II. Risk Factors
- Obesity (highest risk)
- Cardiac disease
- Immunocompromised
- Peripheral Vascular Disease
- Inflammatory Arthritis
- Prior joint infection
- Renal disease
- Liver disease
- Malnutrition
- Alcohol Abuse
- Tobacco Abuse
- Diabetes Mellitus
- Anemia
- Tubb (2020) J Am Acad Orthop Surg 28(8): e340-8 [PubMed]
III. Epidemiology
- Prosthetic Joint Infection carries a 1-2% risk at 2 years and >2% at 10 years
- Nearly half of infections occur in the first 3 months after surgery (nearly 80% occur within first 2 years)
- Prosthetic Hip Joint and Prosthetic Knee Joint infections are responsible for most Prosthetic Septic Joints
IV. Causes
- Early infection
- Staphylococcus epidermidis
- Late Infection
- Gram Positive Cocci (e.g. pneumococcus)
- Anaerobic Bacteria
- Pseudomonas
V. Findings
- See Septic Joint
- Findings are more subtle in infected prosthetic joints than in native joint infections
VI. Diagnosis
- Major Criteria
- Two joint cultures positive for same organism
- Sinus tract communicating with joint
- Minor Criteria
- Intraoperative Criteria (optional)
- Score 3: Histology positive
- Score 3: Purulence
- Score 2: Single Culture Positive
- Interpretation
- Infection
- Either major criteria positive OR
- Minor Criteria Score >6 OR
- Minor AND Intraoperative Criteria >6 (with Minor Score at least 2)
- Inconclusive
- Neither major criteria present AND
- Minor AND Intraoperative Criteria 2 to 5 (with Minor Score at least 2)
- No Infection
- Neither major criteria present AND
- Minor Criteria 0 to 1 (or combined with intraoperative criteria <3)
- Infection
- References
VII. Labs
- See Septic Joint
- Synovasure Lateral Flow Test
- Detects human alpha defensins released by activated Neutrophils
- Positive test suggestive of Bacterial periprosthetic infection
VIII. Imaging
- Nuclear scan
- Negative Nuclear scan excludes septic prosthetic joint
- Pet Scan
- Avoid CT Scan or MRI in infected prosthetic joint
- Does not distinguish infected prosthetic joint from other causes of pain
IX. Management
- See Septic Joint
- Empiric therapy before culture results
- Option 1 (2 drug regimen)
- Drug 1: Vancomycin
- Drug 2: Ciprofloxacin, Aztreonam, or Gentamycin
- Option 2 (2 drug regimen)
- Drug 1
- Ciprofloxacin 750 PO bid or
- Ofloxacin 200 mg PO tid
- Drug 2: Rifampin 900 mg PO qd
- Drug 1
- Option 1 (2 drug regimen)
-
Ciprofloxacin and Rifampin sensitive by culture
- Option 1 (2 drug regimen)
- Drug 1: Ciprofloxacin or Ofloxacin
- Drug 2: Rifampin 900 mg PO qd
- Option 2 (2 drug regimen)
- Option 1 (2 drug regimen)
-
Ciprofloxacin or Rifampin resistance by culture
- Vancomycin and
- Rifampin (if sensitive)
X. References
- Buddendorff (2021) Crit Dec Emerg Med 35(12): 18-9
- Earwood (2021) Am Fam Physician 104(6): 589-97 [PubMed]