A novel rapid measurement of hallux valgus parameters using the built-in photo edit function of smartphones

Xiaoji Luo,Chao Lu,Tianji Huang,Lin Wang,Weiyang Zhong,Zenghui Zhao

doi:10.1186/s12891-021-04604-y

Abstract

ObjectiveThe objective of this study was to assess the accuracy and reliability of and time taken by a novel method using the built-in photo-edit function of smartphones compared with PACS in measuring hallux valgus parameters.MethodsSeventy patients (124 ft) admitted to our hospital with a diagnosis of hallux valgus without previous surgical procedures were retrospectively reviewed. The foot radiographs of all the patients were extracted from PACS. The hallux valgus angle (HVA) and the first and second intermetatarsal angles (IMAs) were measured by PACS and by this novel method using the built-in photo-edit function of a smartphone. The results of these two methods were compared, and the accuracy and reliability were assessed between these two methods.ResultsThe average parameters measured by PACS were as follows: HVA average: 37.43 ± 9.61°; IMA average: 13.37 ± 4.01°. The average parameters measured by smartphones were as follows: HVA average: 37.09 ± 9.52° and IMA average: 13.49 ± 3.91°. When compared by the independent-samples T test, the average parameters between PACS and smartphones were not significantly different (HVA PACS vs HVA smartphones: P = 0.776; IMA PACS vs IMA smartphones: P = 0.816). The variability of the HVA (F = 0.166, P = 0.992) and IMA (F = 0.215, P = 0.982) measurements was similar for the PACS and smartphones. The ICCs of the average parameters of four measurements of HVA and IMA between PACS and smartphones were 0.995 (0.991–0.997) and 0.970 (0.958–0.979), indicating that the two methods were highly correlated. For the smartphone measurement, the interobserver and intraobserver reliability was very good for HVA and IMA. The average measurement time of PACS was 25.41 ± 0.86 s, and the average measurement time of smartphones was 20.29 ± 1.22 s. The smartphone time was significantly faster than that of PACS by approximately 5 s (P<0.001).ConclusionThis novel method using the built-in photo-edit function of smartphones is accurate, reliable, convenient and time-saving in measuring the angles of hallux valgus.

Highlights

Measuring the angles on radiographs is a valuable tool to diagnose and evaluate hallux valgus
The average parameters measured by Picture archiving and communication systems (PACS) were as follows: hallux valgus angle (HVA) average: 37.43 ± 9.61°; intermetatarsal angles (IMAs) average: 13.37 ± 4.01°
The average parameters measured by smartphones were as follows: HVA average: 37.09 ± 9.52° and IMA average: 13.49 ± 3.91°

Summary

Introduction

Measuring the angles on radiographs is a valuable tool to diagnose and evaluate hallux valgus. Some of the valuable angles in assessing hallux valgus include the hallux valgus angle (HVA), the first and second intermetatarsal angle (IMA), the distal metatarsal articular angle (DMAA), the distal articular set angle (DASA), the hallux interphalangeus angle (IPA), the distal medial cuneiform angle (DMCA) and the metatarsus adductus angle (MAA) [2]. These angles are measured by using a marker pen and a protractor on radiograph film. Even though such apps are reliable and time-saving, there are still some shortcomings, such as lack of maintenance and updates, lack of fit for the newest smartphones, bugs or extra payments, and lack of fit for the Android system

Methods

Results

Conclusion