Necrotizing fasciitis

Necrotizing fasciitis is a rapidly progressive, life-threatening infection originating in a fascial plane which requires emergency surgery. Although uncommon, with an incidence of 0.63 per 100,000 per year, it affects the limbs in 40% of cases and carries a 22% 30-day mortality rate. The diagnosis is principally clinical. Severe pain, out of proportion to any visible abnormality of the skin, is the cardinal early feature, frequently accompanied by tenderness beyond the area of erythema, swelling, and local hypoaesthesia. Crucially, the skin may initially appear normal or nearly normal while rapid fascial destruction progresses beneath. Laboratory investigations, imaging, and scoring systems lack sufficient sensitivity and specificity to confirm or exclude the diagnosis and must not delay surgical exploration. The suspected diagnosis is confirmed or excluded by a diagnostic incision to the fascial plane. Necrotizing fasciitis is classified into four types based on the microbiology: polymicrobial (type I), Gram-positive monomicrobial (type II), Gram-negative monomicrobial (type III), and fungal (type IV). The focus of treatment is emergency radical excision of all necrotic tissue to healthy margins and broad-spectrum antibiotics. Surgery should not be delayed by medical management, imaging, or inter-hospital transfer. Failure to recognize and act within six hours of presentation is associated with a five-fold increased risk of mortality and amputation, while survivors of delayed surgery report health-related quality of life comparable to death. Postoperative review within six hours is mandatory. This annotation complements the publication of the British Orthopaedic Association Standards on musculoskeletal infections, and provides recommendations for orthopaedic surgeons managing patients with necrotizing fasciitis.