Background
Bacterial and septic arthritis of the large peripheral joints represent an acute emergency. Staphylococcus aureus is still the most common pathogenic agent encountered. Bacterial infections are most frequently seen in the knee joints, followed by the hip and shoulder joints.
Aim
Various radiological imaging modalities and their findings with respect to diagnosis and evaluation of infectious involvement of the large joints are presented. Furthermore, a diagnostic algorithm is proposed.
Material and methods
A comprehensive, unsystematic review of the literature was carried out with special reference to the author’s experiences.
Results and conclusion
Whereas the hematogenous pathway of bacterial spread is most often encountered in children, exogenous infections due to prosthetic surgery and other operative joint procedures, injections and juxta-articular infections are more frequently the cause of joint infections in adults. Imaging modalities are of utmost importance for the diagnostic work-up of septic arthritis. In particular, magnetic resonance imaging (MRI) enables an early diagnosis of septic arthritis with high diagnostic reliability and is therefore the method of choice. The determination of therapeutically relevant pathogens and the differential diagnostic distinction from non-bacterial arthritis are carried out by arthrocentesis. Other imaging modalities, such as computed tomography (CT), bone scintigraphy, and fluorodeoxyglucose positron emission tomography (FDG-PET) are of less importance. Imaging alone can identify and reliably assess complications, such as joint empyema and abscesses, chondrolysis, osteomyelitis, osteonecrosis, joint surface collapse and joint destruction. Imaging is also suitable for follow-up examinations and prognostic evaluation regarding persisting articular damage.