Construct validity of the AIMS-2 upper limb function scales as a measure of disability in individuals with osteoarthritis of the hand

This study aimed to validate the use of the Arthritis Impact Measurement Scales 2 (AIMS-2) Hand and Finger Function and Arm Function scales for assessing disability in persons with osteoarthritis (OA) of the hand. Ninety-nine subjects with hand OA completed the AIMS-2 scales, grip strength testing, and timed manipulation tasks. Confirmatory factor analyses determined that the ten items comprising the scales separated out into hand and arm limitations. Spearman correlations revealed the appropriate associations between Hand and Finger Function scale scores and grip strength (r = −0.37) and dexterity (r = 0.36). Arm Function scale scores discriminated individuals with additional upper limb involvement from those without (Mann–Whitney test, p < 0.01). Thus, convergent construct validity of the Hand and Finger Function scale and known-group validity of the Arm Function scale were shown. These AIMS-2 scales are valid and distinct measures of disability in individuals with hand OA.