Plantar pressure measurements to investigate the offloading effect of total contact softcast and total contact cast for plantar diabetic foot ulcers

Background: Total contact softcast is an offloading device for plantar diabetic foot ulcers. Compared with conventional knee-high total contact casts, the total contact softcast is shorter, lighter, and partially flexible. However, its pressure offloading effects are unknown. Methods: In patients with plantar diabetic foot ulcers, mean peak plantar pressure was measured at the ulcer and 6 plantar foot regions in total contact softcast, total contact cast, and patient's own footwear. Patient-reported comfort was investigated using a visual analogue scale. Findings: We included 20 patients. Mean peak plantar pressure at the ulcer site was significantly higher in total contact softcast (median, 505 kilopascal; interquartile range, 319;628 kilopascal) than in total contact cast (median, 320 kilopascal; interquartile range, 182;606 kilopascal; p = 0.011). Mean peak plantar pressure in total contact softcast was higher in all plantar regions except for the hindfoot. Peak plantar pressures were lower in total contact softcast than in patient's own footwear at the hallux, toes, and midfoot. Patient-reported comfort visual analogue scale scores during walking were significantly better in total contact softcast (median, 8.8; interquartile range, 6.8;9.4) than in total contact cast (median, 3.8; interquartile range, 1.7;4.9; p < 0.001). Interpretation: Peak plantar pressure was significantly higher in total contact softcast than in total contact cast at the diabetic foot ulcer site and all plantar foot regions, except the hindfoot. Patient-reported comfort was better in total contact softcast. Because reported clinical outcomes of total contact softcast are favorable, further prospective investigation is warranted.