prosthetic joint infection

• related: septic arthritis, MSK, Infectious Disease

Prosthetic Joint Infection

Prosthetic joint infection
	Early onset	Delayed onset	Late onset
Time to onset after surgery	<3 months	3-12 months	>12 months
Presentation	Acute pain. Wound infection or breakdown. Fever	Chronic joint pain. Implant loosening. Sinus tract formation	Acute symptoms in previously asymptomatic joint. Recent infection at distant site
Most common organisms	Staphylococcus aureus. Gram-negative rods. Anaerobes	Coagulase-negative staphylococci. Propionibacterium species. Enterococci	Staphylococcus aureus. Gram-negative rods. Beta-hemolytic streptococci

• early onset: < 3 months, staph aureus
• delayed onset: 3-12 months, CoNS, S. epidermidis
• late onset: > 12 months: staph aureus

PJI can be acquired by perioperative contamination of the joint or by extension from an overlying wound infection:

• Infections due to virulent organisms (eg, Staphylococcus aureus, Pseudomonas aeruginosa) typically present within the first 3 months after surgery (early onset infection) with acute pain, fever, leukocytosis, and overt local signs of infection (eg, erythema, purulent drainage), not seen in this patient.
• Infections due to less virulent organisms (eg, coagulase-negative staphylococci, Propionibacterium species), as in this patient, are likely to have a delayed onset (3-12 months) and present with chronic pain, implant loosening, gait impairment, or sinus tract formation. Fever and leukocytosis are usually absent. Staphylococcus epidermidis is a coagulase-negative staphylococcus commonly implicated in delayed-onset PJI.
• Late-onset infections presenting >12 months after surgery are unlikely to have been acquired perioperatively and are usually due to hematogenous spread of a distant infection (eg, urinary tract infection).

• prolonged, low grade onset
• minimal swelling
• can present acutely

• xray: prosthesis loosening, periosteal reaction

Links to this note

• Infectious Disease
  • prosthetic joint infection
• MSK
  • prosthetic joint infection
• septic arthritis
  • related: MSK, Infectious Disease, pediatric septic arthritis, osteomyelitis, prosthetic joint infection, notes, arthrocentesis

• removal of prosthesis
• IV a bx 6-8 weeks

This patient has subacute pain in his prosthetic knee 6 months after arthroplasty. The synovial fluid analysis shows a mildly elevated leukocyte count with a predominance of neutrophils. This is consistent with an inflammatory process, most likely a prosthetic joint infection (PJI). The leukocyte count in the synovial fluid in PJI is usually elevated to >1000/mm3 but is often lower than in septic native joints (usually >50,000/mm3).