Utility of the iPhone 4 Gyroscope Application in the Measurement of Wrist Motion.

BACKGROUND: Measurement of wrist range of motion (ROM) is important to all aspects of treatment and rehabilitation of upper extremity conditions. Recently, gyroscopes have been used to measure ROM and may be more precise than manual evaluations. The purpose of this study was to evaluate the use of the iPhone gyroscope application and compare it with use of a goniometer, specifically evaluating its accuracy and ease of use. METHODS: A cross-sectional study evaluated adult Caucasian participants, with no evidence of wrist pathology. Wrist ROM measurements in 306 wrists using the 2 methods were compared. Demographic information was collected including age, sex, and occupation. Analysis included mixed models and Bland-Altman plots. RESULTS: Wrist motion was similar between the 2 methods. Technical difficulties were encountered with gyroscope use. Age was an independent predictor of ROM. CONCLUSIONS: Correct measurement of ROM is critical to guide, compare, and evaluate treatment and rehabilitation of the upper extremity. Inaccurate measurements could mislead the surgeon and harm patient adherence with therapy or surgeon instruction. An application used by the patient could improve adherence but needs to be reliable and easy to use. Evaluation is necessary before utilization of such an application. This study supports revision of the application on the iPhone to improve ease of use.

Comparison of Wrist Motion and Grip Strength in a Normal Chinese and Caucasian Population.

BACKGROUND: Anatomical and functional differences between Asian and Caucasian populations have been described and are important in treatment of wrist pathology. The purpose of this study was to establish and compare normal values in an Asian and Caucasian population. We hypothesized that a normal Asian population will have greater wrist ROM and reduced grip- strength when compared to a normal Caucasian population. METHODS: One hundred and-seventy-one normal Asian and 156 normal Caucasian wrists were evaluated. We excluded wrists with current or a history of wrist pathology including past surgery, injury or congenital malformation. We collected demographic information regarding occupation, body mass index (BMI), and previous wrist pathology. The wrist measurements included: wrist extension, flexion, radial, ulnar deviation, and grip strength. Wrists were also evaluated for a mid-carpal clunk, and scaphoid shift test. Mixed models accounted for evaluation of both hands in the same individual and for the relative contribution of different factors to the outcome measures of ROM and grip- strength. RESULTS: The two groups differed in height, BMI and the distribution of occupation. The Asian group had more flexion, less extension and similar radial/ulnar wrist deviation when compared to the Caucasian group. Ethnicity was a significant predictor of wrist joint flexion and extension significantly predicting grip- strength. Age was associated with ROM while occupation, hand side and gender were not significant factors in the mixed model. CONCLUSIONS: We found discrete differences between values in the two populations. More study of anatomical morphological patterns may explain the reason for variations in motion and grip- strength. The differences identified in this study between Asian and Caucasian populations should be taken into account when evaluating outcomes of wrist therapeutic procedures and rehabilitation in different communities.