The early symptoms might seem harmless enough.
One foot feels a little warmer than the other. But redness, swelling and pain follow. Bones weaken and fracture. The ankle joint dislocates and collapses. The shape of the arch sags from convex to concave. Walking becomes extremely painful and difficult, if not impossible.
The debilitating condition is called Charcot arthropathy, or Charcot foot. A crippling deformity linked to diabetes, especially in morbidly obese patients, Charcot foot is on the increase nationwide.
Like diabetes itself, severe cases of Charcot foot can lead to amputation.
Statistics show that morbid obesity and diabetes are increasing. Approximately 62% of American adults with type 2 diabetes are obese and 21% morbidly so, according to study results published in the Journal of Diabetes and its Complications. Charcot foot is most common among morbidly obese diabetic patients.
In addition, the CDC reported that more than 29 million Americans — 9.3% of the population — have diabetes.
“Since Charcot foot is more common in morbidly obese diabetics, and the incidence of diabetes and morbid obesity are increasing, [Charcot foot] is likely increasing,” Michael Pinzur, MD, FAAOS, orthopedic surgeon at Loyola University Medical Center and professor in the Department of Orthopaedic Surgery and Rehabilitation at Loyola University Chicago Stritch School of Medicine, told O&P News. “When identified early, the process can be aborted with immobilization. When deformity develops, surgical correction is often advised.”
Charcot foot is the end of a downward spiral. Patients with diabetes who are obese are at increased risk of peripheral neuropathy. Patients with neuropathy are at a greater risk of developing Charcot foot. In turn, both conditions can lead to the loss of the foot.
Understanding the cause
Erick Janisse, CO, CPed, clinical director of pedorthics at Orthotic and Prosthetic Design in St. Louis, suspects Charcot foot is becoming more prevalent nationwide because he is seeing more patients with Charcot foot in his practice.
“I would expect all orthotic and pedorthic clinicians to see an uptick in Charcot patients as the type 2 diabetes epidemic rages virtually unchecked,” Janisse said, adding, “There are well over 100 documented conditions that can cause peripheral neuropathy and most of them can also lead to Charcot foot.”
Janisse said there are two principle theories about what causes Charcot foot: neurotraumatic and neurovascular.
The neurotraumatic theory asserts the patient has received trauma to the foot but remains unaware of the problem due to sensory neuropathy. Over time, the untreated damage progresses to the foot bones and joints.
Meanwhile, the neurovascular theory posits the underlying condition leads to autonomic neuropathy, which creates increased blood flow to the extremity, ultimately leading to osteopenia.
Janisse believes the root of Charcot foot is a combination of both neurotraumatic and neurovascular causes.
“Essentially, the foot receives an insult and a fracture occurs. Due to the sensory neuropathy, the patient continues walking on it and causes further damage,” he said. “The body’s reaction to the injury is to increase blood flow to the area to promote healing and new bone growth, but due to the presence of autonomic neuropathy, the body does not know when to ‘shut off’ the flow and the bones soften and weaken and the progress of the destruction is accelerated. Motor neuropathy plays a role, too, wherein the intrinsic muscles of the foot become compromised and do not function normally, which results in the joints of the foot seeing abnormal forces and stresses.”
While Charcot foot stems from neuropathy, several conditions can trigger neuropathy, according to Seamus Kennedy, CPed, president and co-owner of Hersco Orthotic Labs in Long Island, N.Y.
However, “by far the most common of these is diabetes,” Kennedy said.
That is because consistently elevated blood sugar can lead to peripheral nerve damage for diabetic patients, resulting in a loss of sensation in the extremities.
“Once this occurs, a patient’s foot becomes vulnerable,” he said. “Then even a mild trauma or overloading can be the triggering event, but the patient will not respond as they usually do not feel anything.”
Thus begins a cycle in which fractures and dislocations can happen, he added. “The foot can begin to lose shape as the bones no longer align correctly, uneven pressure can arise and the midfoot begins to collapse. In this stage the foot structure itself is unstable and liable to permanent deformity. Left unchecked the foot may develop open wounds that are slow to heal.”
