Courtesy: Thurston Gehrke,m Ashok Shyam, IORG, OrthoTV

Periprosthetic Joint Infection (PJI): Diagnosis and Management

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Overview

• Periprosthetic Joint Infection (PJI) is a major complication after:
  • Total hip replacement
  • Total knee replacement

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Clinical Importance

• Difficult to diagnose
• Challenging to treat
• Significant impact on:
  • Patient outcomes
  • Healthcare systems

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Challenges in Diagnosis

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Limitations of Traditional Markers

• C-reactive protein (CRP):
  • May be normal in some infected cases
• Erythrocyte sedimentation rate (ESR):
  • Often unreliable

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Biological Challenges

• Bacteria may:
  • Hide within cells
  • Reside in bone canaliculi
  • Form biofilms — evade detection

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Modern Diagnostic Approach

• Use of standardized algorithms:
  • International Consensus Meeting (ICM) criteria

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Clinical Scenario (Typical Presentation)

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• Increasing joint pain after a pain-free period
• Suspicion of infection — further evaluation required

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Aspiration Technique

• Performed under:
  • Fluoroscopy
  • Strict sterile conditions

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Diagnostic Findings

• Elevated:
  • Synovial cell count
  • Polymorphonuclear (PMN) percentage

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Key Diagnostic Modalities

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1. Synovial Fluid Analysis

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Parameters

• Cell count
• PMN percentage
• Alpha defensin
• Leukocyte esterase

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Important Tool

• Leukocyte esterase test:
  • Sensitive
  • Cost-effective

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2. Culture and Biopsy

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Indications

• Culture-negative cases

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Approach

• Repeat aspiration
• Open biopsy

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3. Molecular Diagnostics

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Techniques

• Broad-range 16S PCR
• Multiplex PCR
• Next-generation sequencing (NGS)

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Advantages of NGS

• Detects polymicrobial infections
• Identifies resistance genes

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Limitations

• High cost
• Complex interpretation

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Treatment Approach

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Core Principle

• Multidisciplinary management is essential

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Team Involves

• Orthopaedic surgeon
• Microbiologist
• Infectious disease specialist

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Surgical Strategies

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1. Two-Stage Exchange (Conventional Standard)

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Steps

1. Implant removal
2. Debridement
3. Antibiotic spacer
4. Delayed reimplantation

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2. One-Stage Exchange (Emerging Trend)

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Features

• Single surgery
• Removal + reimplantation in same sitting

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Advantages

• Reduced morbidity
• Faster recovery

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Requirement

• Known organism
• Good soft tissue condition

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Key Surgical Principles

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• Thorough debridement
• Appropriate antibiotic therapy
• Use of antibiotic-loaded cement
• Strict aseptic technique:
  • Re-draping
  • New instruments during reimplantation

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Implant Considerations

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Hip

• Dual mobility cups — reduce instability

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Knee

• Hinged prosthesis:
  • In cases of extensive debridement

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Evidence and Outcomes

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One-Stage vs Two-Stage

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• Comparable or better outcomes in selected patients
• High success rates:
  • Infection eradication
  • Reimplantation

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Factors Affecting Success

• Identification of organism
• Antibiotic sensitivity
• Patient comorbidities
• Adequacy of debridement

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Key Take-Home Messages

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• Diagnosis requires a combined approach:
  • Clinical
  • Laboratory
  • Imaging

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• Highly useful tests:
  • Leukocyte esterase
  • PMN percentage

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• Culture-negative cases:
  • Repeat aspiration or biopsy

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• Multidisciplinary care improves outcomes

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• One-stage exchange is an effective option in selected patients