Improving Diabetic Foot Ulcer Offloading: A Pilot Study on the Impact of Removable Cast Walker Design Factors on Usability - ABSTRACT
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. However, adherence with RCWs is low, which is a serious concern given that low
adherence predicts poor DFU healing. There is an urgent need to address factors that hinder adherent use
of RCWs to promote DFU healing. Our long-term goal is to optimize offloading adherence (OA), and
subsequent DFU healing outcomes, by considering not only how much the device offloads the DFU, but also
how much the device’s design impacts the patients’ experiences with the device. The objective of this proposal
is to provide pilot/feasibility data to inform a definitive randomized controlled trial (RCT) that will evaluate the
impact of existing RCW designs on OA and DFU healing and, secondarily, will facilitate development of a
predictive model to guide patient-specific prescription of offloading devices. Our working hypothesis is that
healing outcomes with a given RCW will be predicted by objective, biomechanical markers of RCW usability
(e.g., measures of stability) and by RCW-induced changes in patient-reported factors, with the predictive
relationship mediated by the effect of these measures on OA. We will consider three specific aims to achieve
the objective and provide evidence to support our hypothesis and our ability to conduct a larger follow-up
RCT: Aim 1: To examine the feasibility of conducting an RCT to evaluate the effects of RCW form on OA and
DFU healing; Aim 2: To collect preliminary data to quantify the effect of RCW form on biomechanical markers
of usability and patient-reported adherence factors in individuals with active DFU; and Aim 3: To collect
preliminary data to evaluate the strength of associations between OA and both biomechanical markers of
usability and patient-reported adherence factors. Across two study centers, participants will be randomized
to use one-of-two RCW designs for four weeks in conjunction with weekly standard-of-care treatment.
Throughout treatment, OA will be monitored using a novel dual accelerometer method and DFU healing will
be quantified via planimetric wound area measurements. At the start of treatment participants will complete a
series of surveys to assess patient-reported factors (e.g., depression). Patients will repeat surveys at the end
of treatment and also perform several tests within a motion capture lab to assess aspects of RCW usability
(e.g., stability & energetic costs of walking). The contribution of this work will be significant as it represents
the next step in a continuum of research expected to improve DFU healing rates and reduce DFU
complications including amputation, their associated medical costs and negative impact on well-being. The
proposed study is innovative as it challenges current practice and guidelines by taking a patient-centered
approach to DFU healing, which considers an offloading devices’ impact on the patient experience, rather
than solely considering the devices’ functional offloading capacity.
