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. 2012 Aug;36(8):1655-60.
doi: 10.1007/s00264-012-1579-5. Epub 2012 Jun 1.

Measuring the Cobb angle with the iPhone in kyphoses: a reliability study

Frederic Jacquot  1 , Axelle Charpentier, Sofiane Khelifi, Daniel Gastambide, Regis Rigal, Alain Sautet
Affiliations

Measuring the Cobb angle with the iPhone in kyphoses: a reliability study

Frederic Jacquot et al. Int Orthop. 2012 Aug.

Abstract

Purpose: Smartphones have gained widespread use in the healthcare field to fulfill a variety of tasks. We developed a small iPhone application to take advantage of the built-in position sensor to measure angles in a variety of spinal deformities. We present a reliability study of this tool in measuring kyphotic angles.

Methods: Radiographs taken from 20 different patients' charts were presented to a panel of six operators at two different times. Radiographs were measured with the protractor and the iPhone application and statistical analysis was applied to measure intraclass correlation coefficients between both measurement methods, and to measure intra- and interobserver reliability

Results: The intraclass correlation coefficient calculated between methods (i.e. CobbMeter application on the iPhone versus standard method with the protractor) was 0.963 for all measures, indicating excellent correlation was obtained between the CobbMeter application and the standard method. The interobserver correlation coefficient was 0.965. The intraobserver ICC was 0.977, indicating excellent reproductibility of measurements at different times for all operators. The interobserver ICC between fellowship trained senior surgeons and general orthopaedic residents was 0.989. Consistently, the ICC for intraobserver and interobserver correlations was higher with the CobbMeter application than with the regular protractor method. This difference was not statistically significant.

Conclusion: Measuring kyphotic angles with the iPhone application appears to be a valid procedure and is in no way inferior to the standard way of measuring the Cobb angle in kyphotic deformities.

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Figures

Fig. 1
Fig. 1
Measuring process using the handheld device: aligning the edge of the device with the edge of the upper vertebra to the deformity
Fig. 2
Fig. 2
Measuring process using the handheld device. Second step: aligning the handheld device with the edge of the lower vertebra and validating
Fig. 3
Fig. 3
Measuring process: the resulting angle is then printed onto the screen of the device
Fig. 4
Fig. 4
Comparison between methods
Fig. 5
Fig. 5
Intraobserver variability for both tools
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References

    1. Cobb JR. Outline for the study of scoliosis. AAOS Instr Course Lect. 1948;5:261–275.
    1. Cobb JR. Progress in orthopedic surgery for 1945; conditions involving the spine and thorax, exclusive of those in the lower part of the back. Arch Surg. 1947;55(1):76–87. doi: 10.1001/archsurg.1947.01230080079007. - DOI - PubMed
    1. Keynan O, Fisher CG, Vaccaro A, Fehlings MG, Oner FC, Dietz J, Kwon B, Rampersaud R, Bono C, France J, Dvorak M. Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group. Spine (Phila Pa 1976) 2006;31(5):E156–E165. doi: 10.1097/01.brs.0000201261.94907.0d. - DOI - PubMed
    1. Ulmar B, Brunner A, Guhring M, Schmalzle T, Weise K, Badke A. Inter- and intraobserver reliability of the vertebral, local and segmental kyphosis in 120 traumatic lumbar and thoracic burst fractures: evaluation in lateral X-rays and sagittal computed tomographies. Eur Spine J. 2009;19(4):558–566. doi: 10.1007/s00586-009-1231-2. - DOI - PMC - PubMed
    1. Al-Hadithy N, Gikas PD, Al-Nammari SS (2012) Smartphones in orthopaedics. Int Orthop. doi:10.1007/s00264-012-1527-4 - PMC - PubMed

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