The Measure of Activity Performance of the hand (MAP-Hand) - A reliable and valid questionnaire for use in patients with hand osteoarthritis with specific involvement of the thumb

b Study Design Cross-sectional methodological study with test-retest design. Introduction The Measure of Activity Performance of the Hand (MAP-Hand) is an assessment tool measuring hand-related activity limitations. Purpose To assess reliability, validity, and interpretability of the MAP-Hand in patients with hand osteoarthritis with specific involvement of the thumb (CMC1). Methods One hundred-and-eighty patients referred to surgical consultation for hand osteoarthritis affecting the CMC1 were included in the evaluation of validity and interpretability. Among these, 59 stable patients were included in reliability analyses, completing the questionnaire twice with a 2-week retest interval. The MAP-Hand has 18 predefined and 5 optional patient-specific items, scored on a 4-point scale (1 = no difficulty to 4 = not able to do). Relative (ICC2.1) and absolute (SDC95%ind) reliability were calculated. An ICC of >0.70 was considered acceptable. Nine (75%) or more of 12 predetermined hypotheses had to be confirmed for acceptable construct validity. Interpretability was assessed using floor and ceiling effects and considered present if 15% scored at eitherend of the scale. Results Mean (SD) age was 63 (8) years, and most patients were women (79%). The mean total score of predefined items showed acceptable reliability (ICC2.1 0.74, SDC95%ind 0.60) and construct validity. The mean total score of the patient-specific items did not reach acceptable reliability. Ceiling effect was found for the predefined items. Discussion and Conclusions We found that the mean total score of the predefined items on MAP-Hand had acceptable reliability and construct validity but a ceiling effect in patients with hand osteoarthritis with CMC1 affection.