Year

2010

Degree Name

Doctor of Philosophy

Department

University of Wollongong. School of Health Sciences

Abstract

One in three people aged 65 years and above fall at least once every year and this rate increases with age. With the proportion of older people increasing, falls are a devastating health, social and economic problem in Australia and worldwide. Effective evidence-based falls prevention interventions are therefore urgently required to reducethe risk of falling in older people and, in turn, reduce the burden of falls on society. However, modifiable risk factors must first be identified in order to better target these interventions.

During normal gait, the foot is the only source of direct contact with the ground. Therefore, factors that disrupt normal foot structure and function are likely to impair stability and balance and, in turn, increase the risk of falls. Therefore, the primary purpose of this thesis was to determine whether foot pathologies, specifically toe deformities and foot pain, increase the risk of falls in independently-living older people. If the hypotheses held true, the secondary aim was then to explore these foot pathologies to better understand the mechanisms that may contribute to an increased risk of falls in this population.

Three hundred and twelve community-dwelling older men and women aged between 60 and 90 years were randomly recruited to participate in the study. Participants initially underwent a comprehensive baseline assessment that included foot anthropometrics and plantar soft tissue thickness to characterise foot structure. Dynamic plantar pressure, ankle dorsiflexion strength, ankle dorsiflexion flexibility, foot reaction time, hallux and lesser toe flexor strength, postural sway and spatiotemporal gait parameters were measured to characterise foot function. Each participant also had their feet assessed for the presence of foot problems, including lesser toe deformities, hallux valgus and peripheral neuropathy. Disabling foot pain and health-related quality of life were assessed with validated questionnaires. Participants were then followed prospectively, via monthly diaries, to determine their falls incidenceover 12 months.

The presence of hallux valgus, lesser toe deformities and foot pain are common foot pathologies that significantly increase the risk of falling in community-dwelling older people. Older people with toe deformities display altered foot structure, whereby the foot anthropometrics significantly differ and soft tissue thickness under the metatarsal heads is significantly reduced compared to those without toe deformities. Although static balance and spatiotemporal gait characteristics do not seem to be affected by these deformities (p > 0.05), load distribution under the forefoot is altered during ambulation. Foot function is further impaired in older people with toe deformities whereby toe flexor strength is significantly reduced and is a possible contributor to their increased risk of falling (p < 0.01). Similarly, individuals with disabling foot pain reported statistically significantly reduced functional ability, reduced health-related quality of life and displayed altered foot function, in particular foot and ankle muscle weakness, also a possible mechanism associated with an increased risk of falling. Therefore, providing older people with interventions that treat foot problems, foot pain and improve foot function may play a role in reducing falls risk and improving quality of life.

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