gms | German Medical Science

Objectives: Although there is a lack of information on the use of arthroscopy for the diagnosis of PPSI, it may be an additional tool to improve pre-revision diagnostics. The aim of the present study was to analyze the utility of arthroscopic biopsies for detection of periprosthetic infection in painful shoulder arthroplasty without evident signs of infection.

Methods: A retrospective analysis of all patients, who underwent a diagnostic arthroscopy for painful shoulder arthroplasty was performed. Arthroscopic tissue culture results were compared with the culture results of intraoperative tissue samples obtained at the time of open revision surgery. A minimum of 3 tissue samples from any area with suspicious appearance was collected. Cases with 2 or more positive cultures for the same microorganism obtained at open revision surgery were considered as true presence of infection.

Results and conclusion: Twenty-three cases in 22 patients were included in this study. Five of these 23 cases were classified as true infection based on the samples obtained during open revision surgery. Cutibacterium acnes was isolated in each case. Classifying any microbiological growth in the arthroscopic biopsies as positive resulted in a sensitivity of 100% and specificity of 39% for the detection of a periprosthetic shoulder infection (PPSI). If at least two positive samples with the same microbiological growth in the arthroscopic biopsies were considered as positive, sensitivity dropped to 80% but the specificity increased to 94.4%. Diagnostic arthroscopy is a reliable diagnostic tool in patients with suspicion but no clear evidence of PPSI. Arthroscopically obtained tissue biopsies for culture offer a high sensitivity and specificity in the diagnosis of PPSI if at least two cultures positive for the same microorganism are considered as infection.