Aims. Smoking is associated with post-operative complications but smokers often under-report the amount they smoke. Our objective was to determine whether a urine dipstick test could be used as a substitute for quantitative cotinine assays to determine smoking status in patients. Patients and Methods. Between September 2013 and July 2014 we conducted a prospective cohort study in which 127 consecutive patients undergoing a planned foot and ankle arthrodesis or osteotomy were included. Patients self-reported their smoking status and were classified as: ‘never smoked’ (61 patients), ‘ex-smoker’ (46 patients), or ‘current smoker’ (20 patients). Urine samples were analysed with cotinine assays and cotinine dipstick tests. Results. There was a high degree of concordance between dipstick and assay results (Kappa coefficient = 0.842, p < 0.001). Compared with the quantitative assay, the dipstick had a sensitivity of 88.9% and a specificity of 97.3%. Patients claiming to have stopped smoking just before surgery had the highest rate of disagreement between reported smoking status and urine testing. Conclusion. Urine cotinine dipstick testing is cheap, fast, reliable, and easy to use. It may be used in place of a quantitative assay as a screening tool for detecting patients who may be smoking. A positive test may be used as a trigger for further assessment and counselling. Cite this article: Bone Joint J 2016;98-B:1418–24

Whether patients with asymptomatic bacteriuria should be investigated and treated before elective hip and knee replacement is controversial, although it is a widespread practice. We conducted a prospective observational cohort study with urine analyses before surgery and three days post-operatively. Patients with symptomatic urinary infections or an indwelling catheter were excluded. Post-discharge surveillance included questionnaires to patients and general practitioners at three months. Among 510 patients (309 women and 201 men), with a median age of 69 years (16 to 97) undergoing lower limb joint replacements (290 hips and 220 knees), 182 (36%) had pre-operative asymptomatic bacteriuria, mostly due to Escherichia coli, and 181 (35%) had white cells in the urine. Most patients (95%) received a single intravenous peri-operative dose (1.5 g) of cefuroxime as prophylaxis. On the third post-operative day urinary analysis identified white cells in 99 samples (19%) and bacteriuria in 208 (41%). Pathogens in the cultures on the third post-operative day were different from those in the pre-operative samples in 260 patients (51%). Only 25 patients (5%) developed a symptomatic urinary infection during their stay or in a subsequent three-month follow-up period, and two thirds of organisms identified were unrelated to those found during the admission. All symptomatic infections were successfully treated with oral antibiotics with no perceived effect on the joint replacement.

We conclude that testing and treating asymptomatic urinary tract colonisation before joint replacement is unnecessary.

Cite this article: Bone Joint J 2014;96-B:390–4.