Minimal clinically important difference of the Hand20 after carpal tunnel release and associated patient factors

Although carpal tunnel release is a widely performed treatment for carpal tunnel syndrome, postoperative functional recovery and satisfaction vary among patients. The Hand20 is a patient-reported outcome measure specifically designed to assess upper extremity function, but its minimal clinically important difference (MCID) remains undefined. This study aimed to estimate the MCID for the Hand20 in patients undergoing carpal tunnel release.

This retrospective study included 169 patients who underwent carpal tunnel release and completed the Hand20 preoperatively and 6 months postoperatively. The primary analysis employed an anchor-based approach using receiver operating characteristic curves, with Hand20 items for pain, daily living, and confidence serving as proxy anchors. Distribution-based methods (0.5 standard deviation [SD] and smallest detectable change [SDC]) were used for validation. Factors associated with MCID achievement were analyzed using multivariable logistic regression.

The mean Hand20 score improved from 70.9 preoperatively to 38.9 postoperatively. Anchor-based estimates ranged from 25 to 36 points. Sensitivity analyses using alternative thresholds demonstrated consistent findings across representative thresholds. By integrating these with distribution-based values (0.5 SD: 22.8; SDC: 30.97), 27 points was selected as the representative threshold. The overall responder rate was 48.5%. There were no significant differences in responder rates regarding surgical technique (endoscopic vs. open), age, or diabetes status. The preoperative Hand20 score was the only independent predictor of MCID achievement (OR 1.056, p < 0.001), indicating that patients with higher severity were more likely to achieve meaningful improvement.

The MCID for the Hand20 after carpal tunnel release is best interpreted as a range (approximately 27-36 points), with 27 points representing a pragmatic lower-bound estimate. This range provides a useful benchmark for determining treatment effectiveness from the patient's perspective. Approximately half of the patients achieved this meaningful improvement regardless of surgical technique or clinical background.