Computerized Measurement on Angular Parameters for Hallux Valgus: Comparison of 100% and 150% Magnified Digital Radiography

Sung, Il Hoon; Lee, Doo Yeon; Sung, Chang Ho; Seo, Woo Young

Abstract

PURPOSE
To study computerized measurements of angular parameters on 100% and 150% resized digital radiography of hallux valgus deformity.
MATERIALS AND METHODS
30 digital radiography of standing foot anteroposterior view of hallux valgus patients were included. Two observers(A, B) independently measured hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) in two times on both 100%-size and 150% magnified images respectively, using computerized measurement software tools. The results were interpreted with the statistical software program, Statistical Analysis System, version 9.2.
RESULTS
In repeated measurements of each observer, measurements on 150% magnified image showed no differences of all three parameters and with 100%-size image, there were differences of HVA (observer A) and 1-2 IMA (observer B) (p>0.05). When testing interobserver reliability, both observers showed differences in measurement of HVA and DMAA (p<0.05), but no differences in measurement of 1-2 IMA in both images. Within the 95% confidence interval, limits of error of measurements between two observers on HVA, IMA and DMAA were 2.7degrees 1.4degrees and 5.0degrees respectively in 100%-size images, and 2.6degrees, 1.6degrees and 4.7degrees respectively in 150% magnified images.
CONCLUSION
In computerized measurements for angular parameters of hallux valgus with digital radiography, 150% magnified images showed intraobserver reliability. Both 100% and 150% magnified images failed to show interobserver reliability. Measurement of 1-2 IMA in both 100% and 150% images showed less interobserver error.