Assessing the clinical significance of change scores following carpal tunnel surgery

This article presents a prospective longitudinal study to determine the cut-off values for change scores of DASH, Levine, and Kamath questionnaires to distinguish clinical improvement following carpal tunnel surgery. Fifty-four patients (40 female, 14 male), with positive nerve conduction studies, were prospectively followed up. Three questionnaires (DASH, Levine, and Kamath) were posted to patients at four and two weeks prior to their operation and then six weeks following surgery. A patient global impression of change (PGIC) score was completed for patients to rate the overall change in their symptoms. According to the PGIC, 93% of patients improved. The cut-off values for raw change scores that best define clinically significant improvement following carpal tunnel release were 20.9 for DASH, 0.47 for Levine, and 1.97 for the Kamath questionnaire. This study provides a methodological framework for identifying clinically significant changes following treatment. A questionnaire follow-up of patients is now possible using the data provided.