Orthopedic wound infections. 182 cases after 8913 operations during an 8-year survey

We performed a surveillance of postoperative wound infections at our department for a period of 8 years. The surveillance was based on forms completed by the surgeons at the department. Retrospectively, by scrutinizing the records of patients with recorded infections, the criteria for infections used by the surgeons were compared with the criteria recommended by the Centers for Disease Control, USA, for routine infection surveillance studies: 1) pus present in the wound, 2) bacteria isolated from the wound, 3) spontaneous wound breakdown or surgical intervention due to suspected infection; if culture is performed, it must be positive, 4) evidence of infection at reoperation or at radiologic or histopathologic examination (restricted to deep infections) or 5) diagnosis of infection by a surgeon. 182 infections were recorded; in 106 (58%) pus was present, drained either spontaneously or by surgical intervention, in 24 (13%) no pus was seen, but the culture was positive. In 116 cases, surgical intervention was performed or wounds spontaneously broke down; pus was found in 101 of these and culture of non-purulent material was positive in 13 and negative in 2. In 52 (29%) patients, only criterion 5 was fulfilled. In surveillance studies where the recordings are based on several observers, the subjective criterion 5 may, as in our study, give a falsely high number of infections, also preventing comparison between studies. We recommend that all suspected infections are cultured and that only criteria 1, 2 and 4 are used.