Host Inflammatory Response During Periprosthetic Infection Is Joint Specific

Area of Science:

• Orthopedic Surgery
• Infectious Diseases
• Microbiology

Background:

• Propionibacterium acnes (P. acnes) is an emerging cause of periprosthetic joint infection (PJI).
• Clinical presentation of P. acnes PJI may differ based on the infected joint.

Purpose of the Study:

• To investigate if the clinical presentation of P. acnes periprosthetic joint infection (PJI) differs between hip, knee, and shoulder arthroplasty.

Main Methods:

• Retrospective review of patients with P. acnes PJI after hip, knee, or shoulder arthroplasty.
• Classification of PJI using Musculoskeletal Infection Society criteria.
• Exclusion of polymicrobial cultures; analysis of demographics, preoperative labs, and microbiology.

Main Results:

• P. acnes PJI identified in 18 knees, 12 hips, and 35 shoulders.
• Significantly higher median ESR and C-reactive protein in knee and hip PJI compared to shoulder PJI.
• Elevated synovial fluid WBC in knee PJI versus shoulder PJI; clindamycin resistance noted in all groups.

Conclusions:

• The clinical presentation of P. acnes PJI is joint-specific.
• Elevated inflammatory markers (ESR, CRP, synovial WBC) are characteristic of knee and hip PJI compared to shoulder PJI.
• Extended anaerobic cultures (up to 14 days) are crucial for accurate P. acnes identification.