Review Question - QID 130

Septic arthritis after anterior cruciate ligament (ACL) reconstruction should be managed with arthroscopic knee I&D and graft retention.

Infection after ACL reconstruction is a rare complication, occurring in <1% of all ACL reconstructions. Typical presentation includes an increase in pain, swelling, and erythema. If inflammatory markers (CRP, ESR) support a suspicion for septic arthritis, joint aspiration should be performed. After diagnosis of an infection following an ACL reconstruction, prompt I&D should be performed, with every attempt made to retain the graft. This may be done arthroscopically and patients may require more than one I&D to ultimately eradicate the infection. In addition to arthroscopic I&D and graft retention, patients should be placed on at least 6 weeks of IV antibiotics, which should be based on cultures.

Judd et al. looked at infections after ACL reconstruction and found 11 patients at their institution over the course of 8 years that were diagnosed with this complication. They noted that prior knee surgery, previous ACL reconstruction, and tibial fixation with a post/washer were risk factors for infection. All infections were successfully dealt with arthroscopically through serial I&Ds (average 2.4 procedures) and graft retention.

Bansal et al. performed a meta-analysis evaluating risk of infection after ACL reconstruction based on graft type. They noted a lower incidence of infection after BPTB autograft compared to hamstring autograft (RR 0.23). They did not identify any increased risk using allografts compared to autografts.

Incorrect Answers:
Answer 1: An open knee arthrotomy would allow for I&D but would increase morbidity compared to arthroscopic management. Additionally, antibiotics are an important adjunct of treatment.
Answer 3, 4, 5: Graft retention should initially be attempted after identification of infection in ACL reconstruction. Bone grafting would not be appropriate in the setting of infection.