What is the management of an abscess around orthopedic (open reduction internal fixation) hardware?

Management of Abscess Around Orthopedic Hardware

The management of an abscess around orthopedic hardware requires prompt surgical drainage of the abscess, followed by appropriate antibiotic therapy covering Gram-positive, Gram-negative, and anaerobic bacteria. 1

Diagnosis

Clinical Evaluation

• Patients with abscess around orthopedic hardware typically present with pain, swelling, tenderness, and possibly systemic symptoms like fever 1
• Hardware-related infections are more common in tarsal (5.56%), tibial (3.65%), and carpal (3.37%) fractures 2
• Risk factors include diabetes mellitus, liver disease, and rheumatoid arthritis 2

Imaging

• MRI is the preferred imaging modality for evaluating suspected infection around orthopedic hardware 1
  • Metal artifact reduction techniques have improved imaging quality around hardware 1
  • MRI allows characterization of both bone marrow signal and adjacent soft tissues 1
  • IV contrast administration helps differentiate abscess from phlegmon 1
• CT with IV contrast is an alternative when MRI is contraindicated 1
  • Helpful in identifying fluid collections adjacent to bone or hardware that can be targeted for drainage 1
  • Can detect necrotic bone fragments or sequestra that may serve as a nidus for chronic infection 1
• FDG-PET/CT has high sensitivity (88%) and specificity (76%) for detecting implant-associated infection 1

Treatment Algorithm

1. Surgical Management

• Prompt surgical drainage is the cornerstone of treatment for abscesses around orthopedic hardware 1
• The goals of surgical intervention include:
  • Draining the abscess expeditiously 1
  • Identifying any fistula tract 1
  • Debriding necrotic tissue 1
  • Evaluating hardware stability and integrity 1
• Large abscesses should be drained with multiple counter incisions rather than a single long incision to prevent step-off deformity and delayed wound healing 1
• For complex or deep abscesses, image-guided drainage may be considered 1

2. Antibiotic Therapy

• Empiric broad-spectrum antibiotics should be administered to cover Gram-positive, Gram-negative, and anaerobic pathogens 1
• Consider MRSA coverage in high-prevalence areas 1
• Obtain cultures during surgical drainage to guide targeted antibiotic therapy 3
• Antibiotic therapy should be adjusted based on culture results and clinical response 1

3. Hardware Considerations

• Decision regarding hardware retention versus removal depends on:
  • Stability of the fracture/fusion 1
  • Duration of infection 2
  • Extent of biofilm formation 2
  • Patient's overall health status 1
• If the hardware is loose or the fracture is healed, removal may be beneficial 2
• If the hardware is stable and necessary for fracture stability, retention with aggressive debridement and antibiotics may be attempted 1

Special Considerations

• Persistent signs of systemic infection require evaluation for endocarditis, especially in intravenous drug users 1
• Foreign bodies should be ruled out by radiography 1
• Duplex sonography should be performed to identify vascular complications 1
• Viral infections (HIV, HCV, HBV) should be ruled out, particularly in high-risk patients 1

Follow-up

• Close monitoring for treatment response is essential 3
• Serial imaging may be necessary to ensure resolution of the abscess 1
• Long-term antibiotic therapy may be required for chronic infections around hardware 1
• Consider infectious disease consultation for complex cases or those with poor response to initial therapy 1

Potential Complications

• Inadequate drainage may lead to persistent or recurrent infection 4
• Bacteremia and sepsis can develop if infection is not properly controlled 4
• Osteomyelitis may develop or worsen if infection extends into bone 1
• Hardware failure may occur, necessitating removal and possible revision surgery 2
• Delayed wound healing and chronic draining sinuses may develop 5