[Staged diagnosis of septic hip endoprosthesis loosening with laboratory parameters and antigranulocyte scintigraphy]

The value of serial diagnosis of septic loosening of hip endoprosthesis using laboratory parameters and antigranulocytes scintigraphy was investigated and compared to joint aspiration.

In 35 patients with intraoperative verification of infection, we calculated sensitivity, specify and prevalence dependent positive and negative predictive values for antigranulocyte scintigraphy, laboratory tests and the most suitable combination of both. We also calculated predictive values of joint aspiration using sensitivity and specify values given in the literature.

From negative and positive predictive values, of the sedimetation rate and leukocyte count provided no increase of information. We found the same result for positive predictive values of C-reactive protein. For antigranulocyte scintigraphy alone, we found a distinct but still unsatisfying increase of information. Nevertheless, in both cases infection could be excluded definitely. Therefore, the combination of C-reactive protein and antigranulocyte scintigraphy was suitable and the positive predictive values of this combination were only about 5% lower than those of joint aspiration. But with joint aspiration, infection could not be excluded.

A positive result in serial diagnosis using C-reactive protein and antigranulocyte scintigraphy leads to an distinct increase in the probability of infection which is comparable to that of joint aspiration. The additional advantages of this procedure are the certain exclusion of infection and the absence of invasiveness.