Combined three-dimensional gait and plantar pressure analyses detecting significant functional deficits in children with juvenile idiopathic arthritis

Abstract

Background

Children suffering from juvenile idiopathic arthritis (JIA), a heterogeneous group of chronic inflammatory joint diseases, adapt to individual gait patterns to avoid loading of inflamed, swollen and painful joints. As the interpretability of previous studies is limited, this study aims to assess the functional capacity, loads and plantar pressure distribution in the gait of a homogeneous JIA group.

Research question

Does a symmetrical lower limb joint involvement influence the gait dynamics in JIA patients, and how are the results of three-dimensional gait analysis (3DGA) and pedobarography related?

Methods

Fifty JIA patients with symmetrical hip, knee and ankle joint arthritis and 27 healthy controls performed 3DGA and pedobarography at self-selected walking speeds. Kinematics and kinetics of lower limb joints were retrospectively compared in range of motion and in time-normalized waveforms. Plantar load was evaluated by measuring peak pressure, pressure-time integral and maximum force of the whole foot and ten selected foot regions. 1D-SPM analysis, parametric and non-parametric statistical significance tests and correlation coefficients were used for statistical analysis.

Results

JIA patients had a significantly slower walking speed with an anteriorly tilted pelvis and a reduced extension motion of all joints of the lower limb. The horizontal ground reaction forces and generated hip and ankle power during propulsion phase were small. Patients experienced reduced loading at toe regions, which correlated with limited ankle plantarflexion motion in the push-off phase. The total peak pressure was significantly increased and loads at lateral midfoot and metatarsal regions were higher in patients.

Significance

Symmetrical lower limb arthritis is linked to crouch-like gait and restricted gait dynamics with increased total peak pressure. The results confirm earlier results of 3DGA and provide new insights regarding waveform analysis and plantar loading in JIA patients. The used methods help to design individualized functional treatment of JIA patients.

Introduction

Juvenile idiopathic arthritis (JIA) is the mostcommon chronic pediatric rheumatic disease with a broad variety of joint patterns and clinical courses [1], and frequently affects lower limb joints [[1], [2], [3]]. The etiology is not completely understood so far [1]. The clinical symptoms of JIA include joint swelling, effusion and pain causing reflex-pain relieving positioning of affected joints with possible long-term consequences of deformities, hence leading to pain and malfunction of the joints even in absence of active arthritis [1,4]. The disease causes a decreased quality of life and physical inactivity [5,6]. The primary goal is to interrupt and stop the inflammation, and to resume normal joint function to preserve a normal childhood development and participation in everyday life [1,4]. This requires multidisciplinary care as early as possible [1,4]. While medical treatment and disease management improved over the last decades [1], JIA patients are still developing long-lasting functional limitations [2,7,8]. This is a significant risk factor favoring long-term disabilities that continue into adulthood [1,3].

Objective methods such as three-dimensional gait analysis (3DGA) or dynamic pedobarography provide detailed information about the functional capacity of complex dynamic movements [2,9,10]. They are accurate methods determining the joint interaction, joint loading and the interaction of the foot on the ground during daily activities [11]. Both methods share the advantage of detecting disorders early, which could individualize therapy, and prevent permanent changes in bone structure and abnormal stress [12]. This objective evaluation can be an important addition to questionnaires on physical disability of JIA patients, such as the Childhood Health Assessment Questionnaire (CHAQ) [13], which are subjective self-reported perceptions of functional deficits.

Several studies prove, either with 3DGA or pedobarography, that gait impairments are common in JIA patients [2,7,8,[14], [15], [16], [17], [18]]. Characteristically, JIA patients walk with reduced speed, are restricted in lower limb joint kinematics [2,7,8,16] with hyperflexion in the hip and knee joints and limited ankle plantarflexion motion, which was described by Hartmann et al. [7] as a ‘crouch-like’ gait. However, investigations of JIA foot loading profiles were not clear, nor consistent: Dhanendran et al. [14] reported reduced forefoot loading in JIA patients, Orlin et al. [19] found increased JIA foot loading and Hendry et al. [18] described no significant changes in pressure distribution compared to healthy controls. The reasons for these unequivocal results could be due to heterogeneously affected joint patterns, changes in medical interventions during the last decades, or a limited number of examined patients.

The aim of this study was to assess the functional capacity of JIA patients with bilateral lower limb joint involvement during walking in comparison with healthy children using both pedobarography and 3DGA. This is the first study presenting and combining kinematic, kinetic and foot pressure data of a homogenous JIA sample.