[111 INDIUM LABELED LEUKOCYTE SCINTIGRAPHY IS A LOW SENSITIVITY TEST FOR DIAGNOSING PROSTHETIC JOINT INFECTION IN...

Nuclear medicine techniques are suggested to be used in equivocal cases only. Nuclear medicine procedures, specifically labeled leucocytes however, are widely used in the diagnosis of joint infection across Europe. The aim of our study was to determine if Indium 111 labeled leukocyte scintigraphy has a role in the diagnosis of infected prosthetic joints.

In this retrospective cohort study, the records of a total of 146 prosthetic hip or knee revision surgeries, in 116 patients, performed in our Institute between the years 2013-2016 were reviewed. A total of 34 patients with labeled leukocyte scans were analyzed. Ten patients had more than one scan (two to four times). The scintigraphy result reports were correlated with the outcome with respect to intra-/post-operative diagnosis of prosthetic joint infection.

The findings of 42 of 44 scintigraphy tests were negative. One study in a patient who had three prior negative labeled white blood cells (WBC) scintigraphies was equivocal. One study was positive, but a later test in the same patient was negative. Of these 34 patients, nine were demonstrated intra- or post operatively as positive for infected prosthetic joint, including the two positive cases above. The remaining 25 patients went through revision surgery with no evidence of infection; 30 of 38 bone scans were positive. Of these 30 patients, seven were demonstrated intra- or post-operatively as positive for infected prosthetic joint.

In our study population indium labeled leukocyte scintigraphy was found to be a non-sensitive test for the diagnosis of a prosthetic joint infection and had a poor negative predictive value. It is expected that following the guidelines more strictly and choosing the appropriate modality for assessing prosthetic joint infection will improve the diagnostic accuracy of these techniques.