Reliability of the iPad Measurement for Range of Dart-Throwing Motion

Abstract

Hypothesis: The dart-throwing motion (DTM) is functionally very important movement from radial extension to ulnar flection of the wrist and the anatomical and biomechanical futures have been demonstrated experimentally. Clinically, there is the only report to be published to describe the method of goniometric measurement for DTM but the reliability of measurement has not been evaluated. We hypothesized that our DTM measurement method using a tablet device and a simple jig can be a more reliable method. Methods: Participants were 10 healthy volunteers for assessing intrarater reliability and 3 examiners for interrater reliability. Range of extension-flexion and DTM were evaluated. Participants moved their wrist in each motion plane on a flat table. During the DTM measurements, their hand was fixed to an isosceles right triangle jig and kept their wrist rotation 45° obliquely on the table, so they moved their wrist freely in a DTM plane on the table. Photo images at each maximum wrist position from right overhead were recorded using a tablet device and the angle was measured by goniometric software launched on the device. Reference points were marked on participant’s skin before recording images according to our protocol. Intraclass correlation coefficients (ICC) were compared to determine intrarater and interrater reliability, using the SPSS software package ( P < .05). Results: All results are shown in Table 1. According to the guideline provided by Landis and Koch, there was substantial intraobserver (ICC = .67, .71) and interobserver (ICC = .77, .72) in flexion and extension, respectively. We observed almost perfect intraobserver (ICC = .92) and substantial interobserver (ICC = .79) in ulnar flexion and substantial intraobserver (ICC = .62) in radial extension in a DTM plane. There was moderate interobserver (ICC = .59) in radial extension in a DTM plane. Conclusion: The results of the study indicate that the measuring method of the range of motion by use of tablet device can maintain fixed reliability or more. Intrarater and interrater reliability of our method of measurement for DTM compares favorably with conventional flexion-extension motion. The recording of photo image can transform a 3-dimensional object to the plane figure and make the measurement easy.