Prosthetic joint infection
Prosthetic joint infection (PJI) is bacterial, rarely fungal, colonization of a hip or knee implant, complicating 1 to 3% of arthroplasties. Diagnosis rests on a sinus tract or multiple matching periprosthetic cultures. Management always combines surgery, debridement with implant retention or staged prosthesis exchange, with pathogen-directed antimicrobial therapy.
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What this article covers
- Overview
Definition: Prosthetic joint infection (PJI) is microbial colonization of a hip, knee, or other joint implant and its bone-cement interface, most often bacterial, occasionally fungal.
- Epidemiology
Frequency: PJI complicates 1 to 3% of total hip and knee arthroplasties, the leading cause of early revision surgery.
- Risk factors
Rheumatoid arthritis: Immune dysfunction and immunosuppressive therapy both raise risk, particularly around surgery.
- Pathophysiology
Route of inoculation: Organisms enter directly at arthroplasty, from skin flora or operating room contamination, or later via hematogenous spread from a distant site.
- Clinical features
Timing-based classification (definitions vary, this scheme is most consistent): Early-onset infection develops within 3 months of surgery, delayed-onset 3 to 12 months, late-onset beyond 12 months…
- Differential diagnosis
Aseptic mechanical loosening: Activity-related pain and radiographic lucency, but inflammatory markers and synovial leukocyte counts are normal and cultures stay negative.
- Diagnosis
What establishes the diagnosis: A sinus tract communicating from the skin to the prosthesis, growth of the same organism from multiple periprosthetic specimens obtained at the same procedure, or a…
- Management
First, involve orthopedic surgery: Every suspected PJI needs surgical consultation, because cure always requires a combined strategy; antibiotics alone do not clear a biofilm-coated implant.
- Complications
Bacteremia and endocarditis: Untreated PJI can seed the bloodstream, risking secondary endocarditis, particularly with S aureus.
- Prognosis
Case selection drives outcome: DAIR succeeds best performed early, with a well-fixed implant, healthy soft tissue, and short symptom duration; delayed recognition or a loose implant favors exchange instead.
- Prevention
Preoperative surgical prophylaxis: Cefazolin 2 g IV under 120 kg (3 g at or above), infused within 60 minutes before incision, redosed intraoperatively every 4 hours if surgery continues that long or…
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