Elsevier

The Journal of Foot and Ankle Surgery

Volume 49, Issue 6, November–December 2010, Pages 523-528
The Journal of Foot and Ankle Surgery

Original Research
Radiographic Angles in Hallux Valgus: Comparison between Manual and Computer-Assisted Measurements

https://doi.org/10.1053/j.jfas.2010.07.012Get rights and content

Abstract

Radiographic angles are used to assess the severity of hallux valgus deformity, in preoperative planning, assessing postoperative outcomes, and in comparing results between interventions. The manual method to measure these angles has been shown to be prone to errors and to be time consuming. Computer programs are now available to assist in angular measurements.

This study was undertaken to compare the reliability and time taken between the 2 methods. A total of 30 radiographs were used from a population of patients with hallux valgus deformity. The radiographs were digitized for computer-assisted measurements. The technical error of measurement (TEM) was calculated for intra- and interobserver data to assess the error in angular measurement with both methods.

The technical error of measurement was lower with the computer-assisted method, suggesting that this method is more reliable. Furthermore, the time taken was also reduced with this method.)

Section snippets

Objectives

The main objective of this study was to compare the inter- and intraobserver reliability between manual measurements using marker pen and goniometer, and computer-assisted measurements of digitized images using software, for radiographic angles in hallux valgus (HVA, IMA, DMAA, and IPA). The secondary objective was to compare the time taken between these 2 methods.

Study design

This observational study was conducted at Stafford General Hospitals NHS Trust, after approval from the local research and ethics committee (LREC).

Selection of radiographs

Thirty radiographs performed preoperatively for patients with hallux valgus deformity seen in an outpatient clinic in January 2007 were used in this study. The radiographs had been taken using standard technique with the patients weight bearing, 15-degree angulation of the x-ray tube toward the ankle, and centered on the midfoot. All identifying

Intraobserver data

The intraobserver error was assessed by calculating the TEM for the 3 observers (Table 2). The intraobserver error was less with the computer-assisted method for all 4 angles, including the DMAA. The TEM (observer 1) improved from 2.32 to 2.24 for HVA, 1.9 to 1.33 for IMA, 3.9 to 2.97 for DMAA, and 2.03 to 1.84 for IPA. Furthermore, the error was reduced for the other 2 observers, including observer 3 who had the least experience and skill level in performing angular measurements for hallux

Discussion

Radiographic angles are measured to assess severity of deformity, choose type of surgical procedure, assess postoperative correction, and compare results. The use of angular measurements is based on the belief that they are reliable, repeatable, and provide a constant value for comparison with other studies. The traditional method of measuring angles on plain radiographs is by using marker pens, placing reference points, identifying axis of the respective bones, and measuring angles with a

Acknowledgment

The authors acknowledge the technical assistance provided by Dr Chi-Wen Lung.

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    Financial Disclosure: None reported.

    Conflict of Interest: None reported.

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