OBJECTIVES: :To evaluate everyday disability (in the broad sense of the term) due to knee arthritis in a population whose diagnosis has recently been confirmed. According to an epidemiological study conducted in France, the prevalence of symptomatic knee arthritis is estimated as 7.6%, about 2 million patients. METHODS: :Prospective, non-interventional evaluation. 100 French doctors (rheumatologists and GP) recruited patients who had consulted them spontaneously and for whom knee arthritis was diagnosed.The disability generated was evaluated by means of the BONe’S questionnaire. RESULTS: :456 subjects were deemed eligible for evaluation. The sex ratio favoured women (65%).The average age of the population was 65.16 ± 10.9 years. 35% declared that they were active.The average BMI of the population was 27.75 ± 4.9; the proportions for men and women were respectively: 27% and 34% < 25, 46% and 34% between 25 and 30, 21% and 32% > 30. The mean score of the burden was found to be 30.04 ± 17.8. The score differed according to sex: 31.33 ± 16.9 against 28.34 ± 18.9 (p < 0.05). The score also differed according to BMI: 26.1 ± 17.4 if < 25, 30.8 ± 18.1 between 25 and 30 and 33.6 ± 17 if > 30 (p < 0.01). The most affected dimensions were autonomy, leisure and psychology. The effect on the budget dimension was 6 times greater for active patients compared to inactive patients. The monthly expenses to be paid by the patient differed depending on the sex: €31.09 for women and €23 for men (not significant). CONCLUSIONS: : This evaluation confirms the impact of knee arthritis in the everyday life of subjects who suffer from it. 35% of subjects are active, and the negative impact on work is liable to grow in view of the ageing of the population and the longer working lives in developed countries.