The relationship between Foot Posture Index and plantar pressure in a community-dwelling adult population with Type 2 diabetes

Aims: To investigate the contribution of foot type to plantar pressures in a community-dwelling adult population with type 2 diabetes. Methods: Foot Posture Index-6 (FPI-6) as a measure of foot type, barefoot plantar pressure (peak pressures and pressure-time integrals), presence of forefoot deformities, peripheral neuropathy, ankle and first metatarsophalangeal joint (MTPJ) dorsiflexion range of motion (ROM), and demographic variables were measured. Standard multiple regression models were used to investigate the independent contribution of FPI-6 on plantar pressure variables at the hallux, forefoot, and rearfoot. Results: 122 adults (mean age 70.9 ± 9.3, n = 58 female) with type 2 diabetes were recruited. A lower (more supinated) FPI-6 significantly contributed to an increased forefoot pressure-time integral (β = −0.285, p = 0.04). FPI-6 was not a statistically significant independent predictor of peak pressure at the hallux, forefoot or rearfoot. Conclusions: When screening for at-risk sites of elevated plantar pressure in adults with type 2 diabetes, clinicians should consider performing the FPI-6 along with other clinical measures that have been shown to be associated with increased plantar pressures including first MTPJ dorsiflexion ROM, and presence of digital deformities. Evidence-based treatments to offload these areas should then be considered.