Minimal Clinically Important Difference After Carpal Tunnel Release Using the PROMIS Platform

In light of recently-proposed quality measures for carpal tunnel release (CTR), elucidating the minimal clinically important difference (MCID) for selected outcome measures will be important when interpreting treatment responses. Our purpose was to estimate the MCID of the Patient-Reported Outcomes Measurement Information System (PROMIS) instruments and the short Disabilities of the Arm, Shoulder, and Hand (QuickDASH) following CTR.

Adult patients undergoing isolated unilateral CTR between July 2014 and October 2016 were identified. Outcomes included the PROMIS Upper Extremity (UE) Computer Adaptive Test (CAT), Physical Function (PF) CAT, QuickDASH, and Pain Interference (PI) CAT. For inclusion, pretreatment baseline (within 60 days of surgery) and postoperative (6-90 days) UE or PF CAT scores were required, as well as a response on a 5-point Likert scale to the question "How much relief and/or improvement do you feel you have experienced as a result of your treatment?" The MCID was calculated using SD and minimum detectable change (MDC) distribution methods.

In response to the Likert scale question, 88.6% of patients reported improvement at a mean of 14.8 days after surgery. The infrequency of patients reporting no change (5 of 44; 11.4%) precluded calculation of a statistically sound anchor-based MCID value. The MCID values, as calculated using the one-half SD method, were 3.6, 4.6, 10.4, and 3.4 for the UE CAT, PF CAT, QuickDASH, and PI CAT, respectively.

We have calculated MCID values for the UE CAT, PF CAT, QuickDASH, and PI CAT for patients undergoing CTR. Although the small number of patients reporting no change and minimal change after surgery precluded an anchor-based MCID calculation, we report estimates using the one-half SD method for the MCID following CTR.

These MCID estimates will be helpful when interpreting CTR clinical outcomes and for powering prospective trials.