Generalized hypermobility syndrome (GHS) alters dynamic plantar pressure characteristics

Background: In the relevant literature generalized hypermobility syndrome (GHS) has been shown to alter the kinetic and kinematic patterns of the human movement system. Although GHS affects the general body biomechanics of individuals, the body of knowledge in plantar pressure distribution in GHS is far from sufficient.

Objective: The aim of this study was to determine whether individuals with joint hypermobility syndrome have abnormal plantar pressure distribution during normal gait compared to healthy individuals.

Methods: A total of 37 participants (mean age: 22.16 ± 2.58 years) diagnosed with GHS and 37 aged-matched participants (mean age: 23.35 ± 2.85 years) without GHS were included in the study. Dynamic plantar pressure distribution was obtained as each participant walked in barefoot at a self-selected pace over EMED-m system (Novel GmbH, Munich, Germany). Correlations between hypermobility score (HS) (Beighton score) and plantar pressure variables, and between group differences in peak pressure (PP), pressure-time integral (PTI), average pressure (AP) and maximum force (MxF) were computed for 10 regions under the sole.

Results: HS was significantly correlated with peak pressure under the mid-foot (MF) (r= 0.24, p= 0.043), 5th metatarsal head (MH5) (r= 0.33, p= 0.001), big toe (BT) (r= 0.44, p< 0.001), and second toe (ST) (r= 0.38, p= 0.001). A similar trend was observed for pressure-time integrals under hindfoot (HF) (r= 0.24, p= 0.04), MF (r= 0.30, p= 0.009), MH5 (r= 0.25, p= 0.033), BT (r= 0.37, p= 0.001) and ST (r= 0.34, p= 0.003). The only significant MxF detected was under the ST (r= 0.23, p= 0.048), and AP was determined to be significantly higher as HS increases indicated by APs under MH5 (r= 0.24, p= 0.042), BT (r= 0.32, p= 0.005) and ST (r= 0.40, p< 0.001). Peak pressure values under HF were significantly higher in the hypermobile group (p= 0.023), MH5 (p= 0.001), BT (p< 0.001) and ST (p= 0.003). AP and PTI were also found to be significantly higher in the hypermobile group under MH5 (p= 0.009), BT (p= 0.037), and ST (p= 0.003). MxF was higher only under MF5 (p= 0.029) and SF (p= 0.041) in the hypermobile group.

Conclusion: The forefoot regions received a higher load in GHS during gait. This could be useful in clinical evaluation of the foot in GHS, preventing potential injuries of lower extremity, and also in processes related to decision making for foot orthotics and/or rehabilitation protocols.