VALUE OF LEUKOCYTE SCINTIGRAPHY IN SUSPEC TED IMPLANT INFECTION IN PATIENTS WITH RHEUMATOID-ARTHRITIS

When infection of implants is suspected, optimal management requires a ccurate confirmation or exclusion of infection. However, in spite of d emonstrative clinical signs cultures of smears or chemical parameters of inflammation frequently are ambiguous. Scintigraphy with indium-lab eled white blood cells (WBC) has been reported to be sensitive and spe cific in the diagnosis of low-grade sepsis of the musculoskeletal syst em. Twenty-eight patients with possible infection were prospectively s tudied. Infection was suspected in 19 cases with total hip joint prost hesis, 14 cases with knee joint prosthesis and 1 case with shoulder jo int prosthesis. All of them underwent scanning with indium-111-labeled WBC and subsequently underwent surgery. At surgery infections were de termined by means of culture or histologic results. When correlated wi th culture and histologic results sensitivity of 111-indium-WBC imagin g was 89 %, with a specifity of 67 % and a predictive accuracy of 77 % . In patients with rheumatoid arthritis, however, predictive accuracy of 111-indium-labeled WBC imaging was higher than with standard diagno stic methods. The difference was statistically significant (P < 0.05, chi(2)-test). In the patients examined as a whole, predictive accuracy of 111-indium-labeled WBC imaging does not differ from that of standa rd diagnostic methods. That is why expensive and time-consuming 111-in dium-WBC imaging is not justified generally in diagnosis of infection of implants. 111-Indium-WBC imaging is well suit ed to supplement stan dard diagnostic methods in patients with rheumatoid arthritis.