- Culture Specimen:
- in the report by BR Levine and BG Evans, the authors studied 3 different intraoperative culture techniques and their diagnostic
value in determining clinical infection in patients after a total joint replacement;
- 24 patients (34 cases) met the selection criteria and were evaluated using intraoperatively collected tissue
samples, swab samples, and fluid samples injected into standard blood culture vials.
- they found that the use of fluid aspirate from intraoperative wounds immediately injected into blood culture vials
is a highly specific, sensitive, and accurate diagnostic culture technique (100%, 92%, and 94%, respectively);
- superiority of vial cultures is enhanced when organisms grown from the liquid media only are discounted as contaminants;
- ref: Use of Blood Culture Vial Specimens in Intraoperative Detection of Infection
Brett R. Levine, MS, MD; Brian G. Evans, MD. Clin Orthop 2001 January;2001(382):222-231
- Blood Work:
-
WBC:
- has uniformly been found to be of little value in the evaluation of the painful THR in the absence of fulminant sepsis;
- WBC is generally normal, but
ESR is usually elevated;
-
ESR
- useful in the dx of infection when there is no other reason for ESR elevation (such as RA or other types of inflammatory arthritis);
-
C-reactive protein: (may be more sensitive than ESR);
- 10 mg per liter is used as the threshold for infection;
- should return to normal values in 2-3 weeks;
- Hip Joint Culture: (see:
technique of hip aspiration)
- includes preoperative and intraoperative cultures;
- in difficult cases, consider obtaining multiple cultures;
-
preoperative aspiration:
- mainly indicated when history, ESR, CRP are equivocol for infection;
- 1/3 of cases, there are no clinical features to suggest infection, and diagnosis is made only on the basis of intraoperative cultures;
-
arthrogram can be performed following hip aspirate inorder to evaluate for loosening;
- be sure that lidocaine does not enter the joint (bacterostatic);
- multiple cultures should be taken if possible;
-
false negative results:
- sensitivity is generally greater than 90 %, if patients have not recieved antibiotics in the previous 2-3 weeks;
- it is not uncommon for a joint aspirate to exhibit no growth, even in face of sepsis, particularly from an organism of low virulence or if antibiotics have be given;
- note that in study by MM Tunney et al (JBJS Vol 80-B, 1999), authors note that some patients undergoing revision THA for perceived aseptic loosening,
may actually have low grade infection present on the biofilm surface of the implant, which may not appear on standard cultures;
- the authors note that using mild ultrasonication, bacteria were retrieved from 26 out of 120 implants, and in contrast, bacteria were cultured from only 5 patients
using routine microbiological techniques;
- the authors also noted that in 18/26 of these patients (cultures obtained from ultrasonification), there were significant inflammatory cells present;
- of these 26 patients w/ positive cultures, infection was suspected in only 6;
- propionibacterium acnes was cultured in 12 samples (and cultured in another 4 samples along with another organism);
- the authors note that infection with low virulence organisms with propionibacterium and staph epi often cause delayed infections with a long interval
between inoculation of the bacteria and the onset of symptoms (which may explain why these implants are classified as aseptically loose);
-
false positive:
- may be as high as 13% in THR patients, but is generally less than 5% (ie specificity is about 96%);
- as pointed out by Lachiewicz et al 1996, false positives can be reduced if cultures which only grow in liquid medium are considered contaminants (unless
there is growth of an anaerobic strain of bacteria);
- references:
- The value of aspiration of the hip joint before revision total hip arthroplasty. R Barrack and W. Harris. JBJS. Vol 75-A. 1993. p 66-76.
-
Failed total hip replacement: assessment by plain radiographs, arthrograms, and aspiration of the hip joint.
-
bacteriology:
-
staph aureus and staph epidermidis are the most commonly found organisms;
- the above two bacterial species along with pseudomonas are slime producers (glycocalyx) which makes them particularly resistant to treatment w/ antibiotics;
- gram negative organisms which do not produce a glycocalyx may not be as virulent as previously thought;
- consider need for Ziehl Nielsen stains, mycobacterial cultures, and fungal cultures;
- references:
-
Methicillin-resistant Staphylococcus epidermidis in infection of hip arthroplasties.
- Deep infection of cemented total hip arthroplasties caused by coagulase negative staphylococci. PG Hope et al. JBJS. Vol 71-B.(5) p 851-855. 1989.
- Frozen Section Histology:
Treatment of Infection at the Site of Total Hip Replacement. EL Masterson et al. JBJS. Vol 79-A. No 11. Nov 1997. p 1740.
Treatment of the septic hip with total hip arthroplasty.
Total Arthroplasty and the Veterans Administration--Symposium: Total Hip Arthroplasty: Infections at the Site of a Hip Implant Successful and Unsuccessful Management.
Why use drains
Comparative study of skin closure in hip surgery.
Deep-wound infection after total hip replacement under contemporary aseptic conditions.
Infections at the site of a hip implant. Successful and unsuccessful management.
The efficacy of suction drains after routine total joint arthroplasty.
Perioperative factors associated with septic arthritis after arthroplasty. Prospective multicenter study of 362 knee and 2,651 hip operations.
Pathobiology of infection in prosthetic devices.
The Use of Porous Prostheses in Delayed Reconstruction of Total Hip Replacements That Have Failed Because of Infection.
Infection after Total Hip Arthroplasty. A Study of the Treatment of 106 Infections.
D.T. Tsukayama MD and R.B. Gustilo MD JBJS Vol 78-A, No. 4. Apr 1996. p512.
Acute and subacute deep infection after uncemented total hip replacement using antibacterial prophylaxis.
Charnley low friction arthroplasty in tuberculosis of the hip. An eight to 13-year follow-up.
Improved detection of infection in hip replacements. A currently underestimated problem.
MM Tunney et al. JBJS. Vol 80-B. No 4. July 1998. p 568.
The value of hip aspiration versus tissue biopsy in diagnosing infection before exchange hip arthroplasty surgery.
Accuracy of joint aspiration for the preoperative diagnosis of infection in total hip arthroplasty.
