Despite recommendations in (inter)national guidelines to use knee-high non-removable casts to offload diabetic foot ulcers, felt-padding is still widely used in daily clinical practice. The offloading effectiveness of this felt has hardly been studied, creating a clinically relevant gap in the literature. Researchers from LaTrobe University and Northern Health, both in Melbourne, have now filled this gap.
Anita Raspovic and her colleagues investigated plantar pressures in 15 patients with 16 plantar diabetic foot ulcers. They measured plantar pressure while patients walked in standard post-op shoes with and without felt-padding, and seven days later. Felt reduced plantar pressures by about 50% (from 370 to 190kPa), but part of this effect was lost during the first seven days (32% increase to 250kPa).
While these reductions show an effectiveness of felt-padding, the authors rightly discuss the superiority of knee-high devices. These devices result in plantar pressure reductions of around 90%, with mean plantar pressures around 100kPa. Felt-padding may, however, be a useful addition to these devices. This has not been studied, but it is likely that a knee-high device plus felt-padding reduces plantar pressure even further.
Two messages can be taken home from this research: first, felt-padding does provide plantar pressure reduction, but (inter)nationally recommended gold-standard offloading devices are much better in offloading a diabetic foot ulcer. Second, if felt-padding is the only available offloading method possible in a patient, it needs to be changed on a weekly basis to keep its offloading capacity.