Effect of different casting design characteristics on offloading the diabetic foot

Area of Science:

• Biomechanics
• Diabetic Foot Care
• Orthotics

Background:

• Non-removable knee-high devices, like total contact casts (TCCs), are standard for offloading diabetic plantar forefoot ulcers.
• The specific contributions of TCC design features to offloading effectiveness are not fully understood.

Purpose of the Study:

• To investigate the offloading effects of various design characteristics of non-removable knee-high casts in individuals with diabetes and plantar forefoot ulcers.

Main Methods:

• Plantar pressures and walking comfort were assessed in 16 participants with diabetes using different non-removable knee-high cast configurations.
• Tested devices included a TCC, a removable TCC (BTCC), a cast shoe, and variations of the cast shoe.

Main Results:

• The TCC demonstrated significantly lower peak pressures (up to 47%) compared to the BTCC at the hallux, midfoot, and ulcer sites.
• The BTCC showed substantial reductions in peak pressures (up to 47%) compared to the cast shoe in forefoot and ulcer regions.
• Both TCC and BTCC reduced the force-time integral compared to the cast shoe, with TCC and BTCC impacting walking comfort differently.

Conclusions:

• The knee-high, non-removable nature of the TCC provides superior offloading via an optimal 'shaft effect'.
• While effective for offloading, the TCC can negatively impact walking comfort.
• Findings support informed clinical decisions regarding offloading strategies for diabetic plantar forefoot ulcers.