Charcot neuroarthropathy, often referred to as Charcot Foot,
is an uncommon but devastating disorder of the bones and joints in the foot and
ankle. Most commonly Charcot Foot is
seen in diabetic patients with neuropathy, but it has also been described in
patients with neuropathy of other causes.
Charcot foot is characterized most frequently as a red, hot,
swollen foot. It is typically painless,
as the patient is neuropathic. Charcot
foot is often misdiagnosed as gout, cellulits, or deep venous thrombosis
(DVT). This usually happens in a primary
care or emergency setting, where the clinician may not have a high suspicion
for Charcot foot. The consequences of a
missed diagnosis or delayed treatment include a bony deformity, which can lead
to ulceration and subsequent infection.
Thus, early diagnosis and initiation of treatment by a trained foot and
ankle specialist is essential.
The “rocker-bottom” deformity is typical of Charcot foot
that has affected the midfoot, as is the case with the majority of
patients. This refers to an increased
convexity of the bottom of the foot that is the result of excessive midfoot
collapse. When this happens, bone can
protrude, which causes increased areas of pressure on the skin. This increased pressure leads to ulceration
if not addressed.
The pathophysiology of Charcot foot has been debated in the
past, however current practitioners generally agree on the cause as a
combination of neurovascular dysregulation and trauma to the foot or ankle as
the inciting event. The neurovascular
dysregulation causes increased blood flow to the feet, which can “wash out”
some of the bone density, making the bones and joints of the foot susceptible
to injury. Trauma may be in the form of
a singular acute event, such as a fracture, but may also be from repetitive
microtrauma from a previously existing foot deformity or a poorly fitting pair
of shoes or a sudden increase in activity.
The uncontrolled inflammation associated with Charcot foot causes an
increase in osteoclast activity, the cells responsible for degrading bone.
Diagnosis of Charcot foot is made mostly as a clinical
diagnosis. The foot will appear red,
hot, and swollen, and there may be a significant temperature difference between
the feet. X-rays are taken, but may only
show subtle changes in bone quality and joint alignment if it is very early in
the disease. MRI can also be used to
examine the bones and joints of the foot or ankle, but is not necessarily
diagnostic of Charcot foot. This is
because the Charcot foot may look very similar to osteomyelitis, or an
infection of the bone. However, the
information provided by imaging studies such as x-rays and MRI can help the
clinician in diagnosing Charcot foot.
The most important aspect of treatment for Charcot foot is
offloading of the affected foot. This
means that there is no weight placed on the foot. This can be done by casting with either
plaster or with a removable cast. Some
patients may be able to use crutches or a walker while the cast is on, however,
for many patients a wheelchair is recommended.
This is due to the fact that excessive pressure on the unaffected site
may lead to increased trauma to that side, thus possibly initiating a Charcot
foot on the other side. Approximately
30% of patients affected by Charcot foot will go on to develop Charcot foot on
the opposite side.
Medical treatment with bisphosphonates, drugs traditionally
used to treat osteoporosis and some other disease of bone, has shown to be of
some benefit to patients in some small study groups. These drugs may include pamidronate (Aredia)
or alendronate (Fosamax). Treatment with
intranasal calcitonin spray has also been used.
Calcitonin is a naturally occurring hormone that helps to regulate
calcium and bone density in the body.
Additionally, some doctors have used anti-inflammatory medications in an
effort to restrict some of the uncontrolled inflammation associated with
Charcot foot.
Surgical treatment can also be used to help patients with
Charcot foot. For patients with advanced
deformities related to Charcot foot, surgery can be used to establish a more
normal appearing foot, which can then be placed in a customized shoe or Charcot
restraint orthotic walker (CROW). The
goals of surgery on the Charcot foot are to heal any current ulcers, prevent
future ulceration and infection, and to fit the patient to a customized
device. These devices are generally worn
by a patient with Charcot foot at all times, and are considered to be lifelong
devices.
Charcot foot continues to be an area of interest and
research for many podiatric surgeons, and is an extremely debilitating and
devastating syndrome. The patients who
develop Charcot foot need a lot of attention and counseling regarding their
foot deformity, and adherence to medical and surgical treatment plans is
essential for healing and for positive outcomes. Charcot foot remains a difficult problem to
treat, however, advances in the understanding of the syndrome and advances in
technology have made for better outcomes.
Central Florida Foot & Ankle Center, LLC
101 6th Street N.W.
Winter Haven, FL 33881
Phone: 863-299-4551
www.FLFootandAnkle.com
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