Upper Extremity Disorders - Epidemiology and Measures of Disability

Abstract: The aim of this thesis was to investigate the prevalence and characteristics of long-lasting upper extremity symptoms in a general population and to study some methodological aspects of outcome assessment and reporting, including validation of a Swedish version of an upper extremity region-specific outcome instrument that potentially could be useful for assessing upper extremity disorders. A general health questionnaire was mailed to 3000 persons, randomly selected from a general population register; response rate 83%. The prevalence of long-lasting (> 6 months) upper extremity pain associated with activity limitations was estimated to 20.8%, and that of co-occurring long-lasting numbness/tingling was 6.7%. Of the participants 84% reported pain at more than one location. The second study aimed to introduce a Swedish version of the Disabilities of the Arm, Shoulder and Hand(DASH) outcome instrument and evaluate its reliability and validity. Following the process of translation and cultural adaptation the Swedish version of the DASH was found to be a reliable and valid instrument that can provide a standardized measure of patient-centered outcomes in upper extremity musculoskeletal conditions. In the third study, the quality of reporting and the outcome measures used in randomized clinical trials related to treatment of upper extremity disorders published in four orthopedic and hand surgical journals during 1992-2002 were assessed. Of the 92 articles assessed, only 40 (43%) described a randomization method that was judged to be appropriate indicating they were truly randomized. The outcome measures used were mainly on body function/structure level. The fourth study aimed to assess the longitudinal construct validity of the DASH. The DASH could detect and differentiate small and large changes of disability over time after surgery in patients with upper extremity musculoskeletal disorders. A 10-point difference in mean DASH score may be considered as a minimal important change. When a region-specific outcome instrument is used, combination with a generic instrument may be needed in the outcome assessment. Using an entire multi-scale generic instrument including scales that may not be relevant to the study purpose results in a lengthy questionnaire, increasing responder burden. Although selected scales have been commonly used, the reliability and validity of selective use of scales have not been studied. The aim of the fifth study was to assess the performance of health-status scales when used selectively or within multi-scale questionnaire. The use of selected scales about physical health from a multi-scale health-status questionnaire seemed to yield similar results compared to their use within the entire questionnaire.