Interrater reliability of a new tool to analyze sagittal parameters in camptocormic patients: The 3D morphological analysis system SAM3D®.

BACKGROUND

Camptocormia is a trunk flexion occurring during walking that the patient can spontaneously correct in a static position. Therefore, capturing the flexed trunk posture on radiograph is difficult.

OBJECTIVE

To analyze the interrater reliability in different positions reflecting the dynamic phenomenon of camptocormia using a non-invasive visual three-dimensional capture tool.

METHODS

Sample size calculation was at least 31 participants. 34 patients who had camptocormia and were monitored in our clinical practice were included. Two different examiners performed measurements using SAM3D tool in the three following positions: Spontaneous Standing Position (SSP), Upright Standing Position (USP), and Walking-like Standing Position (WSP). Sagittal parameters were measured: arrow in C7, kyphosis, lordosis, and knee flexion. The interrater reliability was assessed using Lin's Concordance Correlation Coefficient (CCC).

RESULTS

Regarding the arrow in C7, the Lin's CCCs were excellent, respectively 0.96 (SSP), 0.98 (USP), and 0.97 (WSP). All the CCCs for other parameters were at least fairly good (>0.87). There were significant differences in arrows in C7 between USP and the two other positions (SSP and WSP).

CONCLUSION

SAM3D is a non-invasive visual three-dimensional capture tool allowing safe and automatic assessments, and repeated measurements with good interrater reliability.