Peripheral neuropathy is the damage or death to the nerves in the peripheral areas such as your legs that are either caused by:
- Vitamin deficiency - B12 or folate
- Autoimmune disease - rheumatoid arthritis, Guillain-Barre syndrome, lupus
A chacot foot is characterized as a catastrophic deterioration in the joints of the midfoot. Because diabetes in its later stages can result in peripheral neuropathy in the foot and lower limb, a loss of pain sensation and proprioception combined with continual pounding of the joints in the foot can produce this deformity. When this occurs, the body does not register the minor traumatic event and the end result is a total collapse of the midfoot. This is known as a rocker bottom foot.
For the 50 percent of people who have a charcot foot can remember the minor traumatic event such as an ankle sprain, that started the development of their charcot foot. But for the other 50 percent, the development of their charcot foot onstetted when a foot infection developed, along with hyperaemia (increased blood flow to the infected area).
A typical case of signs and symptoms to look for with the development of a charcot foot would be:
- Later in age
- Type 2 Diabetes
- Signs of peripheral neuropathy
- No pain or sensation in foot
- Doppler test performed and result was intermitted sensation
- Before collapse, redness and swelling in foot with no pain
- Difficulty putting shoes on because of swelling
- No radiography was done prior to the development of the charcot foot to rule out the beginning of the deterioration
- Deformity in foot - longitudinal arch collapse resulting in rocker bottom
The Doppler test is performed on the plantar surface of the foot around to the dorsum foot and up the lower limb. With a monofilament, light touches to the foot are performed to check for the presence of sensation. If sensation is not felt, a CT or MRI may be the next step to rule of the start of the rocker bottom deformity.
There is no doubt that poor foot mechanics play a major role in the progression of the charcot foot. However, once the foot has become effectively a rocker bottom, the progression stops and the foot is permently in it new deformed development. At this point a pair of custom made insoles need to be fabricated as well as a pair of custom made shoes need to be made as well.
The custom made foot orthotics have to be designed to offload the dropped navicular or midfoot bones from the rocker bottom deformity. This type of custom made foot orthotic does not fit into a typical store bought shoe and from here, a pair of custom made shoes now need to be deep enough to fit the rocker bottom deformity as well as assist in offloading the midfoot.