18F FDG-PET/CT has poor diagnostic accuracy in diagnosing shoulder PJI

Area of Science:

• Orthopedic Surgery
• Nuclear Medicine
• Radiology

Background:

• Chronic low-grade periprosthetic joint infection (PJI) in shoulder replacements presents diagnostic challenges.
• 18F-FDG PET/CT is a recognized tool for diagnosing PJI in lower-limb arthroplasty.
• No prior studies have evaluated 18F-FDG PET/CT for shoulder PJI.

Purpose of the Study:

• To assess the diagnostic accuracy of 18F-FDG PET/CT for chronic PJI in shoulder replacements.
• To investigate the utility of this imaging modality in a challenging clinical scenario.

Main Methods:

• Prospective study of 86 patients with failed shoulder replacements over 3 years.
• Pre-operative 18F-FDG PET/CT performed on all patients.
• Infection diagnosis based on intraoperative cultures (gold standard) and evaluation by three independent reviewers using shoulder-specific criteria.

Main Results:

• 18F-FDG PET/CT demonstrated low sensitivity (0.14) but high specificity (0.91) for detecting shoulder PJI.
• Positive and negative predictive values were 0.40 and 0.71, respectively.
• Moderate inter-observer agreement (Fleiss' kappa = 0.56) was noted for visual PET evaluation.

Conclusions:

• 18F-FDG PET/CT exhibits poor diagnostic accuracy for low-grade PJI in shoulder replacements.
• The study does not recommend 18F-FDG PET/CT as a routine preoperative tool for diagnosing shoulder PJI.