Responsiveness of the Korean Version of the Michigan Hand Outcomes Questionnaire after Carpal Tunnel Release

BACKGROUND: The Korean version of the Michigan Hand Outcomes Questionnaire (K-MHQ) was recently validated; however, the questionnaire's responsiveness as well as the degree to which the instrument is sensitive to change has not been thoroughly evaluated in a specific condition in Koreans. We evaluated the responsiveness of the K-MHQ in a homogenous cohort of patients with carpal tunnel syndrome (CTS) and we compared it with that of the Korean version of the Disability of the Arm, Shoulder, and Hand Questionnaire (K-DASH), which was found to have a large degree of responsiveness after carpal tunnel release for Korean patients with CTS. METHODS: Thirty-seven patients with CTS prospectively completed the K-MHQ and the K-DASH before and 6 months after surgery. The responsiveness statistics were assessed for both the K-MHQ and the K-DASH by using the standardized response mean (SRM), which was defined as the mean change of the original scores after surgery divided by the standard deviation of the change. RESULTS: All domains of the K-MHQ significantly improved after carpal tunnel release (p < 0.001). The SRM for all scales but one (the aesthetics scale) showed large responsiveness of ≥ 0.8. The aesthetics scale showed medium responsiveness of 0.6. The combined function/symptom scale of the K-DASH significantly improved after surgery (p < 0.001). The SRM of the K-DASH revealed large responsiveness of 0.9. CONCLUSIONS: The K-MHQ was found to have a large degree of responsiveness after carpal tunnel release for Korean patients with CTS, which is comparable not only to the K-DASH, but also to the original version of the MHQ. The region-specific K-MHQ can be useful for outcomes research related to carpal tunnel surgery, especially for research comparing CTS with various other hand and wrist health conditions.