What is the management and treatment of chronic osteomyelitis?

Management and Treatment of Chronic Osteomyelitis

The management of chronic osteomyelitis requires a multidisciplinary approach involving radiological assessment, microbiological diagnosis, surgical intervention, and targeted antibiotic therapy based on the specific clinical scenario. 1

Diagnostic Approach

• MRI is the first-line imaging modality for suspected chronic osteomyelitis, with negative MRI results effectively ruling out the condition 2
• Radiography should be performed initially, but has limited sensitivity in early stages of disease 3
• Bone biopsy with culture remains the gold standard for identifying causative organisms, but is not necessary in all cases 1
• Diagnostic algorithm:
  • For visibly necrotic wounds extending to bone: Consider positive for osteomyelitis and refer for surgical debridement with intraoperative cultures 2
  • For unclear wound extension: Obtain MRI 2

Microbiological Diagnosis

• Antibiotics should be discontinued for an optimal period of 2 weeks before obtaining bone cultures 2
• Diagnostic pathway depends on clinical presentation:
  • With septic arthritis: Joint aspiration is usually adequate; if negative, consider percutaneous bone biopsy 2
  • With sinus tract/ulcer: Wound tissue cultures may obviate the need for bone biopsy 2
  • Without alternative sampling sites: Percutaneous image-guided bone biopsy is recommended 2
• Methicillin-susceptible S. aureus is the most common causative organism (29.6%) 4

Surgical Management

• Surgical intervention is required for most cases of chronic osteomyelitis 5, 6
• Key surgical principles:
  • Complete debridement of necrotic bone (sequestrum) is essential 6
  • Intraoperative cultures should be obtained during surgical debridement 2
  • For emergency cases with septic arthritis: Proceed directly to surgical debridement 2
• Surgical options include:
  • Debridement alone (32.8% of cases) 4
  • Debridement with muscle flap (27.4% of cases) 4
  • Amputation in severe cases (7% of cases) 4
  • One-stage antibiotic-mixed cement filling after debridement can allow immediate weight-bearing and avoid staged procedures 7

Antibiotic Therapy

• Antibiotic selection should be based on culture results 5, 6
• Treatment regimens typically include:
  • Initial IV therapy (median 28 days) followed by oral therapy (median 19.5 days) 4
  • Anti-staphylococcal β-lactams (cloxacillin/cefazolin) are most commonly used IV antibiotics (19.2%) 4
  • Fluoroquinolones (ciprofloxacin) are common oral options (5.5%) 4
• Local antibiotic delivery systems:
  • Antibiotic-impregnated cement beads or blocks can provide high local concentrations 7, 5

Special Considerations for Diabetic Foot Osteomyelitis

• MRI has superior accuracy over radiography for diabetic foot osteomyelitis 2
• Bone cultures are recommended when:
  • Diagnosis remains uncertain after clinical and imaging evaluation 2
  • Soft tissue cultures are negative 2
  • Infection fails to respond to initial empirical therapy 2
  • There is high potential for resistant organisms 2

Treatment Outcomes

• Successful treatment (no relapse) occurs in approximately 60.6% of cases 4
• Surgical intervention significantly reduces relapse rates compared to antibiotics alone 4
• Mortality rate is approximately 6.7%, with 3.2% due to infectious complications 4
• Polymicrobial infections are associated with higher treatment failure rates 1

Common Pitfalls and Caveats

• Failure to obtain appropriate cultures before initiating antibiotics can compromise microbiological diagnosis 2
• Inadequate surgical debridement is a major cause of treatment failure and recurrence 5, 6
• The term "remission" is more appropriate than "cure" as infection can recur years after apparent resolution 5
• Antibiotic resistance, particularly methicillin-resistant S. aureus, complicates antimicrobial therapy 5