The value of suction drainage fluid culture during aseptic and septic orthopedic surgery: A prospective study of 901 patients

There are no guidelines on the value of suction drainage fluid culture (SDC ), and it is difficult to determine whether the organisms cultured from suc tion drainage fluid samples are pathogenic or simply contaminants. We perfo rmed 2989 cultures of suction drainage fluid samples obtained, during a 1-y ear period, from 901 patients who underwent aseptic or septic orthopedic su rgery (946 operations). The culture results were analyzed to evaluate their ability to detect postoperative infection after aseptic operations or to d etect either a persistent or new episode of sepsis in patients known to hav e infection. For aseptic operations, the sensitivity of SDC was 25%, the sp ecificity was 99%, the positive predictive value was 25%, and the negative predictive value was 99%. For septic operations, the sensitivity of SDC was 81%, the specificity was 96%, the positive predictive value was 87%, and t he negative predictive value was 94%. We conclude that, for aseptic orthope dic surgery, SDC is not useful in detecting postoperative infection. Howeve r, for septic orthopedic surgery, it is of clinical importance.