Abstract
Aim
Autologous-labeled leukocytes combined with sulfur colloid bone marrow scan is the current imaging modality of choice for diagnosing prosthetic joint infection (PJI). Although this technique is reliable, in-vitro leukocyte labeling raises technical difficulties that limit its widespread use and sulfur colloid is increasingly difficult to obtain. Therefore, valid alternatives are needed. The purpose of our study was to determine the clinical value of 99mTc-sulesomab combined with 99mTc-colloidal rhenium sulphide (nanocolloid) bone marrow imaging in the diagnosis of infection in painful total joint arthroplasties.
Materials and methods
A retrospective study was conducted on a cohort of 53 patients with painful hip or knee prostheses that underwent 99mTc-sulesomab and 99mTc-nanocolloids sequentially, between January 2008 and December 2016. The combined images were interpreted as positive for infection when there was activity on the sulesomab scan without corresponding activity on the bone marrow scan. The final diagnosis was made with microbiological findings or by clinical follow up of at least 12 months.
Results
There were 49 total knee and 4 total hip replacements. Forty of them were women, with an average age of 65 years. Infections were diagnosed in 5 of the 53 patients. An isolated 99mTc-sulesomab scan shows 100% sensitivity but only 29.4% specificity. Combining it with a 99mTc-nanocolloid bone marrow scan, the overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 100%, 95.8%, 81.4%, 100% and 96.2% respectively.
Conclusion
99mTc-sulesomab combined with 99mTc-nanocolloid showed to be a useful method for diagnosing prosthetic joint infections. These technically simpler and ready-to-use products may be an alternative to autologous-labeled leukocytes/sulfur colloid marrow scan, although it needs validation at a larger scale.
