What is the management approach for infections after Anterior Cruciate Ligament (ACL) reconstruction?

Management of Infections After ACL Reconstruction

The management of infections after ACL reconstruction requires prompt diagnosis, aggressive surgical debridement, and appropriate antibiotic therapy, with graft retention as the primary goal whenever possible. 1

Diagnosis of Post-ACL Reconstruction Infections

Clinical Presentation

• Pain, effusion, fever, and elevated inflammatory markers (WBC, ESR, CRP) 2
• Presentation typically occurs around 2-3 weeks post-surgery 2, 3
• May present as draining sinus tract from previous surgical site or subclinical septic arthritis 1
• Important: Infections can be indolent with normal initial laboratory values (ESR/CRP) 1

Diagnostic Workup

• Joint aspiration is the gold standard diagnostic test 2
  • Send for cell count, gram stain, and culture
  • Send as much material as safely possible to the laboratory 1
• Specifically request mycobacterial cultures when standard cultures are negative 1
  • Do not send swabs (limited material, subject to desiccation)
  • Do not wrap tissue in gauze or dilute in liquid material
• MRI may help identify extra-articular involvement or fistulous tracts 4

Treatment Algorithm

1. Initial Management

• Start empirical antibiotics immediately upon suspicion of infection 1, 2
• Perform prompt arthroscopic irrigation and debridement 5, 2, 6
• Obtain multiple tissue samples during debridement for culture 1

2. Surgical Management

• Perform thorough arthroscopic debridement 2
• Graft retention is possible in most cases if:
  • Graft appears stable and intact 5
  • No evidence of intra-articular involvement 4
  • Early diagnosis and treatment 3
• Consider hardware removal (particularly metallic implants) 3, 4
• Multiple debridements may be necessary (average 2.25-2.4 procedures) 5, 6

3. Antibiotic Therapy

• Initial IV antibiotics for 2 weeks followed by oral antibiotics for 4 weeks 2
• Adjust based on culture and sensitivity results 1
• For nontuberculosis mycobacterium (NTM) infections:
  • Consult infectious disease specialist 1
  • Severe infections may require IV antibiotics followed by oral therapy for 6-12 months 1
  • Duration depends on bacterial burden and patient's immune status 1

4. Special Considerations for NTM Infections

• Complete excision of infected tissues is essential 1
• All fixation and graft materials as well as associated bone should be removed or debrided 1
• Targeted antimicrobial therapies based on susceptibility testing 1

Expected Outcomes and Follow-up

• Success rates with graft retention: 93-97% 3, 6
• Average Lysholm functional scores: 71-81 points 5, 3
• Knee stability can be maintained with KT-1000 side-to-side differences of 1.4-2.7mm 3, 6
• Most common complaints in patients with fair/poor results: pain and stiffness 5
• Monitor CRP levels until normalization 6
• Long-term follow-up to assess for recurrence

Common Pathogens

• Most common organisms:
  • Staphylococcus aureus (21-22%) 3, 6
  • Coagulase-negative staphylococci (62.5%) 6
  • Nontuberculosis mycobacterium (NTM) in culture-negative cases 1

Prevention of Complications

• High index of suspicion for indolent infections, especially with negative cultures 1
• Early diagnosis and intervention are critical for graft salvage 1
• Multidisciplinary approach with infectious disease specialists for complex cases 1
• Consider NTM in cases unresponsive to standard antibacterial treatments 1

The management of infections after ACL reconstruction requires balancing the goals of eradicating infection while preserving the graft and knee function. With prompt diagnosis, aggressive surgical debridement, and appropriate antibiotic therapy, excellent outcomes can be achieved in most cases, though results are typically lower than with uncomplicated ACL reconstructions.