False-negative synovial alpha-defensin

Area of Science:

• Orthopedics
• Infectious Diseases
• Diagnostic Biomarkers

Background:

• Periprosthetic joint infection (PJI) is a serious complication following total hip arthroplasty.
• Accurate diagnosis of chronic PJI is crucial for effective treatment and patient outcomes.
• The alpha-defensin test has emerged as a promising biomarker for PJI diagnosis.

Observation:

• This case report details a patient with chronic periprosthetic hip infection.
• The infection was diagnosed using the established Musculoskeletal Infection Society (MSIS) criteria.
• The alpha-defensin synovial fluid test yielded a false-negative result in this patient.

Findings:

• The study presents the first reported instance of a false-negative alpha-defensin test in a patient with an open sinus tract communicating with a culture-positive total hip implant.
• The diagnostic workup revealed discrepancies between the alpha-defensin test and clinical/microbiological findings.
• Potential reasons for the false-negative alpha-defensin result are discussed.

Implications:

• The findings suggest that the alpha-defensin test should be interpreted with caution and in conjunction with comprehensive clinical data.
• In specific clinical situations, such as the one described, the MSIS criteria may offer superior diagnostic performance compared to the alpha-defensin test.
• This case underscores the importance of considering multiple diagnostic modalities for periprosthetic hip infections.