A brief screening tool for knee pain in primary care. 1. Validity and reliability

Objectives. To design and test the performance of a new knee pain screening tool (KNEST), both separately and together with a combination of existing questionnaires. which will be used to assess the general health status of k nee pain sufferers in primary care. Methods. A postal survey of knee pain and disability was sent to a random s ample of 240 individuals aged over 55 yr registered with two general practi ces in North Staffordshire. The survey questionnaire consisted of the KNEST ; a pain manikin; the Short Form 36 (SF-36): the Hospital Anxiety and Depre ssion Scale (HADS); demographic questions: and the Western Ontario and McMa ster Universities Osteoarthritis Index (WOMAC) for those who reported knee pain. A second, identical questionnaire was sent 2 weeks later to a tandem subsample of responders (n = 80) to test repeatability. Results. An 85% baseline response rate was achieved for the first questionn aire. The 12-month prevalence of knee pain identified from baseline respond ers to the survey was 45%. A response rate of 74% was achieved for the repe atability questionnaire. Each section of the questionnaire was well complet ed and repeatability was good for nearly all measures (most reliability sco res exceeded 0.6). A new core question about knee pain showed good internal reliability, with an agreement score of 91% between baseline and retest as sessment, and good construct validity in relation to knee pain identified o n the pain manikin (agreement 95%). Good agreement was found between recall ed consultation for knee pain in the questionnaire and evidence of consulta tion for knee pain in general practice records. Conclusions. The KNEST appears to be a reliable and valid composite tool fo r the study of population needs and outcomes of care for people aged over 5 5 yr with knee pain.