What is the management approach for an infected periprosthetic fracture (PF) of the hip using a hip spacer?

Management of Infected Proximal Femoral Nail (PFN) Using Hip Spacer

For an infected proximal femoral nail (PFN), a two-stage exchange procedure with an antibiotic-impregnated cement spacer is the recommended treatment approach to eradicate infection and maintain hip function. 1

Initial Surgical Management

• Remove all infected hardware components (PFN) and perform thorough debridement of infected periprosthetic tissue 1
• Obtain multiple tissue samples (minimum 3) for culture to identify causative organisms 1
• After debridement, place an antibiotic-impregnated cement spacer to:
  • Maintain joint space and soft tissue tension 1
  • Deliver high local concentrations of antibiotics 1
  • Allow some degree of mobility between stages 1

Spacer Design Considerations

• Use a molded articulating spacer with an endoskeleton (e.g., Steinmann pin) to reduce mechanical complications 2, 3
• Restore appropriate leg length and offset to minimize dislocation risk 3
• Consider using dual mobility components for increased stability 4
• Pay special attention to patients with extended trochanteric osteotomies who have higher rates of mechanical complications 5

Antibiotic Selection for Spacer

• Choose antibiotics based on thermal stability at body temperature (aminoglycosides, glycopeptides, and fluoroquinolones show excellent stability) 1
• Commonly used antibiotics in commercial formulations include gentamicin, tobramycin, vancomycin, and clindamycin 1
• For MRSA infections, some experts recommend against using spacers, though this remains controversial 1

Antimicrobial Therapy

• Administer pathogen-specific intravenous antibiotics for 2-6 weeks following spacer placement 1
• For staphylococcal infections, consider rifampin-based combination therapy if organisms are susceptible 1

Timing of Reimplantation

• Standard approach: 4-6 weeks of intravenous antimicrobial therapy followed by an antibiotic-free period of 2-8 weeks before reimplantation 1
• Monitor inflammatory markers (CRP, ESR) before reimplantation to assess treatment success 1
• Consider joint aspiration before reimplantation in selected cases with concern for persistent infection 1

Potential Complications

• Mechanical complications occur in approximately 20-26% of cases 2, 3:
  • Spacer dislocation (8-15%) 3, 5
  • Spacer fracture (8-9%) 3, 5
  • Periprosthetic fracture (0.7-18%) 2, 5
• Risk factors for complications include:
  • Inadequate restoration of femoral offset 3
  • Extended trochanteric osteotomy 5
  • Handmade versus molded spacers 3

Second-Stage Procedure

• Perform thorough debridement during reimplantation 1
• If infection is suspected during reimplantation based on intraoperative findings, perform additional debridement 1
• Both cemented and non-cemented prostheses can be used for definitive reconstruction depending on technical factors 1

Special Considerations

• Long-term retention of spacers is not recommended due to progressive complications including stem fracture and bone resorption 6
• For fracture-related infections, consider that biofilm maturation occurs over weeks, with declining success rates for implant retention as time elapses post-fixation 1
• Success rates for implant retention decrease from 90% (within 3 weeks of fixation) to 51-67% (after 10 weeks) 1

Monitoring and Follow-up

• Assess inflammatory markers (CRP, ESR) regularly to monitor infection control 1
• Perform radiographic evaluation to detect mechanical complications such as spacer migration, fracture, or dislocation 3
• Overall success rate for two-stage exchange in hip PJI is approximately 87% 1