The Validity, Reliability, Responsiveness, and Bias of the Manchester-Modified Disability of the Arm, Shoulder, and Hand Score in Hand Injuries

The Manchester-Modified Disability of Arm, Shoulder and Hand questionnaire (M2 DASH) was developed by the authors as a modification to the original DASH questionnaire. In this study, we assessed the validity, reliability, responsiveness, and bias of the M2 DASH questionnaire for hand injuries using completed M2 DASH, Patient Evaluation Measure, and Michigan Hand Outcome questionnaires from 40 patients. The M2 DASH scores showed significant positive correlations with the Patient Evaluation Measure and Michigan Hand Outcome scores suggesting validity. There was also no evidence of a statistical difference in the M2 DASH scores when the condition had stabilized suggesting good test–retest reproducibility and reliability. The effect size and the standardized response mean for the M2 DASH score were greater than those for the Patient Evaluation Measure and Michigan Hand Outcome scores establishing that the M2 DASH is highly responsive. There was no gender, hand dominance, or dominant side injured bias for the M2 DASH score. There was, however, a relatively weak association between age and the M2 DASH score at presentation. We conclude that the M2 DASH questionnaire is a robust region-specific outcome measure. It is a valid and responsive questionnaire with test–retest reliability proven for hand injuries in this study. Gender, handedness, and side injured did not cause bias in the responses.