Osteomyelitis (Campbell's Operative Orthopaedics, 15th Ed.)

Classification

• Exogenous - from open fractures, surgery (iatrogenic), or contiguous spread from infected local soft tissue
• Hematogenous - results from bacteremia seeding bone

Acute Hematogenous Osteomyelitis

• The most common type of bone infection, seen mainly in children
• Bacteremia is the cause; seeding is favored by localized trauma, chronic illness, malnutrition, or an inadequate immune system - though often no source is identified
• In children, infection typically starts in the metaphysis of rapidly growing long bones. Bacterial seeding triggers an inflammatory reaction causing local ischemic necrosis and abscess formation. As intramedullary pressure rises, cortical ischemia develops and pus can escape through the cortex into the subperiosteal space, forming a subperiosteal abscess
• Age distribution is bimodal: children younger than 2 years, and children 8-12 years old
• S. aureus is the most commonly isolated organism across sites (also true for hand osteomyelitis specifically)
• Diagnosis relies on clinical exam plus imaging (radiographs, radionuclide scans - technetium, gallium, or indium-labeled leukocyte scans; MRI is favored for detecting sinus tracts, extent of infection, and bone-vs-soft-tissue differentiation)
• Treatment principles: prompt IV antibiotics, needle aspiration for culture when possible, and surgical drainage/debridement if no organism is obtained or if pus/necrotic material is present, plus early mobilization

Subacute Hematogenous Osteomyelitis / Brodie Abscess

• A more indolent presentation than acute disease; can present as a localized, walled-off intraosseous abscess (Brodie abscess)
• Subacute and even chronic disease can radiographically and clinically mimic bone tumors - Campbell's specifically warns about misdiagnosis as Ewing sarcoma, osteogenic sarcoma, osteoid osteoma, or eosinophilic granuloma (and occasionally multiple myeloma, if plasma cell response is prominent). Any biopsy of a suspected musculoskeletal neoplasm should routinely be sent for culture as well as histology

Chronic Osteomyelitis

Cierny-Mader Classification

• Anatomic type (4 types, based on location/aggressiveness of the lesion - e.g., medullary, superficial, localized, diffuse)
• Physiologic class - host status: A (normal host), B (locally or systemically compromised host), C (treatment worse than the disease - minimal disability, prohibitive morbidity anticipated, or poor prognosis for cure)

Treatment

• Acute/subacute disease without sequestrum may resolve with antibiotics alone (guided by aspiration culture) without surgery
• Once sequestra form (chronic infection), management includes debridement/sequestrectomy, diaphysectomy (in digits), external fixation, antibiotic-impregnated PMMA (polymethylmethacrylate) beads/spacers, and subsequent bone grafting
• Malignant transformation (squamous cell carcinoma, fibrosarcoma) can rarely occur in chronically draining osteomyelitic sinus tracts of long duration

Site-Specific Notes from Campbell's

• Hip/proximal femur: If septic arthritis of the hip is drained promptly with appropriate antibiotics, osteomyelitis of the proximal femur is usually prevented. In children under 12, osteomyelitis causing sequestration of the femoral head may lead to complete reabsorption or replacement by new bone once circulation is restored; in older children/adults, the sequestrum typically persists and needs excision. This can also lead to pathologic femoral neck fracture and pelvic (iliopsoas) abscess formation, which may require CT-guided or open drainage.
• Hand/digits: Can result from infected neighboring soft tissue, open fractures, open treatment of closed fractures, or systemic conditions (PVD, diabetes, immunodeficiency). Hematogenous spread to the hand is rare and mainly seen in immunocompromised patients. S. aureus predominates. MRI is the preferred initial advanced imaging modality; CT helps identify sequestra in chronic disease. Severe stiffness often limits digit salvage, and amputation (at the joint proximal to the involved bone) may be necessary if function can't be preserved.

Recent Evidence Check

• A 2025 systematic review supports oral amoxicillin/clavulanate as an effective option in osteomyelitis treatment (PMID: 41569452), relevant to the antibiotic-therapy discussion above.
• A 2025 systematic review on hand osteomyelitis specifically reinforces Campbell's points on debridement and amputation thresholds (PMID: 39462293).