Comparison of plantar pressure distribution patterns of patients with ankylosing spondylitis and asymptomatic healthy individuals: a cross-sectional study

Background: Ankylosing Spondylitis (AS) is an inflammatory chronic disease that causes postural changes. As a result of these changes decreased hip flexion, increased knee flexion and plantar flexion of ankle are developed. Aims: The aim of the study is to compare plantar pressure distribution results in patients with AS and healthy individuals and to determine the relationship between clinical and functional parameters in patients with AS. Methods: Twenty-five patients (median age = 42.2 ± 2.1 years) with AS and 25 healthy individuals (median age = 44.4 ± 1.7 years) were included in the study. The maximum foot pressure (FPmax), average pressure, center of pressure angle (CoP), forefoot load (FFL), rearfoot load (RFL), foot progression angle (FPA) and foot angle (FA) were determined by pedobarographic analysis. Spinal mobility was assessed with lumbar flexion, lateral flexion, and tragus-wall distance. Functional status and disease-related symptoms were assessed with BASDAI, BASFI and ASQoL. Results: There were no differences between static and dynamic pedobarographic analysis parameters between the AS group and the control group (p > 0.05). Self-rated functional levels parameters, pain, and stiffness were higher in the AS group (p < 0.05). Lumbar flexion (p = 0.187) and tragus-to-wall distance (p = 0.196) were similar in two groups. Self-rated parameters were correlated with pain, stiffness, and lateral flexion (p < 0.05). Lateral flexion correlated with FA and FFL; tragus to wall distance correlated with FPmax and CoP and RFL; lumbar flexion correlated with FA (p < 0.05). Conclusion: The results showed that there was no difference plantar pressure distribution but there was a difference in spinal mobility in AS group compared healthy individuals.