Analysis of the reliability of KEOPS version 2 for the measurement of coronal and sagittal parameters in spinal deformity

The purpose of the study is to evaluate the updated version of this software in patients with various spinal deformity.

Sixty patients were included in this study and were divided into three categories: 20 patients with AIS, 20 patients with ASD, and 20 patients having undergone corrective surgery for spinal deformity. The measurements were performed by two senior and two junior orthopedic surgery residents, and were done at two points in time separated by a 3-week interval with the cases being randomized every time to reduce the risk of memory bias. Measured parameters included coronal, sagittal, global alignment parameters, and pelvic parameters.

When assessing the inter- and intra-observer reliability across all the groups of patients, none of the coefficients was smaller than 0.8 with a very high level of agreement. The standard error ranged from 0.7° to 1.5° demonstrating a high level of accuracy. Fairly similar results were seen when the groups were divided into the three categories except for the post-operative groups where a strong and not perfect level of agreement was reported.

This is the first study to assess the reproducibility of the new version of KEOPS, showing a very high agreement in all measurements. In the post-operative group, although it showed a strong agreement, the lower performance can be explained by the presence of surgical material making it harder to identify the anatomical landmarks accurately. Nevertheless, we can recommend the usage of this software in a clinical setting.