Validity and reliability of the Dexter Hand Evaluation and Therapy System in hand-injured patients

This study compares measurements obtained using the Dexter Hand Evaluation and Therapy System with those obtained using manual goniometers and grip and pinch dynamometers. Intrarater and inter-rater reliabilities for each tool were also examined. Repeated digit range of motion and strength measurements were performed on 30 subjects who had prior upper extremity injuries. Three therapists performed all measurements on each subject three times, using both Dexter and manual instruments. Analyses of variance (ANOVAs) and intraclass correlation coefficients (ICCs) were used to assess concurrent validity and therapist reliability. The findings show that the computerized Dexter finger goniometer and grip and pinch dynamometers provide measurements that are statistically similar to those of their manual counterparts. The ANOVA results for concurrent validity showed no significant differences between mean measurement values across therapists for the Dexter tools compared with the manual tools (p ≥ 0.54). In addition, no significant differences were found among or between the therapists' measurements. The range of ICCs for intrarater and inter-rater reliability for all four tests was 0.86 to 0.99. However, a two-way ANOVA revealed a therapist effect during pinch strength measurements (p ≤ 0.05), suggesting the need for same- therapist and same tool measurements until the Dexter pinch dynamometer has been further evaluated.