Impact of Removable Cast Walker Design on Usability for Patients With Diabetic Foot Ulcers

Improving Diabetic Foot Ulcer Offloading: A Pilot Study on the Impact of Removable Cast Walker Design Factors on Usability

Within their lifetime, over 30% of people living with diabetes will develop a diabetic foot ulcer (DFU), many of which will never heal and may require amputation. Removable cast walkers (RCWs) are commonly prescribed to offload (treat) DFUs. While RCWs are prescribed to be worn during all weight bearing activities, adherence to this prescription is low. This is a serious concern given that low adherence predicts poor DFU healing. This study will provide pilot/feasibility data to inform a larger clinical trial to evaluate the impact of existing RCW designs on adherence and DFU healing. We will also quantify the effect of RCW form on biomechanical and self-reported measures related to usability. Our working hypothesis is that healing outcomes with a given RCW will be predicted by biomechanical and self-reported measures of RCW usability, with the predictive relationship partly explained by the effect of these measures on adherence.

Inclusion Criteria:

• presence of a full thickness plantar (forefoot) diabetic foot ulcer ≥1cm2 that is being treated on an outpatient basis with a University of Texas wound classification of 1A-C or 2 A-C;
• self-reported ability to walk for at least two continuous minutes at a self-selected speed
• confirmation of the presence of diabetic peripheral neuropathy as identified by failure to detect a 10 gram Semmes Weinstein Monofilament on either foot at one of four sites tested (1st, 3rd, 5th metatarsal heads, and plantar surface of hallux) OR a vibration perception threshold value of 25 or more at either hallux.

Exclusion Criteria:

• lower extremity amputation more proximal than transmetatarsal on either limb
• chronic kidney disease stage 4 or higher (i.e., currently undergoing dialysis or eGFR<30 within last 60 days)
• active Charcot neuroarthropathy
• severe peripheral arterial disease (non-palpable pulse at posterior tibia and dorsalis pedis arteries, and an ankle brachial index<0.7)
• gait/balance disturbance not attributable to diabetes (e.g. neuromuscular disease or cerebrovascular vascular accident)
• current or previous (within past year) use of an ankle-high RCW or of a contralateral lift to offset an RCW-induced LLD