Nuclear imaging

The information presented throughout this guideline shows that there is no single preoperative investigation that can reliably diagnose an infection. Diagnosis usually depends on the combined use of numerous tests. Recognizing subclinical infections before revision surgery is, therefore, a major concern.

Patients in whom diagnosis of infection has not been established includes patients with a higher probability of infection who have abnormal ESR and/or CRP levels, but whose aspiration results are inconclusive (i.e., fluid cannot be obtained from the joint or culture and cell count results disagree).

The studies included for this recommendation, while of Level I and Level II quality, were not specific to patients not scheduled for reoperation, so the work group downgraded the strength of the recommendation from moderate to limited.

In addition, imaging studies may require special expertise and consultation with the imaging provider.

Technetium-99- or Indium-111-labeled-Leukocyte Imaging

Four included studies indicated that a Tc-99-labeled white blood cell scan was possibly a useful “rule in” test (range of positive LR:1.4-22),^{35, 93, 97, 101} while five included In-111 studies indicated that it was possibly useful as both a “rule in” and “rule out” test (range of positive LR: 2-14; range of negative LR: 0.03-0.63).^{35, 46, 63, 85, 87}

Combined labeled-Leukocyte/Bone Imaging

Three included studies of combined Tc-99 bone scans and In-111 white blood cell scans also indicated the possible utility of these tests for confirming and excluding infection (range of positive LR:3-18, range of negative LR: 0.12- 0.47).^{46, 95, 102} One study of combined Tc-99 bone scans and Tc-99 white blood cell scans produced similar results (positive LR: 6, negative LR: 0.44).⁸⁴

Combined labeled-Leukocyte/Bone Marrow Imaging

The four included studies of combined leukocyte/bone marrow imaging indicated that the test may be a good “rule in” and “rule out” test, but the results varied between studies (range of positive LR: 9.8-45, range of negative LR: 0.02- 0.34).^{47, 60, 67, 97}

Gallium-67 Imaging

Two included studies indicated that it may be a good “rule in” test but the ability of this test to rule out infection was unclear (range of positive LR: 24-111, range of negative LR: 0.07-0.62).^{55, 88}

FDG-PET Imaging

Three included studies of FDG-PET imaging indicated that the test is possibly good at both ruling in and ruling out infection but, again, the results varied between studies (range of positive LR: 11-19; range of negative LR: 0.16-0.66).^{15, 20, 60}

Technetium-99m Bone Imaging

The three included studies of triple-phase Tc-99m bone scintigraphy varied in their estimates of the test’s diagnostic efficacy, limiting the ability to determine whether the test is effective at either confirming or excluding infection (range of positive LR: 2-8, range of negative LR: 0.1-0.8).^{9, 58, 73} One included study of two-phase Tc-99m bone scintigraphy provided no evidence of diagnostic efficacy (positive LR: 1.0, negative LR: 1.7).⁹⁷ Based on these studies, triple-phase Tc-99m bone imaging may be possibly useful; however, there is no consistent evidence of diagnostic benefit. Therefore more study is needed.

Computed Tomography (CT) and Magnetic Resonance Imaging, MRI

Please refer to Recommendation 10 for information concerning these modalities.