Computed tomography of septic joints.

Twenty-six patients with suspected or known septic joints who had been studied by computed tomography were retrospectively reviewed. Eighteen patients (20 joints) proved to have septic arthritis. Computed tomography was advantageous in patients with acute septic arthritis of deep-seated axial joints, such as the hip and sacroiliac, where it demonstrated particular soft tissue swelling as early as 36 hours after the onset of symptoms. In three patients, this finding on computed tomography was helpful in accurately localizing the disease process and facilitating a diagnostic closed needle aspiration biopsy procedure. Four patients had a primary osseous focus of infection in an adjacent epiphyseal region that was documented by computed tomography. Computed tomography was superior to conventional radiology in revealing early articular bone erosion in joints with curved and overlapping articular surfaces in five patients, and resulted in alteration of their treatment. Fat-fluid levels within the suprapatellar bursae were noted in one patient (two joints). Computed tomography is a valuable modality for evaluation of patients with suspected septic arthritis of axial joints, particularly in the acute stage. Furthermore, it is helpful for evaluation of possible periarticular abscess formation and can serve as a guide for a percutaneous drainage procedure. Computed tomography can also be used when articular bone erosion or medullary extension of osteomyelitis is suspected but not fully documented by conventional radiography.