Palmar abduction: reliability of 6 measurement methods in healthy adults.

PURPOSE: The aim of the current study was to assess reliability of 6 palmar thumb abduction measurement methods: conventional goniometry, the Inter Metacarpal Distance, the method described by the American Medical Association, the method described by the American Society of Hand Therapists, and 2 new methods: the Pollexograph-thumb and the Pollexograph-metacarpal. METHODS: An experienced hand therapist and a less-experienced examiner (trainee in plastic surgery) measured the right hands of 25 healthy subjects. Palmar abduction was measured both passively and actively. Means and ranges for palmar abduction were calculated, and intrarater and interrater reliability was expressed in intraclass correlation coefficients, standard errors of measurement, and smallest detectable differences. RESULTS: Mean active and passive angles measured with goniometry resembled values measured with the Pollexograph-thumb method (approximately 60 degrees). Mean angles found with the Pollexograph-metacarpal method were approximately 48 degrees. Mean active and passive distances for the Inter Metacarpal Distance were 64 mm. Mean active and passive distances found with the American Society of Hand Therapists method were 97 to 101 mm, and mean distances found with the American Medical Association method were 67 to 70 mm for active and passive measurements. Intraclass correlation coefficients for the Pollexograph-thumb, Pollexograph-metacarpal, and the Inter Metacarpal Distance indicated good and significantly higher intrarater agreement for active and passive measurements than intraclass correlation coefficients of conventional goniometry, the American Society of Hand Therapists method, and the American Medical Association method, which showed only moderate agreement. For interrater reliability, the same measurement methods were found to be most reliable: the Pollexograph-thumb, Pollexograph-metacarpal, and the Inter Metacarpal Distance. CONCLUSIONS: We found that the Pollexograph-thumb, Pollexograph-metacarpal, and the Inter Metacarpal Distance are the most reliable measurement methods for palmar abduction.