Role of Sonication for Detection of Infection in Explanted Orthopaedic Trauma Implants

Sonication is a new technology that uses high-frequency sound waves to mechanically dislodge bacteria adherent in biofilms. Unlike arthroplasty, its role in orthopaedic trauma has not been described. The goal of this study was to explore the utility of sonication in orthopaedic trauma.

Retrospective review.

Level I trauma center.

One hundred forty-six sonicated metallic orthopaedic devices from September 2010 to May 2013 were included. Patients were divided into 3 groups: clinically infected, elective implant removals, and nonunion.

Sonication culture results were retrospectively reviewed for all patients undergoing implant removal.

Sonication results were the primary study outcome and were considered positive for culture growth if equal to or greater than 20 colony-forming units per plate.

In 32 patients with clinical infection, tissue cultures were positive in 30 (94%) and negative in 2 (6%). In contrast, sonication cultures were positive in 19 patients (59%) and did not identify additional organisms. Of the 72 patients who underwent elective implant removal, 52 had pain. Sonication cultures were positive in 5 of these 52 patients (10%) and in 0 of 20 patients with no pain. Sonication culture results were negative in all 42 patients who underwent nonunion surgery.

Sonication of orthopaedic trauma implants in patients with clinically apparent infection or "aseptic" nonunion offered negligible additional information. Sonication demonstrated a positive microbiologic yield in a subset of patients with painful implants; further research is required to better establish the frequency of subclinical infection and to determine the diagnostic role of traditional cultures and sonication.

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.