Randomised controlled trials represent the gold standard in the evaluation of outcome of treatment. They are needed because differences between treatment effects have been minimised and observational studies may give a biased estimation of the outcome. However, conducting this kind of trial is challenging. Several methodological issues, including patient or surgeon preference, blinding, surgical standardisation, as well as external validity, have to be addressed in order to lower the risk of bias. Specific tools have been developed in order to take into account the specificity of evaluation of the literature on non-pharmacological intervention. A better knowledge of methodological issues will allow the orthopaedic surgeon to conduct more appropriate studies and to better appraise the limits of his intervention.

We tested prospectively for hepatitis C virus (HCV) in one orthopaedic surgeon's operative practice for one year. Of 425 consecutive patients, 19 (4.5%) were positive for HCV infection using a second-generation screening assay. The highest correlation with a positive test was the presence of tattoos and the second highest was intravenous drug abuse, but only after a second interview, since most patients did not report this risk on the initial questionnaire. Based on the criteria of the US Public Health Services algorithm, nine (47%) of the patients with a positive initial screening test or 2.2% of the 425 patients, had hepatitis C (both anti-HCV-positive and elevated alanine aminotransferase). In this group of nine, the presence of tattoos had the highest and intravenous drug abuse the second highest correlation, also after the second interview. There is no vaccine available for the prevention of HCV infection, and prophylactic immunoglobulin therapy has no proven value for primary exposure.

We report 16 orthopaedic patients who had antibiotic-associated diarrhoea (pseudomembranous colitis) after operation. There was an association with the use of cephradine and with the prolongation of prophylaxis for more than three peri-operative doses. Five cases occurred as a cluster, suggesting that the causative agent, Clostridium difficile, may be infectious in some situations.