Chronic osteomyelitis is persistent bone infection with dead bone (sequestrum), often after trauma, surgery or inadequately treated acute infection. It is staged with the Cierny-Mader system, and cure usually needs thorough debridement, dead space management, stabilisation, soft tissue cover and targeted antibiotics.

Definition

• Osteomyelitis following
  • Inadequately treated acute osteomyelitis
  • Post-traumatic
  • Post-surgical treatment
• Chronic haematogenous form – 30% of all chronic osteomyelitis

Histological Definition

• Infection of bone corresponding with development of necrotic bone

Chronological Definition

• Osteomyelitis persisting after 6 months (variable time used in literature)
• Osteomyelitis with radiologic evidence of sequestra, involucrum, radiolucency, & clinical evidence of sinus or fistula

Aetiology

• Often improperly treated conditions
• Pertinent factors predisposing to it include
  • Degree of bone necrosis
  • Nutritional status of involved tissues
  • Nature of infecting organisms
• Risk factors
  • Old
  • Debilitated
  • IV drug users
• Organisms involved are most commonly
  • S Aureus & Gram neg rods
  • May see
    • Pseudomonas
    • Enterobacter
    • E coli
    • Polymicrobial in > 30%
  • Pure Staph ~ 25%
  • Note increasing incidence of G- rods over past 20 years

Pathogenesis

• Initial metaphyseal abscess or direct inoculation
• Resolves with appropriate treatment
• Contained by host defences & persists as subacute or chronic localised infection
• Spreads to involve adjacent structures
• Medullary canal fills with pus & pressure forces infection through Haversian canals to the periosteum to form subperiosteal abscess
• The hole in the cortex is the cloaca
• Periosteum lifts & may form new bone resulting in an involucrum
• Vascular obstruction with thrombosis may result from many factors
  • Pressure
  • Leucocytic enzymes & acidic pH
  • Periosteal stripping
• Results in segment of dead bone called the sequestrum
• In the adult the periosteum is adherent to the cortex so pus tends to break through to form multiple soft tissue abscesses
• overlying skin is affected in chronic conditions
  • Indurated, puckered & adherent to bone
  • Sinus often connects the skin with bony lesion
• histological picture is one of chronic inflammatory cell infiltrate around areas of acellular bone or microscopic sequestra

Classification

Anatomic “MSLD”

Anatomic type	Description
I	Medullary, endosteal disease confined to the medullary canal
II	Superficial, contiguous infection of the outer cortex beneath a soft tissue defect
III	Localised, full thickness cortical sequestration that can be excised without loss of stability
IV	Diffuse, permeative disease with mechanical instability before or after debridement

Host

Host	Description
A	Healthy host with normal physiological, metabolic and immune function (for example WCC over 1,500/mm3, albumin over 3.5 g/dL, protein over 6 g/dL, ferritin 10 to 200 ng/mL, transferrin under 200 mg/dL)
B	Local or systemic compromise, or both
C	Severe compromise, treatment worse than the disease, not a surgical candidate

Original publication Cierny G 3rd, Mader JT, Penninck JJ. A clinical staging system for adult osteomyelitis. Clin Orthop Relat Res. 2003;(414):7-24.

“Clinical” Staging

Complications

• Pathological fracture
• Constant sinus
• Eczematous skin reaction
• Neoplastic change in sinus
• Epidermoid carcinoma in 0.5%
• Malignant bone transformation to sarcoma
• Amyloidosis

Clinical Features

• Recurring bouts of pain, redness, pyrexia & tenderness
• Discharging sinus common
• May have underlying non-union of bone particularly if post-traumatic

Investigations

Laboratory

• WCC, ESR, CRP, blood cultures
• WCC & ESR/CRP may be variably elevated during the flares
• Bacterial cultures need to be repeated regularly to ensure changing sensitivity identified?

X-ray

• Classic picture
  • bone resorption with surrounding sclerosis & thickening
• May have periosteal reaction/ involucrum & very dense sequestrum
• Deformity common
• Features may mimic tumour

Bone Scan

• Increased activity in both the blood pool & bone phases
• More sensitive with WCC-labelled indium scan or gallium scan

CT/MRI

• Show extent of bone destruction & hidden abscesses/sequestra
• Helpful for pre-op planning

Aspiration Biopsy

• 1. Sinus tract cultures
  • Specificity 86%, Sensitivity 76%
  • Isolation of Staph bears little resemblance to organism in bone
  • Isolation of G- bacteria bears no relation to bone
  • Pseudomonas from sinus in bone only 30%
  • Should not be used as guide for AB usage
• 2. Biopsy
  • Preferred diagnostic procedure
  • Increased incidence of multiple organisms
  • Treatment

Treatment

Five Parts

• Appropriate Antibiotics
  • Obtain MCS at time of debridement
  • Commence AB after debridement
• Adequate Debridement
  • Remove necrotic bone
  • Obliterate dead space
• Skeletal Stabilisation
  • External or internal fixation
• Adequate Soft Tissue Cover
  • Introduce healthy vascularised tissue
• Consider Delayed Bone Grafting

Antibiotic Therapy

• Seldom eradicated by antibiotics alone
• Important to
  • Stop spread of infection to healthy bone
  • Control acute flares
• Generally combination of Beta-lactam antibiotic & Aminoglycoside recommended due to synergistic nature & may prevent resistance
• The total period of therapy may be up to 3 months

Local Treatment

• Temporary measures prior to surgical treatment
• Dressings of sinuses
• Drainage of acute abscess

