The AAOS guidelines recommend erythrocyte sedimentation rate and C-reactive protein testing for patients assessed for periprosthetic joint infection. For patients with abnormal ESR or CRP results, joint aspiration is recommended to obtain fluid for microbiological culture, cell count, and differential. Nuclear imaging is an option for diagnosis if infection has not been established and revision is not planned. Intraoperative Gram stain should not be used to rule out infection, but frozen sections of peri-implant tissues and multiple cultures during revision are recommended. Antibiotics should not be started before cultures in suspected periprosthetic joint infection cases. A study found the leukocyte esterase test to be highly sensitive and specific for diagnosing joint infection

1. AAOS GUIDELINES INFECTION
WORK-UP
 2.We recommend erythrocyte sedimentation rate and C-reactive
protein testing for
 patients assessed for periprosthetic joint infection.
 Strength of Recommendation: Strong
 3.We recommend joint aspiration of patients being assessed for
periprosthetic knee
 infections who have abnormal erythrocyte sedimentation rate
AND/OR C-reactive
 protein results.We recommend that the aspirated fluid be sent
for microbiologic
 culture, synovial fluid white blood cell count and differential.
 Strength of Recommendation: Strong

3. AAOS GUIDELINES FOR INFECTION
WORK-UP
 9. Nuclear imaging (Labeled leukocyte
imaging combined with bone or bone marrow
 imaging, FDG-PET imaging, Gallium imaging,
or labeled leukocyte imaging) is an
 option in patients in whom diagnosis of
periprosthetic joint infection has not been
 established and are not scheduled for
reoperation.
 Strength of Recommendation: Weak

4. AAOS GUIDELINES INFECTION
WORK-UP
 11.We recommend against the use of
intraoperative Gram stain to rule out
periprosthetic
 joint infection.
 Strength of Recommendation: Strong
 12.We recommend the use of frozen sections of
peri-implant tissues in patients who are
 undergoing reoperation for whom the diagnosis
of periprosthetic joint infection has not
 been established or excluded.
 Strength of Recommendation: Strong

5. AAOS GUIDELINES INFECTION
WORK-UP
 13.We recommend that multiple cultures be
obtained at the time of reoperation in patients
 being assessed for periprosthetic joint infection.
 Strength of Recommendation: Strong
 14. We recommend against initiating antibiotic
treatment in patients with suspected
 periprosthetic joint infection until after cultures
from the joint have been obtained.
 Strength of Recommendation: Strong

6. Leucocyte Esterase
 Scientific Articles | December 21, 2011
 Diagnosis of Periprosthetic Joint Infection:The
Utility of a SimpleYet Unappreciated Enzyme
 Javad Parvizi, MD, FRCS1; Christina Jacovides,
BS1;Valentin Antoci, MD, PhD1; Elie Ghanem,
MD1
 1 Rothman Institute of Orthopedics atThomas
Jefferson University Hospital, 925 Chestnut
Street, Philadelphia, PA 19107. E-mail address
for J. Parvizi: research@rothmaninstitute.com

7. Leukocyte Esterase
 Results: On the basis of clinical, serological, and operative
criteria, thirty of the 108 knees undergoing revision
arthroplasty were infected and seventy-eight were
uninfected.When only a ++ reading was considered
positive, the leukocyte esterase test was 80.6% sensitive
(95% confidence interval [CI], 61.9% to 91.9%) and 100%
specific (95%CI, 94.5% to 100.0%), with a positive
predictive value of 100% (95%CI, 83.4% to 100.0%) and a
negative predictive value of 93.3% (95% CI, 85.4% to
97.2%).The leukocyte esterase level correlated strongly
with the percentage of polymorphonuclear leukocytes (r =
0.7769) and total white blood-cell count (r = 0.5024) in the
aspirate as well as with the erythrocyte sedimentation rate
(r = 0.6188) and C-reactive protein level (r = 0.4719) in the
serum.

8. MOM HIP WORK UP
 GET XRAYS, EXAMINE PT
 LOOK FOR MECHANICAL FAILURE
 KNOW RECALLS(ASR, DUROM)
 LOOK FOR ABNORMAL ANTERVERSION OR
HIGHADB ANGLE
 MEASURE IONS(>5-7 PPb)
 REVISE IF PAINFUL
 DO MARS MRI OR ULTRASOUNDTO LOOK
FOR PSEUDOTUMORS