What is the management approach for prosthetic joint hip infections, including classification and treatment options?

Prosthetic Joint Hip Infection: Classification and Management

The management of prosthetic joint hip infections (PJI) requires a structured approach based on infection classification, with surgical intervention determined by symptom duration, prosthesis stability, and pathogen characteristics, combined with appropriate antimicrobial therapy. 1

Definition and Diagnosis of PJI

Definitive Evidence of PJI:

• Presence of a sinus tract communicating with the prosthesis 1
• Purulence around the prosthesis without another known etiology 1
• Two or more intraoperative cultures or combination of preoperative aspiration and intraoperative cultures yielding the same organism 1
• Growth of a virulent microorganism (e.g., S. aureus) in a single specimen of tissue biopsy or synovial fluid 1

Clinical Suspicion:

• Acute onset of a painful prosthesis 1
• Chronic painful prosthesis at any time after implantation, particularly without a pain-free interval 1
• Persistent wound drainage over a joint prosthesis 1

Diagnostic Workup:

• Serum inflammatory markers: ESR and CRP (high sensitivity when combined) 1, 2
• Plain radiographs of the affected joint 1
• Diagnostic arthrocentesis with synovial fluid analysis including:
  • Total cell count and differential leukocyte count 1, 2
  • Culture for aerobic and anaerobic organisms 1
  • Crystal analysis if clinically indicated 1
• Blood cultures if fever is present or acute onset of symptoms 1, 2

Intraoperative Diagnosis:

• Histopathological examination of periprosthetic tissue samples 1
• Collection of 3-6 periprosthetic tissue samples for culture 1
• Withhold antimicrobial therapy for at least 2 weeks prior to collecting specimens when possible 1

Classification and Management Approach

Early PJI (within 30 days of implantation or <3 weeks of symptoms):

• Debridement and retention of prosthesis if:
  • Well-fixed prosthesis 1
  • Absence of sinus tract 1
  • Pathogen susceptible to oral antimicrobials with good bioavailability 1
• This approach has shown up to 92.3% relapse-free survival at 2 years 3

Chronic PJI:

• Two-stage exchange (most common in the US) indicated when:

  • Patient can medically tolerate multiple surgeries 1
  • Reimplantation is possible based on existing soft tissue and bone defects 1
  • Monitor treatment success with pre-revision ESR and CRP 1

• One-stage exchange may be considered for THA infection when:

  • Good soft tissue envelope 1
  • Pathogen identity known preoperatively 1
  • Organism susceptible to oral antimicrobials with excellent bioavailability 1
  • No bone grafting required 1

Salvage Procedures:

• Permanent resection arthroplasty for:

  • Nonambulatory patients 1
  • Limited bone stock or poor soft tissue coverage 1
  • Highly resistant organisms with limited medical therapy options 1
  • Medical conditions precluding multiple surgeries 1
  • Failed previous 2-stage exchange 1

• Amputation as last resort option:

  • Consider referral to specialist center before proceeding 1
  • Reserved for emergent cases or when all other options have failed 1

Antimicrobial Therapy

Chronic Oral Antimicrobial Suppression:

• For oxacillin-susceptible staphylococci: Cephalexin 500 mg PO 3-4 times daily 1
• For oxacillin-resistant staphylococci: Cotrimoxazole 1 DS tab PO twice daily 1
• For β-hemolytic streptococci: Penicillin V 500 mg PO 2-4 times daily 1
• For Pseudomonas aeruginosa: Ciprofloxacin 250-500 mg PO twice daily 1
• For Propionibacterium species: Penicillin V 500 mg PO 2-4 times daily 1

Important Considerations

• Successful management requires strong collaboration between orthopedic surgeons, infectious disease specialists, and other relevant specialists 1
• The duration of symptoms before debridement significantly impacts success rates with prosthesis retention (4.85 vs. 54.24 days for successful vs. failed retention) 4
• Culture-negative PJI occurs in 5-12% of cases due to low-grade infection or prior antibiotic therapy 5
• Delay in diagnosis is associated with poorer outcomes, emphasizing the importance of prompt recognition and treatment 5
• Despite multiple diagnostic tests, no single test provides 100% sensitivity and specificity, necessitating a combination of clinical, laboratory, microbiological, and radiological evaluations 5