Validity and reliability of a smartphone application for knee posture quantification and the effects of external markers on the precision of this measure

George Schayer Sabino; Luís Augusto Ferraz de Souza; Tainá Ribeiro; Diego Henrique Antunes Nascimento; Claysson Bruno Santos Vimieiro; Renan Alves Resende

doi:10.1016/j.jbmt.2021.07.027

Validity and reliability of a smartphone application for knee posture quantification and the effects of external markers on the precision of this measure

J Bodyw Mov Ther. 2021 Oct:28:42-48. doi: 10.1016/j.jbmt.2021.07.027. Epub 2021 Aug 12.

Authors

George Schayer Sabino¹, Luís Augusto Ferraz de Souza², Tainá Ribeiro², Diego Henrique Antunes Nascimento³, Claysson Bruno Santos Vimieiro⁴, Renan Alves Resende⁵

Affiliations

¹ Universidade Federal de Minas Gerais, School of Physical Education, Physical Therapy and Occupational Therapy, Graduate Program in Rehabilitation Sciences, Department of Physical Therapy, Avenida Antônio Carlos 6627 Campus Pampulha, 31270-901, Belo Horizonte, MG, Brazil; Faculdade Ciências Médicas de Minas, Alameda Ezequiel Dias, 275, CEP: 30130-110, Belo Horizonte, MG, Brazil.
² Universidade Federal de Minas Gerais, School of Physical Education, Physical Therapy and Occupational Therapy, Graduate Program in Rehabilitation Sciences, Department of Physical Therapy, Avenida Antônio Carlos 6627 Campus Pampulha, 31270-901, Belo Horizonte, MG, Brazil.
³ Universidade Federal de Minas Gerais, Bioengineering Laboratory, Graduate Program in Mechanical Engineering, Avenida Antônio Carlos 6627 Campus Pampulha, 31270-901, Belo Horizonte, MG, Brazil.
⁴ Universidade Federal de Minas Gerais, Bioengineering Laboratory, Graduate Program in Mechanical Engineering, Avenida Antônio Carlos 6627 Campus Pampulha, 31270-901, Belo Horizonte, MG, Brazil; Pontifícia Universidade Católica de Minas Gerais, Graduate Program in Mechanical Engineering, Avenida Dom José Gaspar 500, Coração Eucarístico, 30535-901, Belo Horizonte, MG, Brazil.
⁵ Universidade Federal de Minas Gerais, School of Physical Education, Physical Therapy and Occupational Therapy, Graduate Program in Rehabilitation Sciences, Department of Physical Therapy, Avenida Antônio Carlos 6627 Campus Pampulha, 31270-901, Belo Horizonte, MG, Brazil. Electronic address: renan.aresende@gmail.com.

PMID: 34776173
DOI: 10.1016/j.jbmt.2021.07.027

Abstract

Background: Technological resources, such as smartphones can contribute to the quantitative assessment of posture.

Purposes: Test the validity and reliability of using a postural assessment application to quantify the frontal plane knee posture in orthostatism and to test the influence of the use of external markers on the precision of this measure.

Design: Methodological study.

Methods: The knee frontal plane posture of 30 volunteers were analyzed by two independent examiners. The photographs were taken with different external marker arrangements. The photographs were analyzed at two moments using the Kinovea software and PhysioCode Posture (PCP) application. Reliability was analyzed using the intraclass correlation coefficient (ICC) between measures with each instrument conducted at two moments with a 7-day interval. Concurrent validity of PCP with Kinovea measure was analyzed using Pearson's correlation coefficient. Standard error measurement (SEM), minimum detectable change (MDC) and Bland Altman plots were analyzed.

Results: PCP demonstrated excellent intra-rater [ICC = 0.92 (95% confidence interval [CI] 0.90-0.93)] and inter-rater [ICC = 0.88 (95%CI 0.85-0.90)] reliability. Concurrent validity analysis showed excellent agreement between PCP and Kinovea software (r = 0.88). The use of markers, independent of positioning, did not influence the measurement properties of measures with both softwares. The SEM was inferior to 1.2°, and the MDC was below 2.85°. No systematic errors were observed in the Bland Altman graphs.

Conclusions: The use of PCP application to measure knee posture was valid and demonstrated excellent intra- and inter-rater reliability levels. The use of external markers did not influence the measurement.

Keywords: Photography; Posture; Smartphone; Technology assessment.

MeSH terms

Humans
Knee Joint
Mobile Applications*
Posture
Reproducibility of Results
Smartphone*