Prosthetic Joint Infection
System: Bone and Joint Infections · Parent MOC: MOC - Diseases by System
One-Sentence Definition
Prosthetic joint infection (PJI) is infection of a joint arthroplasty — usually by hematogenous seeding or perioperative contamination — diagnosed by combined clinical, laboratory, histopathology, and culture criteria, often involving Biofilm on implant surfaces.
Clinical Presentation
- Pain, swelling, warmth, sinus tract, loosening — acute or indolent
- May present as persistent wound drainage early or late hematogenous seeding years later
- Low-grade fever; systemic signs variable
Pathogens
| Timing / context | Organisms | Notes |
|---|---|---|
| Early (<3 mo) | Staphylococcus aureus, coagulase-negative staph, streptococci | Perioperative |
| Delayed | CoNS, Cutibacterium (formerly P. acnes) | Biofilm |
| Late hematogenous | Staphylococcus aureus, streptococci, Gram-negatives | Dental/GI/UTI bacteremia seeding |
| Polymicrobial | Mixed skin/GI flora | Less common |
Pathogenesis
- Implant surface → Biofilm → antibiotic tolerance, poor immune access
- Synovial fluid leukocytosis; prosthesis-adherent bacteria
Diagnosis
| Step | Test | Note |
|---|---|---|
| Labs | ESR/CRP (supportive) | Elevated in many PJIs |
| Key fluid | Synovial WBC count + PMN % | Per validated cutoffs for joint |
| Micro | Aerobic/anaerobic cultures (multiple specimens) | Hold antibiotics when safe pre-op |
| Intra-op | Tissue histology + periprosthetic cultures | MSIS-style criteria |
| Do not rely on | Single superficial swab | Contamination risk |
Treatment Principles
- Combined surgery + prolonged antibiotics — DAIR, one-stage/two-stage exchange per case
- Empiric coverage for staphylococci ± Gram-negatives until cultures
- ID + orthopedics co-management; rifampin combinations only with stable biofilm-disrupted hardware per guidelines
Prevention
- Perioperative prophylaxis; skin prep; laminar flow
- Dental/UTI bacteremia awareness in prosthetic joint patients (guideline-specific prophylaxis debates)
Differential / Pitfalls
- Aseptic loosening, crystal arthropathy, mechanical failure
- Propionibacterium — slow-grower; extend culture holds
- Contaminant coagulase-negative staph — interpret with criteria
Related
- Septic Arthritis · Acute Osteomyelitis · Device-Associated Infections
- Staphylococcus aureus · Biofilm · MOC - Antimicrobial Stewardship
Active Recall
- Why is biofilm central to PJI therapy?
- Synovial fluid tests vs superficial swab?
- Name two common early vs late organisms.