[Histopathologic diagnosis of infectious loosening of joint prostheses]

To optimize the reliability of histopathological criteria for periprosthetic infection, 110 tissue specimens from joint prostheses were analyzed with quantification of the inflammatory cells and immunohistochemical typing of lymphocytes and plasma cells. As reported in the literature the density of granulocytic infiltration was the most sensitive marker of periprosthetic infection with an accuracy of 84%, a sensitivity of 91%, a specificity of 81%, a positive predictive value of 67%, and a negative predictive value of 95%, using the mostly favored limit value of 5 granulocytes per HPF. T lymphocytes were also found to a high degree in cases of aseptic loosening. In contrast, B lymphocytes were predominantly seen in cases with periprosthetic infection. For B lymphocytes an accuracy of 80% and a sensitivity of 79% were calculated and for plasma cells an accuracy of 75% and a sensitivity of 79%. Our data suggest that the quantification of granulocyte, B-cell, and plasma cell infiltrates is an important parameter for verifying the diagnosis of periprosthetic infection.