RESUMO
BACKGROUND: Thanks to defense mechanisms, organisms have had to adapt themselves to an adverse natural setting that causes acute and chronic stress. This adaptive response that tries to protect the cells against lethal insults uses its own defense systems. MATERIAL AND METHODS: Prospective, observational, descriptive pilot study with analytic components to determine the baseline preoperative TNF levels of 35 patients undergoing total knee arthroplasty due to gonarthrosis. Ten patients with a diagnosis of infected total knee arthroplasty were also included. In order to find differences and possible associations, the Mann-Whitney U test or the Fisher test was used to compare the variables between the non-infected group of patients and the group with the infection complication. RESULTS: We found a statistically significant difference; higher levels of fibrinogen, erythrocyte sedimentation rate, C-reactive protein, TNF-alpha and temperature were found in the infected patients; temperature was not clinically relevant. CONCLUSIONS: In the absence of a diagnostic specificity, the combined determinations of acute phase reactants may be useful to detect the presence and intensity of the inflammatory and infectious processes.