Intrarater and interrater reliability of a hand-held dynamometric technique to quantify palmar thumb abduction strength in individuals with and without carpal tunnel syndrome.

STUDY DESIGN: Clinical measurement.

INTRODUCTION: Individuals with carpal tunnel syndrome (CTS) sometimes exhibit weakness of palmar abduction strength (TAS). Reliable assessment of this strength in both subjects with and without CTS with the commonly available Microfet 2 is not known.

PURPOSE OF THE STUDY: The purpose of this study was to determine the intrarater and interrater reliabilities of a handheld dynamometric (HHD) method to assess TAS in individuals with and without CTS using the commercially available MicroFET2 and to examine the association between TAS in individuals with CTS and the Carpal Tunnel Symptom Questionnaire (CTSQ) scores.

METHODS: In 2 different study phases, individuals with and without CTS were assessed for TAS by 2 different examiners. The CTSQ was administered to the individuals with CTS.

RESULTS: Intrarater and interrater reliability coefficients (0.89-0.93 and 0.82-0.90, respectively) were excellent in individuals with and without CTS. Weak negative correlations were found between TAS and overall CTSQ and symptom severity subscale scores, and a moderate negative correlation was found between TAS and functional Status Subscale score.

DISCUSSION: This HHD method of reliably assessing TAS better quantifies deficits and progress than traditional manual muscle testing for muscle grades greater than 3/5.

CONCLUSION: This method of HHD reliably quantifies TAS but is more reliable with the same than different raters.