Diagnostic value of computed tomography in periprosthetic infections of the hip

Metin Manouchehr Eskandari; Caner Özer; Cengiz Yılmaz; Gülden Ersöz; Alper Gölpınar; Fehmi Kuyurtar

Metin Manouchehr Eskandari¹, Caner Özer², Cengiz Yılmaz¹, Gülden Ersöz³, Alper Gölpınar¹, Fehmi Kuyurtar¹

¹Departments of Orthopedics and Traumatology Medicine Faculty of Mersin University
²Departments of Radiodiagnostics Medicine Faculty of Mersin University
³Departments of Infection Diseases Medicine Faculty of Mersin University

Keywords: Diagnosis, differential; hip prosthesis/adverse effects; prosthesis failure; prosthesis-related infections/radiography; sensitivity and specificity; tomography, X-ray computed.

Abstract

Objectives: Computed tomography (CT), despite its value in the diagnosis of musculoskeletal infections, is rarely used in periprosthetic infections of the hip because of excessive metal artifacts. This study was designed to determine the efficacy of CT in suspected cases of periprosthetic hip infections.
Patients and methods: The study included 20 patients (21 hips; 14 females, 6 males) who were examined by CT scans due to high suspicion of infections following hip arthroplasties. Ten patients had a history of infection or drainage after the first operation and 10 patients had local infection findings. The mean age of the patients was 71.1 years (range 46 to 84 years). Evaluations to seek evidence for infections included erythrocyte sedimentation rate, serum C-reactive protein level, direct radiographs of the hips, CT, aspiration in the absence of an active drainage, perioperative Gram staining and microscopic examination of surgical specimens, and postoperative microbiologic studies. Sensitivity, specificity, positive predictive and negative predictive values of each method were calculated with reference to intraoperative macroscopic findings.
Results: On the basis of intraoperative macroscopic findings, a definitive diagnosis of infection was made in 13 hips. Among the methods used, CT had the highest sensitivity (92.3%; 12/13) and negative predictive value (87.5%; 7/8), and was in the second place with its specificity (87.5%; 7/8), and positive predictive value (92.3%; 12/13).
Conclusion: Our data suggest that CT is a highly useful diagnostic tool in distinguishing periprosthetic infections of the hip from other causes that mimic an infectious state.