Purpose: The purpose of this study was to determine the usefulness of systematic bacteriological culture of drainage fluid after aseptic orthopaedic surgery in identifying infection early. There is much controversy over this point in the literature. In addition, the public health cost (approximately 30 euros per culture) must be considered in terms of effectivenes.
Material and methods: A prospective study was conducted in a single orthopaedic surgery department over a one-year period (1999) including all patients undergoing class I surgery (aseptic orthopaedic and traumatologic surgery). The population included 843 patients (52% men, 48% women, mean age 49 years, age range 15–98 years) who underwent 880 aseptic orthopaedic surgery procedures (osteosynthesis 60%, arthroplasty 30%, others 10%). One or several bacteriological cultures on early drainage fluid were performed (n=2434). The results of these cultures were analysed to determine their contribution to early detection of infection and rapid institution of adapted treatment (medical treatment with antibiotics or medical and surgical (revision) treatment).
Results: The bacteriological cultures were negative in 830 patients (98.5%) and positive in 13 (1.5%). A deep infection developed in 21 patients including 3 patients who had a positive drainage fluid culture and 18 who had a negative culture. In addition, ten patients had false positive cultures subsequent to extraneous contamination. The sensitivity, specificity and positive and negative predictive values were 14%, 98%, 23% and 98% respectively.
Discussion, conclusion: Drainage is a common procedure after orthopaedic surgery. The objective is to limit the risk of haematoma formation, but paradoxically with an increased risk of infection by retrograde contamination. The observed sensitivity and predictive values of drainage fluid cultures would suggest this is not a reliable method for detecting infection early, especially since the presence of a drain increases the risk of infection. In the final analysis, we do not recommend systematic culture of drainage fluid after aseptic orthopaedic surgery.
