We studied the correlation between change in the QuickDASH score and the absolute post-operative QuickDASH score with patient satisfaction after open carpal tunnel decompression. Threshold values in the QuickDASH score, the point at which the sensitivity and specificity are maximal in predicting patient satisfaction, were identified. During the study period, outcome data were compiled for 937 carpal tunnel decompressions, which included 219 (23%) male and 718 (77%) female patients with a mean age of 58 years (standard deviation (SD) 14). There was a significant improvement (mean difference 32, 95% confidence interval (CI) 30 to 34) in the QuickDASH from a mean of 54 (SD 20) to 22 (SD 23) at 1 year after surgery. There were 808 (86%) patients who defined their outcome as satisfactory at 1 year. The identified threshold values for the post-operative QuickDASH score (<=34 points) and the change (>=20 points) in the score were highly predictive of patient satisfaction. However, these threshold values varied significantly according to the baseline pre-operative score. The threshold values identified in the QuickDASH can be used to interpret the score. However, the influence of the pre-operative baseline score should be taken into account when comparing different cohorts of patients or using the values to power future studies.

Level of Evidence IV: Prognosis, observational cohort study