Validation of non-radiographic APECS software in comparison with standard radiographic measurement of full-length lower limb hip-knee-ankle angle in elderly obese women

Abstract

IntroductionEvidence suggests that obesity and ageing in women are linked to angular knee abnormalities. The hip-knee-ankle (HKA) angle on a full-limb radiograph is the gold standard measure of lower limb alignment. The AI Posture Evaluation and Correction System (APECS) software is a non-radiographic mobile application designed for whole-body posture assessment. Since exposure to X-ray is associated with harmful effects, there is a need to find a safe and valid alternative for measuring HKA angle. The objective of this research was to determine the validity of the non-radiographic APECS software in comparison with standard radiographic measurement of HKA angle.MethodsThe present cross-sectional diagnostic accuracy study was conducted in a tertiary care hospital of Belagavi, Karnataka, India. Overall, 45 elderly obese females aged 60–80 years with a body mass index of 25 were included. HKA angle was marked bilaterally. Full-limb radiographs were taken and angles were marked with 2.0 version software, DXM model. For the APECS software, full-limb photographs were taken with landmarks indicated with radiant markers and angles were autogenerated by the software.ResultsThe Pearson correlation coefficient between the APECS application and the gold standard (X-ray) was 0.9874 (98.74% of matching). The agreement between standard radiograph and the average of all examiners’ APECS Pro measurements (including right and left sides) equalled 94.64% (kappa = 0.8323; <i>p</i> = 0.001), which suggests very good agreement.ConclusionsThe APECS application demonstrated a high percentage of matching (98.74%) and agreement (94.64%), indicating its excellent validity in measuring HKA angle.