10. Risk factors
Surgical technique
Prophylactic antibiotic
Single most effective method of ↓ infection
1st gen. cephalosporin
Allergy vancomycin / clindamycin
30-60 min before incision
(peak serum bone conc. within 20 min)
Repeat every 4 hrs & bleed >1,000 ml
Discontinue 24 hrs after surgery
13. Risk factors
Post operative management
• Bacteremia: oral > GI > GU procedure
• Avoid in first 3-6 mo (high incidence)
AAOS & ADA 1997
• First 2 yrs, specific risk factor for all pts ATB prophylaxis
• After 2 yrs consider in high risk pts
Recommended regimens (before procedure 1 hr)
• Cephalexin, cephradine, amoxicillin 2 g. oral
• Cephalosporin 1 g / ampicillin 2 gm IV / IM
• Clindamycin 600 mg oral (allergy to penicillin)
• Clindamycin 600 mg IV / IM (allergy to penicillin)
Advisory statement. J Am Dent Assoc, 1997
14. Potential risks of hematojenous
total joint infection
• All patients for the first 2 years after joint replacement
• lmmunocompromised / immunosuppressed patients
- Inflammatory arthropathies
- Drug-induced immunosuppression
- Rheumatoid arthritis
- Radiation-induced immunosuppression
- Systemic lupus erythematosus
• Patients with comorbidity conditions
- Previous prosthetic joint infections - HIV infection
- Poor nutrition
- Insulin-dependent diabetes
- Hemophilia
- Malignancy
Advisory statement. J Am Dent Assoc, 1997
18. Microbiology
• Methicillin-resistant organism vancomycin
Ries MD, J Arthroplasty, 2001
• Rifampicin = good biofilm & tissue penetration
improve success when use ĉ other synergistic agent
Zimmerli W, JAMA, 1998
19. Differential diagnosis
A painful knee is infected until proved otherwise
Insall, 1981
•
•
•
•
Periprosthetic fx
PF problem
Aseptic loosening
Soft tissue disruption
•
•
•
•
Instability
RSD
HO
Arthrofibrosis
20. Diagnosis
Fundamental of diagnosis
* * * High index of suspicion * * *
Clinical history Physical examination Radiography Aspiration Hematologic
studies
Radionuclide studies
Pathology
21. Diagnosis
History
• Pain = most common presenting symptom
• Typical = rest / night / persistent / progressive pain
• Progressive stiffness
• Hx of prolong postop drainage, ATB treatment
Physical examination
• Swelling, effusion, warmth, erythema, tenderness
• Painful range of motion
• Persistent wound drainage
strongly suggestion early aggressive Rx
22. Diagnosis
• Swab wound not recommend
• Empirical ABO for wound drainage mask symptoms,
affect subsequent C/S, predispose for drug resistant
• Diagnosis in early postop period
– ESR, CRP limit value
– Typically by arthrocentesis
23. Aspiration
• Leucocyte count & differentiation
• Gram strain (sens 97%, spec 26%) (
• Culture for aerobic & anarobic bacteria
>1,700/ml3, PMN > 65% (sens 94-97%, spec 88-98%)
Trampuz A, Am J Med, 2004
• Ongoing ATB stop for several wks before aspiration
24. Mark Coventry Award Paper
Diagnosis of early post-operative infection following TKA:
The utility of synovial fluid cell count and differential
“Synovial WBC count is an excellent test for diagnosing
infection within 6 wks after 1oTKA
with an optimal cut-off 27,800 cells/mm3 and 89% PMN”
Sens 84%, spec 99%, PPV 94%, NPV 98%
Craig J. Della Valle
Presented at the Knee Society Specialty Day Meeting
March 13, 2010, New Orleans
26. Guideline for ESR & CRP
1. Normal ESR & CRP reliable for the absence of infection
2. CRP more useful than ESR for monitoring
3. Use with other tests for the diagnosis of infection
Spangehl MJ, JBJS, 1999
31. Intraoperative tissue frozen section
• Widely use
• Result depend on
Adequate & representative tissue obtaining
Accurate interpretation by skilled pathologist
> 5 PMN/HPF at least 5 fields Sens 100%, spec 96%
>10 PMN/HPF at least 5 fields Sens 25%, spec 98%
Feldman DS, JBJS, 1995
Della Valle CJ, JBJS 1999
32. Intraoperative tissue frozen section
Reliable predictor for infection
• >10 PMN/HPF: sens 84%, spec 99%, PPV 89%, NPV 98%
• 5-10 PMN/HPF: need other test to differentiate
• <5 PMN/HPF: infection was highly unlikely
Lonner Jh et al, JBJS,1996
35. Definite diagnosis
At least one of the following
1. Same organism from c/s ≥ 2 specimens by aspiration /
deep tissue from surgery
2. Intraarticular tissue histopathology = acute inflammation
3. Gross purulence at the time of surgery
4. Actively discharging sinus tract
Hansen, CORR, 1994
36. Definite diagnosis
At least one of the following
1. Open wound / sinus tract communicate ĉ joint
2. Systemic signs / symptoms ĉ pain & purulent fluid
3. At least 3 of 5
ESR > 30 mm/hr
CRP >10 mg/L
Frozen section > 5 PMN/HPF
Preoperative aspiration c/s ≥ 1 +ve
Intraoperative c/s ≥ 1 +ve
Spangehl MJ, JBJS, 1999
37.
38. Segawa &Tsukayama classification
“Classify on the basis of clinical presentation”
Type1
Timing
Definition
Type2
Type3
Type4
Positive
intraop C/S
Early
postoperative
infection
Acute
hematogenous
infection
Late (chronic)
infection
Same
Occurring within
organism
first month after
≥2 from C/S
surgery
Hematogenous
Chronic
seeding of
indolent
previously
clinical course;
well-functioning
present >1
prosthesis
month
* * * Guide to treatment * * *