Body mass index and maximum available midfoot motion are associated with midfoot angle at peak heel rise in people with type 2 diabetes mellitus and peripheral neuropathy.

Purpose: Midfoot movement dysfunction, as measured by heel rise performance, is associated with midfoot deformity in people with diabetes and peripheral neuropathy. Understanding contributors of midfoot movement dysfunction may help clinicians understand deformity progression. The purpose of this study was to determine the factors associated with midfoot angle at peak heel rise.

Methods: The outcomes of fifty-eight participants with type 2 diabetes mellitus and peripheral neuropathy were analyzed. Midfoot (forefoot on hindfoot) sagittal kinematics during unilateral heel rise task were measured using 3-dimensional motion analysis. A multivariate linear regression model was used to predict midfoot sagittal movements at peak heel rise. Independent variables that were entered in the model were (in order of entry): age, body mass index, intrinsic foot muscle volume, and maximum available midfoot plantarflexion range of motion. Intrinsic foot muscle volume was obtained from magnetic resonance imaging and maximum available midfoot motion was measured during non-weightbearing plantarflexion using 3-dimensional motion analysis.

Results: Body mass index (R = 30.5%, p < 0.001) and maximum available midfoot plantarflexion range of motion (R = 10.9%, p = 0.001) were significant factors that accounted for 41.4% of variance of midfoot angle at peak heel rise, while age and intrinsic foot muscle volume were not significant predictors.

Conclusions: Greater body mass index and less available midfoot plantarflexion range of motion were associated with greater midfoot movement dysfunction. These two significant predictors are potentially modifiable, suggesting possible improvements in midfoot movements with reduction in body weight and increasing midfoot plantarflexion range of motion. Health care professionals should consider patient's weight and joint motion when prescribing foot exercise(s) to prevent excessive midfoot collapse during weightbearing tasks.