Preliminary investigation on the reduction of plantar loading pressure with different insole materials (SRP – Slow Recovery Poron®, P – Poron®, PPF – Poron® + Plastazote, firm and PPS – Poron® + Plastazote, soft)

BackgroundThe aim of this study is to investigate the amount of pressure reduction for different padding and insole materials commonly used in the podiatry clinic.MethodsPlantar pressure were taken for 5 subjects without insoles fitted (BF) in their daily sports shoes, and thereafter with 4 pairs of simple insoles (6.4 mm thick) each as follow: SRP – Slow Recovery Poron®, P – Poron®, PPF – Poron® + Plastazote (firm) and PPS – Poron® + Plastazote (soft). In addition, subjects were also tested with semi-compressed felt (SCF) padding with a 1st metatarsophalangeal joint (MTPJ) aperture cut-out bilaterally. Minimum, maximum, mean pressure and peak pressure at the hallux, 1st, 2nd, 3rd/4th and 5th MTPJ across both feet were analysed. Repeated measures ANOVA with post hoc Bonferroni paired wise comparison was used to test for any statistical significance at the 95% confidence level for all pressure data.ResultsPPF was significant in reducing the minimum (p < 0.005) and mean pressure (p < 0.03) when compared to BF. This accounted for approximately 28% and 27% pressure reduction in minimum and mean pressure respectively. Peak pressure on the 1st MTPJ locality showed significant reduction of 37% and 29% with the use of SCF (p < 0.004) and PPF (p < 0.004), respectively.ConclusionsAll 4 commonly used insole materials were able to reduce pressure across the whole foot with PPF achieving significance. Off-loading the 1st MTPJ would still be best achieved with the commonly used plantar metatarsal pad of SCF with the aperture cut-out design.