Surgical Treatment

• 1. Debridement
  • Remove all dead & infected material
  • May need to be radical
  • Saucerization of cortex & curettage of medullary contents to bleeding bone
  • Irrigation of area
  • Stabilisation if unstable may be required
  • Often external fixator required
• 2. Soft Tissue & Bony Reconstruction
  • Includes (all considered as closure of dead space)
    • Local muscle flaps
    • Free cancellous bone grafting
    • Free myocutaneous & osteomyocutaneous flaps
    • Vascularised bone graft
    • Bypass grafts
    • Distraction osteogenesis
    • Amputation
  • Local Flaps
    • Not used much due to inability to provide good blood supply & durable soft tissue
  • Open Cancellous Bone Grafting (Papineau technique)
    • First described by Rhinelander in 1975 & then Papineau in 1979
    • For small defects (< 4cm) in a well patient (type A)
    • Defect in bone filled in with cancellous bone chips & dressing applied
    • Changed every few days with debridement of any necrotic bone
    • Process continued until bone graft covered with healthy granulation tissue
    • Then cover by secondary intention, graft or flap
    • Contraindicated in segmental defects > 4cm
  • Free Myocutaneous Flaps
    • 79-100% success
    • Good blood supply
    • Must not transfer to tissue that is still infected
      • doomed to fail
    • Requires good stable underlying bony bed
  • Vascularised Bone Graft
    • Indicated when bony defect > 6cm
    • Best if minimal soft tissue loss but can take with muscle or skin if significant loss
    • Fibula & Iliac crest commonest sites
  • Complications include
    • Loss of graft vascularity
    • Recurrence of infection
    • Delayed/ nonunion of segment
  • Bypass Grafts
    • Cross union established usually between Tibia & Fibula
    • Proximal & distal to defect
    • Allows protection of grafted defect
  • Distraction osteogenesis
    • Ring external fixator (Ilizarov, TSF)
    • May be the only option in large defects
  • Amputation
    • If cannot manage limb with bony defect, instability & persistent infection
    • Maybe indicated early in treatment plan
    • Type C host

Antibiotic Bead Pouch Technique

• Henry & Seligson pioneered technique
• Addition to debridement process
• Reduce bony ablation
• Maintain germ free wound site
• Diaphyseal spacer for later application of bone grafts
• Bead chains used
• Deliver higher concentrations to site but avoid systemic complications
• Can use Gentamicin or Vancomycin
• Involves placing the beads in defect & placing a Non-permeable adhesive dressing over the area & drains without suction in place
• Changed every 48-72 hours in operating theatre

Hyperbaric O2

• Increases O2 tension in tissue beds
• Intramedullary bone O2 tension normally 32-45mmHg; in osteomyelitis 17-23mmHg
• Increased O2 tension
• Toxic to anaerobic bacteria
• Aids neutrophil intracellular bacteriocidal mechanism
• Aids tissue genesis
• Augments bacteriocidal action of aminoglycosides
• Indications not clear at present
• No clear benefit shown

Brodies Abscess

• Localised form of chronic OM occurring most often in long bones of LL in young adults
  • Reflects incomplete healing
  • Caused by organism of low virulence
  • Staph 50%
• Location
  • Metaphyseal in skeletally immature
  • Metaphyseal-epiphyseal in adult
  • May occur rarely in diaphysis
• Clinical
  • Intermittent pain & local tenderness
• Investigations
  • Easily mistaken for tumour on XR
    • Osteoid osteoma
    • Chondroblastoma
    • Enchondroma
    • Eosinophilic granuloma
    • Intraosseous ganglion
    • Giant cell tumour
  • May need Bx
• Treatment
  • Local curettage ± bone graft
  • AB

Chronic Recurrent Multifocal Osteomyelitis

• “CRMO”
• Children & young adults
• Mainly affects
  • Metaphyses of clavicle (most often – 60% at presentation)
  • Tubular bones
  • Can be symmetrical
• Pathology
  • Histologically chronic osteomyelitis with predominance of plasma cells
• Clinical
  • Insidious onset of low grade fever, local swelling & pain in affected bones
  • Symptoms wax & wane over months/ years
  • Intermittent periods of exacerbation & remission over several years
  • Some patients have recurrent skin lesions
  • Palmoplantar pustulosis
• Investigations
  • Cultures negative
  • XR changes suggest OM
  • Bone scan shows multiple areas of involvement
• Treatment
  • Symptomatic
  • Long term prognosis good

Sclerosing Osteomyelitis of Garre

• Garre 1893
• Mainly children & young adults
• Average age 16 years
• Aetiology
  • Unclear aetiology
  • Unusual organisms
    • Propionibacterium acnes (low grade, anaerobic)
• Pathology
  • No necrosis or purulent exudate
  • Little granulation tissue
  • Intense proliferation of the periosteum leading to bony deposition
  • Histologically see non-specific chronic inflammation with new bone formation & areas of necrosis
• Clinical
  • Insidious onset & local pain & tenderness
  • Most common area is
  • Shaft of long bones
  • Other area is Mandible
• Investigations
  • Moderate ↑ in ESR
  • Cultures usually negative
  • See pronounced sclerosis with cystic areas on XR
• May be difficult to distinguish from
  • Ewings
  • Osteosarcoma
  • Osteoid osteoma
  • Osteoblastoma
  • Pagets
• Course
  • Recurrence of symptoms at intervals with eventual subsidence
• Treatment
  • No treatment protocol predictably helpful
  • Fenestration & Curettage provides temporary relief
  • Prolonged antibiotic therapy does not affect natural history

Caffey’s Disease

• Infantile cortical hyperostosis
• Periostitis affecting infants < 6 months of age
• Malaise / fever & swelling of long bones, mandible & scapula
• XR show marked periosteal new bone formation
• Always spontaneously resolves
• Distinguish from scurvy & osteomyelitis & syphilis
• May require antibiotic therapy
  • Penicillin

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.