Validity and reliability of hallux valgus angle measured on digital photographs

Nix, Sheree, Russell, Trevor, Vicenzino, Bill and Smith, Michelle (2012) Validity and reliability of hallux valgus angle measured on digital photographs. Journal of Orthopaedic and Sports Physical Therapy, 42 7: 642-648. doi:10.2519/jospt.2012.3841

Author Nix, Sheree
Russell, Trevor
Vicenzino, Bill
Smith, Michelle
Title Validity and reliability of hallux valgus angle measured on digital photographs
Journal name Journal of Orthopaedic and Sports Physical Therapy   Check publisher's open access policy
ISSN 0190-6011
Publication date 2012-07
Sub-type Article (original research)
DOI 10.2519/jospt.2012.3841
Volume 42
Issue 7
Start page 642
End page 648
Total pages 7
Place of publication Alexandria, VA, United States
Publisher American Physical Therapy Association
Collection year 2013
Language eng
Formatted abstract
Study Design: Controlled laboratory study.

Objectives: To investigate the reliability and concurrent validity of photographic measurements of hallux valgus angle compared to radiographs as the criterion standard.

Background: Clinical assessment of hallux valgus involves measuring alignment between the first toe and metatarsal on weight-bearing radiographs or visually grading the severity of deformity with categorical scales. Digital photographs offer a noninvasive method of measuring deformity on an exact scale; however, the validity of this technique has not previously been established.

Methods: Thirty-eight subjects (30 female, 8 male) were examined (76 feet, 54 with hallux valgus). Computer software was used to measure hallux valgus angle from digital records of bilateral weight-bearing dorsoplantar foot radiographs and photographs. One examiner measured 76 feet on 2 occasions 2 weeks apart, and a second examiner measured 40 feet on a single occasion. Reliability was investigated by intraclass correlation coefficients and validity by 95% limits of agreement. The Pearson correlation coefficient was also calculated.

Results: Intrarater and interrater reliability were very high (intraclass correlation coefficients greater than 0.96) and 95% limits of agreement between photographic and radiographic measurements were acceptable. Measurements from photographs and radiographs were also highly correlated (Pearson r = 0.96).

Conclusion: Digital photographic measurements of hallux valgus angle are reliable and have acceptable validity compared to weight-bearing radiographs. This method provides a convenient and precise tool in assessment of hallux valgus, while avoiding the cost and radiation exposure associated with radiographs.
Keyword Foot deformity
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online: 25 January 2012.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Health and Rehabilitation Sciences Publications
School of Medicine Publications
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Citation counts: TR Web of Science Citation Count  Cited 7 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 6 times in Scopus Article | Citations
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Created: Thu, 29 Mar 2012, 06:22:27 EST by Dr Michelle Smith on behalf of School of Health & Rehabilitation Sciences