# Optomechanical Analysis of Gait in Patients with Ankylosing Spondylitis

## TL;DR

This study uses advanced tools to analyze how people with ankylosing spondylitis walk, finding changes in pressure and stride length but not in joint movement.

## Contribution

This is the first study to combine pedobarography and markerless motion capture for gait analysis in ankylosing spondylitis patients.

## Key findings

- AS patients showed altered pressure distribution in specific foot quadrants compared to healthy controls.
- AS patients had a significantly shorter stride length and higher midfoot peak force during dynamic gait.
- No significant differences were found in hip, knee, or ankle joint angles between the groups.

## Abstract

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease associated with alterations in posture and gait. The aim of this study was to assess the gait of AS patients using pedobarography and a markerless motion capture system. This is the first study of this population to combine these two methods. Twelve AS patients and twelve healthy controls were enrolled in this study. An instrumented gait analysis of both groups was performed using pedobarography and Microsoft Kinect v2. The AS group was significantly older than the controls (p < 0.05). The AS group showed a significantly lower relative pressure distribution in the front-right quadrant (p = 0.01) and a significantly higher relative pressure distribution in the rear-right quadrant (p = 0.05) on the static pedobarography. The AS group also had a higher peak force in the midfoot on the dynamic pedobarography (p < 0.05). The AS group had a significantly shorter stride length (p = 0.01). No significant differences between the groups were found in their hip flexion/extension and adduction/abduction, knee flexion, or ankle dorsiflexion/plantarflexion angles. This study shows significant alterations in the pedobarographic and spatiotemporal, but not in the kinematic, gait parameters of AS patients. These alterations represent a feature of AS and not antalgic adjustments. Rehabilitation programs for AS patients could be tailored according to the results of an instrumented gait analysis and should include balance and gait exercises.