[Value of scintigraphy using labelled polynuclears in the diagnosis of infection of a joint prosthesis].

Fifty-three patients with suspected infection of prosthetic joints had Indium-111 granulocyte scintigraphy. Twenty-nine of them had associated technetium-99m phosphate scans. Labelled granulocyte sensitivity was 82% and specificity 100% for the group of 47 patients with suspected late infection. Technetium phosphate sensitivity was 92% and specificity 25%. The main quality of labelled granulocyte scintigraphy is its high specificity: there were no false positives in our series. Its main limitation seems to be that sensitivity is sometimes only moderate: we had 4 false negatives. The probable explanation is the histological characteristics of bone infection: vascular thromboses occur frequently and at an early stage, the inflammatory infiltrate is not very abundant and often has a low granulocyte content. The method is therefore reliable and can be used in situations where diagnosis of periprosthetic infection is difficult with conventional techniques.