Primary Total Hip Arthroplasty After Infection

1. Primary Total Hip Arthroplasty After Infection ICL 2001, Chapter 33 Robbins, MD; Masri, MD; Garbuz, MD; Duncan, MD Presented by Sepein Chiang, D.O. Garden City Hospital

2. Introduction • More than 200,000 THAs performed annually in the US • Small number performed after proven infection of the hip or proximal femur • Can produce severe early destruction of the hip joint • If treated early, may only need treatment much later in life for secondary degenerative changes

3. Introduction • Always be aware of the possibility of previous infection • Always treat previously “cured” bone and joint infections with skepticism • First recurrence may be delayed for decades • Gallie reported a case of femoral osteomyelitis in a 10 year old girl that first recurred after 80 years

4. Introduction • Type of infection: osteomyelitis or septic arthritis • Activity: active or quiescent • Time since infection: recent or historic • Organism: pyogenic, tuberculous or fungal • Treatment options

5. Osteomyelitis • In the western world, progressive reduction in prevalence • Early childhood: begins in the metaphysis and spreads to the femoral head causing osteonecrosis, septic arthritis and severe hip destruction • S. aureus most common (90%) • S. epidermidis, streptococci

6. Osteomyelitis • Most recurrences are apparent within the first year • 18% (119 of 655) recurrence • 66% occurred by 6 months • 82% by 1 year • 6% after more than 5 years • 50% had only one episode of recurrence • Proximal femur 12%, pelvis 5% Gillespie and Mayo, JBJS British, 1981

7. Septic Arthritis • 141 adult hips with septic arthritis • S. aureus in 77% • Gram negative organisms in 16% • Streptococci in 4% • H. influenzae peak incidence at age 2 years • Gram negatives more common in adults Kelly, Orthop Clin North Am, 1975

8. Septic Arthritis • Diagnosis may be difficult and delayed in infants • By-products of leukocytes and bacteria cause rapid cartilage erosions • Of all joints, infection of the hip is particularly incapacitating

9. Septic Arthritis • Osteonecrosis of the epiphysis • Trochanteric overgrowth or coxa magna • Bony or fibrous ankylosis • Acetabular dysplasia • Destruction of the proximal femur with dislocation • Adverse effects on future THAs

10. Tuberculous Infections • Prevalence of pulmonary TB has decreased • Prevalence of extrapulmonary TB has remained steady • 400 cases of skeletal TB per year in the US, of which 13% involved the hip • Mainly affects adults in the 5th and 6th decades • Immunosuppressed, malnourished • Increased reactivation rates in pts w/ HIV

11. Tuberculous Infections • Radiographically: destructive appearance with adjacent osteopenia and minimal sclerosis • May simulate pyogenic arthritis: periosteal reaction, sclerosis and sequestrum formation

12. Fungal Infections • Less joint destruction • Not always necessary to irrigate or debride the joint • Spontaneous infection of the natural hip joint is usually caused by noncandidal fungi • Candida is the only fungus reported to have caused infections at a THA • Usually associated with immunosuppression, IV therapy, drug abuse or direct inoculation

13. Risk Factors • IV drug abuse: 4X increase in infections of the hips, SI and sternocostal joints • Hemoglobinopathies: sickle-cell disease and Salmonella • Ongoing sources of infections • History of previous joint infection • Immunosuppression • Malnourishment

14. Exclusion of Active Infection: H&P • Fever • Discharging sinus • Rapidly increasing hip pain that has previously been infected

15. Exclusion of Active Infection: Hematologic Investigations • WBC: can often be normal • ESR: nonspecific • Transient elevation due to minor illness • Permanent elevation in chronic conditions such as connective tissue disorders • Cutoff of 30 mm/h has a sensitivity of 60% to 95% and specificity of 65% to 85%

16. Exclusion of Active Infection: Hematologic Investigations • CRP: acute phase protein • Sanzen: unless another probable cause was apparent, a CRP >20 mg/L indicated deep sepsis • Improved diagnostic accuracy by considering ESR and CRP together • Spangehl: all 35 of 202 THAs that were infected had an ESR >30 or a CRP >10 • Normal ESR and CRP effectively excluded infection • Elevation of both indicates an 83% probability of infection

17. Exclusion of Active Infection: Plain Radiographs • Chronic osteomyelitis: sclerosis with adjacent osteopenia, cortical thickening • Osteoarthritis secondary to a healed septic arthritis should evolve slowly with subchondral sclerosis and marginal osteophytes • Reactivation of infection: sudden clinical deterioration with rapid bone destruction

18. Exclusion of Active Infection: MRI • Active osteomyelitis: dark on T1, bright on T2 • With chronicity, the bright T2 marrow signal becomes more heterogeneous • 95% sensitivity • 88% specificity

19. Exclusion of Active Infection: Technetium Bone Scan • Very sensitive, nonspecific indicator of osteoblastic activity • Effectively treated chronic osteomyelitis may remain positive for over 1 year

20. Exclusion of Active Infection: Gallium Citrate Scanning • Taken up by leukocytes • Better indicator of infection than technetium alone • Often used sequentially with technetium • Less sensitive than technetium • Less specific than indium-labeled WBC scan

21. Exclusion of Active Infection: Indium-labeled WBC Scan • Merkel: More sensitive and specific than sequential technetium-gallium scan for low-grade musculoskeletal sepsis • Criticized in detecting chronic infections when PMNs were labeled • Improved when a third of the labeled leukocytes were lymphocytes • Decreased specificity where remodeling is occurring, such as in a degenerated hip

22. Exclusion of Active Infection: Aspiration Biopsy • Cherney and Amstutz: no growth on preimplantation aspiration of any of the 23% (7 of 31) of hips that had a recurrence of infection after THA • 86% sensitivity • 94% specificity • May perform multiple core needle biopsies for bacteriologic and histologic analysis

23. Exclusion of Active Infection: Mantoux Test • Suspected tuberculous infection • Intradermal skin test

24. Treatment Options • One or two stage reconstruction • Antibiotic cement • Girdlestone • Arthrodesis

25. Single Stage Reconstruction • Buchholz: 10 yr f/u on 583 pts • Antibiotic cement • 77% eradication • Raut: 7.5 yr f/u on 57 pts w/ actively draining sinuses • Gentamicin cement • 86% eradication

26. Two Stage Reconstruction • Garvin: reviewed 29 studies • 1 stage, no antibx cement: 58% cure • 2 stage, no antibx cement: 82% cure • 1 stage, antibx cement: 82% cure • 2 stage, antibx cement: 91% cure

27. Two Stage Reconstruction • Time interval from debridement to implantation: 6 wks to 6 months • McDonald: 5.5 yr f/u on 82 pts w/ cement without antibiotics • Reinfection rate was significantly higher when reimplantation was <1 year, 27% vs 7%

28. Antibiotic Cement • Addition of antibiotics to cement is unusual in North America • 57% of surgeons in the United Kingdom routinely add antibiotics to cement in primary cases • Masri found therapeutic levels of tobramycin in the periprosthetic fluid up to 4 months after implantation of antibx spacers

29. Antibiotic Cement • Streptomycin cement for active tuberculous osteomyelitis • Amphoteracin-B cement for fungal