Assessment of the rocker sole shoes on postural stability in patients with type 2 diabetes and distal sensorimotor polyneuropathy

Abstract

Distal sensorimotor polyneuropathy (DPN) is a leading risk factor of developing ulcer, including increased pressures at the forefoot. The rocker sole shoes are prescribed to decrease pressures but could induce instability [1] . The aim of this study was to compare the postural stability between normal shoes (NS) and rocker sole shoes (RSS) in patients with type 2 diabetes and DPN. In this preliminary, randomized, controlled study, NS and RSS were compared during static standing and gait. The primary outcome was the biomechanical variable COP-COM (corresponding to the mean distance between the center of pressure and the center of mass) [2] . The center of mass (COM) was calculated with the anthropometric table [3] using the motion analysis system Vicon, when the ground reaction forces and moments were recorded by 2 AMTI force platforms allowing to compute the center of pressure (COP). The root mean square (RMS) amplitudes were calculated in both anterior/posterior (AP) and medial/lateral (ML) directions, eyes open (EO) and closed (EC). The secondary outcomes were the clinical variables “Berg Balance Scale” (BBS) and “Dynamic Gait Index” (DGI) and a score determinated from 9 spatiotemporal parameters: the “Gait Variability Index” (GVI). Eighteen patients with type 2 diabetes were included with a mean age 63.3 ± 8.6 years, and BMI 30.3 ± 5.1. There was no statistically difference between NS and RSS for the COP-COM variable in all conditions (AP: P = 0.96 EO and P = 0.68 EC; ML: P = 0.75 EO and P = 0.13 EC), and also for the other variables BBS, DGI and GVI ( P > 0.05). However, the stance time was significantly reduced ( P = 0.01) and the swing time was significantly increased ( P = 0.02). The rocker sole shoes seem to induce postural change during gait, without significant differences in quiet standing. For future studies, more sensitive assessment must be used and the number of subjects has to be increased to confirm these results.