The Effect of Lateral Wedging on Foot Function in Walking and Running Gait

A lateral wedge is an underfoot intervention often added to foot orthoses by sloping material so that the lateral side is higher or thicker compared to the medial side. Podiatrists prescribe foot orthoses, which often incorporate lateral wedges, to alter foot function and reduce symptoms in the lower limb. Despite the anecdotally reported frequent use of lateral wedges in podiatric practice, there is limited evidence concerning their clinical application or biomechanical outcomes in healthy populations. To address this gap, this thesis had two aims: first, to understand how lateral wedges are applied clinically, including their frequency of use, the diagnoses they are used to address, and how they are fabricated and positioned; and second, to evaluate how lateral wedges affect foot function, specifically first metatarsophalangeal joint motion and centre of pressure during walking and running gait. To meet these aims, a series of four studies was developed, which have been presented in this thesis. Firstly, to develop an understanding of the prescription habits of New Zealand (NZ) podiatrists 1000 custom foot orthosis prescriptions were obtained and analysed to determine the frequency and symmetry of orthotic prescription characteristics. A lateral wedge was included in 22% of prescriptions and was more likely to be utilised for the management of plantar heel pain or ankle sprains. Secondly, a scoping review was conducted to map existing research on the effect of lateral wedges in healthy adults. This review identified insufficient descriptions of wedge design, with many studies omitting details of the materials used to manufacture lateral wedges and their placement. Most included studies (95%) examined full-length, rearfoot, or sulcus-length wedges, with an average wedge inclination of 6°. No evidence was found contrasting the effects of lateral wedges for running versus walking gait. Thirdly, an online survey found that 86% of NZ podiatrists believed lateral wedging increased first metatarsophalangeal joint ...