It is estimated that, globally, a lower extremity amputation takes place every 30
seconds, and that 85% of these amputations are the result of diabetic foot ulcers.
Plantar foot ulcers develop, in part, due to high loading and mechanical stress to the
soft tissues of the foot. Custom standard of care insoles aim to reduce regions of the
foot that experience excessive plantar pressures by redistributing pressure to other
areas.
Limitations in the effectiveness of standard of care insoles, however, result in rates of
ulceration that remain unacceptably high. Meanwhile, a revolution in 3D printing
technologies, material properties, and digital manufacturing pipelines are enabling a
wave of innovative solutions that are improving outcomes in many areas of medicine. The
investigators aim to leverage these techniques to create novel patient-specific 3D
printed insoles with personalized metamaterials which the investigators believe will
demonstrate superior offloading performance.
Personalized metamaterials are 3D printed materials formed from lattice patterns derived
from patient specific characteristics, resulting in insoles that are uniquely matched to
the patient's needs. The aim of this study is to determine if 3D printed insoles with
personalized metamaterials reduce plantar pressures for at-risk areas of the foot better
than standard of care insoles. The investigators will manufacture three different
insoles, namely the standard of care (SC), 3D printed pressure based (3DP-PB), and finite
element optimized (3DP-FE) insoles. 3DP-PB insoles will be designed from plantar foot
shape and dynamic plantar pressure while the 3DP-FE insoles will be designed from
simulations of participant's feet interacting with different insole designs to optimize
the insole shape and metamaterial properties. In a repeated measures study, the
investigators will measure peak plantar pressure and pressure time integral for each type
of insole with a group of 25 participants who have diabetes and elevated forefoot
pressure. The investigators hypothesize that the 3D printed insoles comprised of
personalized metamaterials derived from plantar measurements (3DP-PB) will have greater
reductions in the peak plantar pressure and pressure time integral than the SC insoles
(H1).
Additionally, the investigators hypothesize that, relative to the other two insoles,
insoles optimized through patient specific finite element simulations (3DP-FE) will have
the greatest reduction in peak plantar pressure and pressure time integral (H2). To
facilitate the clinical translation of the novel 3D printed insoles the investigators
will carry out focus groups with patients and clinicians to gain their early feedback and
insights. Results from these focus groups will be qualitatively synthesized into
actionable improvements to the insoles. Novel insoles that utilize 3D printing
fabrication may provide enhanced protection from foot ulcers that frequently progress to
amputation. Moreover, digital manufacturing technologies and 3D fabrication methods have
relatively low barriers to mass production, which can greatly expedite translation into
clinics. The VA is widely recognized as a leader in health care innovation. The
development of custom 3D printed insoles that may reduce risk for amputation is
well-aligned with VA's spirit of innovation and is supported by the VA mission "To care
for him who shall have borne the battle." Reducing rates of ulceration in the Veteran
population has the potential to greatly reduce incidence of lower-limb amputations and
improve the quality of life for Veterans.
