For the study, a total contact cast was applied to 17 patients with diabetes and a plantar forefoot ulcer. total contact cast wall load (contact area, peak pressure, and maximum force) at the anterodistal and posterolateral-distal regions of the lower leg were evaluated with two capacitance sensor strips measuring 90cm. Plantar load (contact area, peak pressure, and maximum force) was measured with a capacitance sensor insole placed inside the total contact cast. Both sensors collected data simultaneously at a sampling rate of 50 Hz synchronized to heel strike. The magnitude of total contact cast wall load as a proportion of plantar load was calculated. The total contact cast walls were then removed to determine the differences in plantar loading between the total contact cast and the cut down shoe-cast for the whole foot, rearfoot, midfoot, and forefoot (region of interest). According to the study, the total contact cast wall load was "substantial." Plantar contact areas recorded at the anterodistal lower leg was 48 percent and 34 percent at the posterolateral-distal lower leg. Plantar peak pressure recorded at the anterodistal lower leg was 28 percent and 12 percent at the posterolateral-distal lower leg. Plantar maximum force recorded at the anterodistal lower leg was 12 percent and 4 percent at the posterolateral-distal lower leg. There were significant differences in plantar load between the total contact cast and the cut down shoe-cast for the whole foot, rearfoot, midfoot, and forefoot (region of ulcer). Contact area increased by 5 percent beneath the whole foot, 8 percent at the midfoot, and 6 percent at the forefoot in the shoe-cast. Peak pressure increased by 8 percent beneath the midfoot and 13 percent at the forefoot in the shoe-cast. Maximum force increased 6 percent beneath the midfoot in the shoe-cast. The study authors called each of these increases significant. The study states that offloading plantar neuropathic ulcers using a total contact cast is regarded as the gold standard in patients with diabetes. This study shows that the walls of the total contact cast bear considerable load when measured directly in patients with diabetes and forefoot ulceration. Reduced plantar contact area in the total contact cast compared to the shoe-cast suggests that the foot is suspended by the considerable load bearing capacity of the walls of the total contact cast, which contributes mechanically to the pressure reduction and redistribution properties of the total contact cast. from oandp.com |
