Treatment of Osteomyelitis After Failed Antibiotic Course

Diagnostic Evaluation

When initial antibiotic therapy fails, clinicians should consider several possible reasons, including residual necrotic/infected bone, inappropriate antibiotic selection, inadequate antibiotic penetration into bone, insufficient treatment duration, or non-infectious complications, as recommended by the Infectious Diseases Society of America 1
Plain radiographs should be used as first-line imaging due to availability and low cost, according to the Infectious Diseases Society of America 1
MRI is the most accurate imaging study for defining bone infection and should be considered when diagnosis remains uncertain, as stated by the Radiological Society of North America 1, 2
Bone biopsy is strongly recommended after failed treatment to confirm persistent infection, identify causative organisms and their antibiotic susceptibilities, and guide appropriate antibiotic selection, as recommended by the American Diabetes Association 3, 4

Surgical intervention should be strongly considered after failed antibiotic therapy, particularly in scenarios with substantial bone necrosis or exposed joint, functionally compromised foot, presence of infecting pathogens resistant to available antibiotics, limb with uncorrectable ischemia limiting antibiotic delivery, or patient preference for surgical treatment, as recommended by the American Diabetes Association 5
Surgical options include debridement of infected and necrotic bone, resection of infected bone, amputation when necessary, and antibiotic-impregnated beads, sponges, cement or orthopaedic implants in selected cases, as stated by the Infectious Diseases Society of America 4, 5

Antibiotic selection should be based on bone culture results rather than soft tissue cultures, as recommended by the Infectious Diseases Society of America 6, 4
For empiric therapy, regimens should usually cover Staphylococcus aureus as it is the most common pathogen, according to the American Diabetes Association 3
Parenteral therapy is traditionally recommended initially, but oral antibiotics with good bioavailability may be equally effective, as stated by the American Diabetes Association 3
Oral antibiotics with good bone penetration include fluoroquinolones, rifampin, clindamycin, linezolid, fusidic acid, and trimethoprim-sulfamethoxazole, as recommended by the American Diabetes Association 3
The duration of therapy depends on the treatment approach, with shorter courses (2-14 days) sufficient if infected bone is surgically removed, and 4-6 weeks of therapy typically recommended for non-surgical management, as stated by the Infectious Diseases Society of America 3, 7

Non-surgical management with antibiotics alone might be considered in specific situations, such as no acceptable surgical target, patient has limb ischemia caused by unreconstructable vascular disease but wishes to avoid amputation, infection is confined to the forefoot with minimal soft tissue loss, or patient and healthcare professional agree that surgical management carries excessive risk, as recommended by the Infectious Diseases Society of America 1, 4

For patients with apparently incurable infection, consider long-term suppressive antibiotic therapy, intermittent short courses of treatment for recrudescent symptoms, or percutaneous bone biopsy for culture to determine if there is persistent infection or changes in pathogens or antibiotic susceptibilities, as recommended by the American Diabetes Association 3

Relying on soft tissue cultures rather than bone cultures to guide antibiotic therapy, as warned by the Infectious Diseases Society of America 6, 4
Continuing the same antibiotic regimen that previously failed, as cautioned by the Infectious Diseases Society of America 1
Inadequate surgical debridement of necrotic bone, as warned by the Infectious Diseases Society of America 4
Not addressing vascular insufficiency which may limit antibiotic delivery to infected bone, as cautioned by the Infectious Diseases Society of America 4