What is the management approach for an older adult with potential comorbidities (e.g. diabetes) who develops an infection after Total Hip Replacement (THR)?

Management of Infection After Total Hip Replacement

For an older adult with potential comorbidities like diabetes who develops infection after THR, the optimal management approach prioritizes surgical intervention combined with prolonged antimicrobial therapy, with the specific surgical strategy determined by infection timing and clinical presentation. 1

Initial Diagnostic Approach

Critical warning signs that distinguish post-operative infection from normal inflammation include:

• Pain persisting beyond 6 months after joint replacement 2
• Presence of a draining sinus tract from the surgical site (pathognomonic of prosthetic joint infection) 1, 2
• Wound discharge persisting for 5 or more days postoperatively 1

For persistent wound drainage (≥5 days), perform arthrotomy with thorough debridement and collect minimum of three intraoperative tissue specimens rather than superficial swabs, which are misleading and promote unnecessarily broad antimicrobial treatment. 1

Key laboratory considerations:

• ESR and CRP can remain elevated normally for up to 2 months post-surgery, making interpretation challenging 2
• When both ESR and CRP are negative, infection is unlikely, but positive results warrant joint aspiration 3
• Initial laboratory values may be within normal range even with established infection, especially with atypical organisms 2

Surgical Management Algorithm

The surgical approach depends critically on infection timing and clinical factors: 1

Debridement and Implant Retention (DAIR)

Appropriate for:

• Early infections (<30 days post-implantation) 4
• Acute hematogenous infections with short symptom duration (<3 weeks) 4
• Involves arthrotomy, debridement, and exchange of removable components (polyethylene insert, acetabular liner, modular femoral head) 1

Two-Stage Exchange (Preferred for Most Cases)

Indicated for: 1, 4

• Infections presenting >30 days post-implantation with prolonged symptoms
• Prosthesis loosening
• Presence of sinus tract
• Significant periprosthetic tissue damage
• Failed DAIR attempt

Two-stage protocol: 1, 5

• Stage 1: Remove infected prosthesis (including all cement), insert antibiotic-impregnated cement spacer
• Interval period: Minimum 1 year between resection and reimplantation significantly reduces recurrence (7% vs 27% when <1 year) 5
• Complete cement removal is critical: Retained cement increases recurrence risk (43% vs 11%) 5
• Stage 2: Reimplantation of new prosthesis after infection eradication

One-Stage Exchange

May be considered for select patients with: 6

• Known organism with favorable susceptibility profile
• Adequate bone stock
• Good soft tissue quality
• No immunocompromise
• Results in superior functional outcomes (mean Harris Hip Score 87.8 vs 75.5) and satisfaction scores (8.6 vs 6.9) compared to two-stage 6

Antimicrobial Therapy

Standard duration: 4

• 4-6 weeks of pathogen-specific intravenous therapy
• Followed by oral antimicrobials for total duration of 3 months for hip infections

For common pathogens (Staphylococcus aureus, which accounts for 26-40% of cases): 7

• IV options: Cefazolin, Vancomycin (for MRSA)
• Oral options: Cephalexin, appropriate anti-staphylococcal agents

For streptococcal infections (including Group B Streptococcus): 4

• IV: Penicillin G, Ceftriaxone, or Vancomycin
• Oral: Penicillin V, Amoxicillin, or Cephalexin
• Rifampin is NOT routinely recommended for streptococcal infections (unlike staphylococcal) 4

Duration considerations for virulent organisms: 5

• Gram-negative bacilli and group-D streptococci require ≥28 days of systemic antimicrobial therapy
• Shorter courses (<28 days) associated with significantly higher recurrence rates

Antimicrobial therapy alone without surgery is associated with higher treatment failure rates and should be reserved only for patients with significant comorbidities precluding surgery. 1

Special Considerations for Comorbidities

Diabetes and immunocompromise are recognized risk factors for prosthetic joint infection: 1, 3

• Inflammatory arthritis, immunosuppressant therapy, and wound complications increase infection risk 1
• The comorbidity burden of PJI patients has increased over time, presenting treatment challenges 7
• Immunocompromise is associated with treatment failure and may necessitate more aggressive surgical approach 8

Chronic Suppressive Therapy

If surgical options are exhausted or patient refuses further surgery: 4

• Consider chronic oral suppression with Penicillin V, Cephalexin, or Amoxicillin (organism-dependent)
• This is a salvage approach when definitive cure is not achievable

Critical Pitfalls to Avoid

Never assume post-operative joint pain and effusion represent normal inflammation without ruling out infection, especially with warning signs listed above. 2

Never rely on superficial wound swabs for microbiologic diagnosis—they are misleading and promote inappropriate broad-spectrum therapy. 1

Never proceed with reimplantation if cement was not completely removed at resection arthroplasty—this triples recurrence risk. 5

Never reimplant before 1 year interval in two-stage exchange unless compelling clinical reasons exist—early reimplantation quadruples recurrence risk. 5

Never use inadequate antimicrobial duration for virulent organisms (gram-negative, group-D streptococci)—minimum 28 days required. 5