No need to search for the source of haematogenous arthroplasty infections

Prosthetic joint infections (PJI) may be a potential sentinel event for an unknown neoplastic or infectious source in elderly patients. However, the value and cost-effectiveness of investigations to determine the origin of these infections is unknown.

Retrospective study at Geneva University Hospitals, evaluating associated medical examinations performed in search of the origin of all presumed surgical site and haematogenous arthroplasty infections.

A total of 182 PJI were found in 182 patients (median age 75 years). Seventy PJI (38%) were classified as probably haematogenous, occurring more than 2 years post-implantation, with 27 (15%) due to Gram-negative pathogens. Overall, the origin of PJI was found solely by admission history in 28 cases (15%). Among the remaining 154 cases, no remote origin could be detected despite 17 echocardiograms, 17 other sonograms, 49 chest x-rays, 23 computed tomograms, 107 urinary cultures, 11 endoscopies, 9 scintigraphies and 31 medical specialist consultations. The average cost of these exams was 675 Swiss francs (845 US$) per PJI. At long-term follow-up six patients were found to have developed a neoplasm, of which only one (hepatocellular carcinoma after PJI due to Streptococcus bovis) could eventually be attributed to prior infection.

From an epidemiologic point of view, patient history is the best way to predict the origin of PJI. Blind additional radiographic or endoscopic exams are costly, inconclusive and do not contribute to the management of these cases.