# Association Between Calcaneal Inclination Angle and Spinal and Lower Limb Alignment: A Retrospective Radiographic Analysis

## TL;DR

This study found that foot shape variations are linked to spinal and lower limb alignment, suggesting foot morphology could influence posture-related disorders.

## Contribution

The study provides new evidence of moderate correlations between foot parameters and spinal/lower limb alignment in a clinical context.

## Key findings

- Significant differences in pelvic tilt were found among foot morphology subgroups.
- Moderate associations were observed between calcaneal inclination angle and pelvic parameters like PI, PT, SS, and LL.
- Foot morphology showed moderate correlations with knee and pelvic alignment.

## Abstract

Background/Objectives: This study aimed to clinically investigate how variations in foot morphology influence spinal and lower limb alignment, based on the concept of an ascending kinetic chain. Methods: We analyzed the medical records of 100 patients who met the inclusion criteria. The X-ray image data used in the analysis included weight-bearing lateral views of both feet, whole-spine anteroposterior (AP) and lateral views, and full-length standing AP scanograms of the lower legs. In the obtained X-ray images, Calcaneal Inclination Angle (CIA), Tibiotalar Tilt Angle (TTA), Tibiotalar Angle (TA), Quadriceps Angle (Q-angle), Pelvic Incidence (PI), Pelvic Tilt (PT), Sacral Slope (SS), and L1–S1 Lordosis (LL) were measured. Participants were categorized into subgroups based on their CIA values: Pes Planus, Normal, and Pes Cavus. These subgroups were analyzed by foot orientation (right and left) using one-way analysis of variance (ANOVA) and Pearson correlation coefficient analysis. Results: The one-way ANOVA identified significant differences in mean right foot PT values among subgroups. Correlation analysis shows moderate associations between foot CIA and Q-angle of the knee, as well as pelvic parameters including PI, PT, SS, and LL. Conclusions: Analysis of the correlation between foot parameters and body alignment, in the context of diagnostic and evaluative aspects of Chuna manual medicine (CMM), revealed moderate correlations among the foot, ankle, knee, pelvis, and lumbosacral regions. These findings suggest that foot morphology may play a clinically relevant role in posture-related disorders and could contribute to preventive and corrective strategies for musculoskeletal alignment.