridement 4 Cs: Colour, Contractility, Consistency, Capacity to bleed — ALL four required for tissue viability; `when in doubt — take it out`; high-volume saline irrigation (6–9 L for Gustilo III); FLOW trial — simple low-pressure saline irrigation = evidence-based; high-pressure pulsatile lavage NOT recommended
• Vascular injury (IIIC): sequence = skeletal stabilisation (ExFix) FIRST → temporary intravascular shunt → then definitive vascular repair; ExFix before vascular repair prevents disruption of the anastomosis during fracture manipulation; time to revascularisation <6 hours from injury to limit ischaemia
• IMN vs ExFix for open tibia: IMN superior (SPRINT trial and meta-analyses); lower re-operation, malunion, infection rates; unreamed IMN for Gustilo III to preserve endosteal blood supply; convert ExFix to IMN within 2 weeks before pin-site infection develops