Clinically unsuspected orthopedic implants during S. aureus bacteremia do not require additional diagnostic work-up

Area of Science:

• Infectious Diseases
• Orthopedic Surgery
• Nuclear Medicine

Background:

• Orthopedic implants can be a site for metastatic infection during Staphylococcus aureus bacteremia (SAB).
• Assessing occult infections in patients with clinically unsuspected orthopedic implants during SAB is crucial.

Purpose of the Study:

• To determine the incidence of occult orthopedic implant infections in patients with Staphylococcus aureus bacteremia (SAB).
• To evaluate the utility of [18F]FDG-PET/CT in detecting implant infections in unsuspected cases.

Main Methods:

• Retrospective study of SAB patients with orthopedic implants between 2013-2020.
• [18F]FDG-PET/CT imaging was used to assess implant-related infections.
• Comparison of clinical parameters between suspected and unsuspected implant infections.

Main Results:

• Of 136 unsuspected orthopedic implants, only 5 (3%) arthroplasties showed increased [18F]FDG uptake.
• No evidence of prosthetic joint infection or relapse of bacteremia was observed during a median 48-month follow-up.
• 55 of 191 (29%) implants in SAB patients had clinical signs of infection.

Conclusions:

• Orthopedic implants are a risk factor for metastatic infection in SAB.
• Absence of clinical symptoms in patients with unsuspected implants suggests no need for further investigation or prolonged antibiotic therapy.
• Routine [18F]FDG-PET/CT may not be indicated for all orthopedic implants during SAB without clinical suspicion.