Septic arthritis of the facet joint

Septic arthritis of the facet joint is a rare clinical entity. We report 11 cases of facet joint infections diagnosed in our institution.

Patients were identified via the computerized patients record (PMSI). Their features were collected and compared with published data.

The clinical symptoms are similar to those of infectious spondylodiscitis: back pain with stiffness (11/11), fever (9/11), radicular pain (5/11), and asthenia. Ten patients presented with lumbar infection and 1 with dorsal infection. An inflammatory syndrome was observed in every case. A rapid access to spine MRI allowed making the diagnosis in every case, and assessing a potential extension of infection (epidural extension 5/11, paraspinal extension 5/11). Blood culture (8/11) or culture of spinal samples allowed identifying the causative bacterium in every case and adapting the antibiotic treatment. The bacteria identified in our series were different from previously reported ones, with less staphylococci. The origin of the infection was found in 4 cases. Another localization of infection was observed in 4 cases. The outcome was favorable with medical treatment in 10 cases. An abscess was surgically drained in 1 case. None of our patients presented with neurological complications, probably because of the rapid diagnosis.

Assessing the facet joint is essential in case of inflammatory back pain, and the radiologist must be asked to perform this examination.