Repetitive plantar stresses from walking can injure the soft tissues of the feet resulting in skin breakdown and foot ulcers in people with diabetes mellitus and peripheral neuropathy. How the tissues respond to the imposed stresses depends upon the absence or presence of several factors. This dissertation examines specific modulating factors that impact the effect of these stresses on the neuropathic foot and how the applied stress relates to these factors.

Chapter 2 provides evidence for the use of therapeutic footwear and orthotic devices as extrinsic factors to decrease potentially harmful stresses and strains to the plantar aspect of the foot. Improved understanding of how strain plays a role in distributing plantar forces may result in improved designs for pressure reducing footwear and orthoic devices.

Chapter 3 investigates the relationship between activity level and the skin temperature response of the foot to the stress of walking. The results of chapter 3 suggest that people with diabetes and peripheral neuropathy who regularly have high amounts of activity may have improved microvascular responses to stress compared to those with diabetes and neuropathy who are sedentary.

Chapter 4 examines the potential benefit of peak pressure gradient and peak maximum shear stress when examining patients with diabetes and peripheral neuropathy and high plantar pressures. Peak pressure gradient and peak maximum shear stress were more discriminatory in assessing risk of skin breakdown between groups of patients with and without a history of ulceration and diabetes and peripheral neuropathy.

The results of these studies provide information concerning how the insensate foot responds to stress and suggests means to decrease the potential for injury to these tissues. Further research is needed to better understand the mechanisms of soft tissue injury in the neuropathic foot and the optimal interventions to prevent foot ulcers in people with diabetes and peripheral neuropathy.