[Patient-centered evaluation of illness outcome in musculoskeletal diseases: model of illness sequelae and definition of the concept].

Musculoskeletal conditions usually cause pain, physical, psychological and social disability, and consequently reduce a patient's quality of life. Nowadays, it is generally accepted that patients are truly capable to assess disease consequences, if they are questioned with appropriate instruments. Models of disease and the disabling process provide the conceptual background for the measurement of disease consequences. To date, standardized assessment of outcomes with psychometrically sound instruments is commonplace in clinical trials, clinical epidemiology, economic studies, and health services research. However, standardized assessment tools are not yet widely used in clinical practice.