Knee joint infection after ACL reconstruction: prevalence, management and functional outcomes

Septic arthritis after an ACL reconstruction is a rare but serious complication. Functional outcomes of these patients have not been studied in depth in large series. The aim of this study was to determine the prevalence and management of knee joint infection following ACL reconstruction and to assess the functional outcomes. A retrospective assessment of knee joint infections occurring after arthroscopically assisted ACL reconstructions done from 2006 to 2009 in two hospitals by the same surgical team is presented. Patients with signs and symptoms of joint infection along with blood and synovial effusion laboratory parameters suggestive of infection were considered as septic arthritis. All the patients were treated with antibiotic therapy according to antibiotic sensitivity and had at least one arthroscopic lavage. Final outcomes were assessed and compared with a control group using the KT-1000 arthrometer, functional testing and radiological examination. Fifteen (1.8 %) out of 810 patients included in the study were considered as a joint infection. Microbiology showed that coagulase-negative Staphylococcus was present in 10 patients, Staphylococcus Aureus in three patients (2 MSSA and 1 MRSA) and Propinebacterium sp. in one patient. In one patient, the micro-organism was unknown. At a mean follow-up of 39.3 +/- A 13 months, the Lysholm score was 77.7 +/- A 15.3, the IKDC score was 70.4 +/- A 19.5, and the KT-1000 compared to the non-injured contralateral knee showed a mean difference of 1.3 +/- A 2 mm. Functional outcomes in the control group were slightly better than those obtained in the infected group (Lysholm score; 90.7 +/- A 9.4, p = 0.007. IKDC score; 86.6 +/- A 6.8, p = 0.004). All but one patient retained their reconstructed ACL. The prevalence of septic arthritis after an ACL reconstruction in this series was 1.8 %. Arthroscopic lavages along with antibiotic treatment led us to preserve all but one graft. Functional outcomes in the infected patients were not as good as those obtained in patients without infection. Therapeutic case series, Level IV.