The diabetic foot involves two associated but independent challenges.  The most common problem is development of skin ulcers from excessive pressure or injury, the second is the inability of the diseased joint and ligament tissue to protect the foot from collapse caused by stresses of weight bearing or injury.  Microvascular changes in the blood supply to the skin and soft tissue beneath calluses make the foot especially vulnerable to pressure.  The protective fat is lost, and the skin growth fails so the tissue breaks down and ulcers develop.  The mechanical forces of weight bearing then can lead to even further damage.
With the loss of sensation, position sense, and proprioception, the foot loses its ability to adjust to stress demands such as strains and sprains.  Thus, these minor injuries and, occasionally, more serious injuries such as fractures go unnoticed.  Without pain, the patient is not protective of the injuries, so trauma continues, soft tissue and joint and bones injuries fail to heal, and diabetic osteoarthropathy develops.  This destructive arthritic-like process has been named "Charcot foot," which refers to bony abnormalities associated with diabetic neuropathy.

The role of the custom orthotic in the case is to relieve pressure from the ulcer and ulcer-prone areas of the skin and to support and protect the biomechanically disabled internal structure of the Charcot foot.