Kennedy maintained that prevention is the best policy with Charcot foot.
“Patients need to understand the seriousness of this diagnosis,” Kennedy said. “Once neuropathy has developed it is very important to protect the foot and ankle from trauma and breakdown. The provision of well-fitting shoes with sturdy counters and proper toe boxes has been proven to protect the feet of diabetic patients with neuropathy. In addition, multi-durometer total contact insoles can even out plantar pressures.”
He said Charcot arthropathy has been outlined in three stages, depending on the progress of the condition. The stages, according to the American Orthopaedic Foot and Ankle Society (AOFAS), are:
- Stage 1, the acute stage, identified by “marked redness, swelling, warmth; early radiographs show soft tissue swelling, and bony fragmentation and joint dislocation may be noted several weeks after onset.”
- Stage 2, the coalescence, identified by “decreased redness, swelling and warmth; radiographs show early bony healing.”
- Stage 3, the chronic stage, identified by “redness, swelling, warmth resolved; bony healing or nonunion and residual deformity are frequently present.”
Kennedy said that more recently, practitioners have identified a “Stage 0,” or the early sign that breakdown could be imminent.
“Any patient with neuropathy who presents unilaterally with a clinically warm or swollen foot should be immediately referred to a physician,” he said. “Once a patient has been diagnosed with Charcot foot they need very special care. As long as the foot remains unstable the patient must continue to see their DPM or MD regularly.”
Physicians or podiatrists often will prescribe direct off-loading through total contact casting or orthotic walker boots, Kennedy said. Once stability has been restored, he said, the patient could benefit from extra-depth shoes, custom insoles or custom-molded shoes, as well as pedorthic enhancements such as rocker soles, flares or internal depressions in the midsole of the shoe. These items “can all help relieve pressure and protect the at-risk foot.”
Janisse said the options for a pedorthist working with active Charcot foot are limited. Instead, the pedorthist should attempt to prevent further complications “such as ulcers under new bony prominences on the plantar surface of the foot,” he said. “We also try to normalize pressures and bending stresses on the foot, especially through the old Charcot area to prevent new injury.”
He said pedorthists should keep two treatments in mind for patients with Charcot foot: the use of orthotics to prevent some of the stress created by the bending of the midfoot or hindfoot, and/or working with an orthotist “to provide to more proximal device that can offer axial offloading in addition to the transfer of stresses.”
According to the AOFAS, patients who show instability in the early stages of Charcot foot may need surgical treatment in the form of open reduction and internal fixation or fusion. Late stage surgical treatment may include osteotomy and fusion, which corrects deformity, or ostectomy, defined as “removal of bony prominence that could cause an ulcer.”
Additionally, Pinzur has popularized a promising alternative form of surgery for patients with Charcot foot. The operation features an external frame called an Ilizarov circular external fixator. Made of stainless steel and aircraft-grade aluminum, the device holds the disarticulated bones back in their proper places, thus enabling the foot to heal properly.
Pinzur had performed more 500 operations on Charcot foot patients and 400 using the frame. He said so far, 90% of his patients are able walk again in diabetic footwear.
Heretofore, the most common way to treat Charcot foot was to encase the foot in a plaster cast. Drawbacks to casting are two-fold, according to Pinzur. First, bones do not necessarily heal in the correct positions when casted. Second, many morbidly obese patients cannot walk with one leg in a cast.
The Ilizarov frame is designed to eliminate the need for a cast and a leg brace. The frame has three rings that encircle the lower calf and foot. Each ring is fitted with stainless-steel pins and aircraft-grade aluminum that attach to the foot, thus securing the bones after surgery.
The device stays on the patient for between 10 weeks and 12 weeks after surgery. During that period, the patient often can walk and put weight on the foot. After the Ilizarov fixator is taken off, the patient is fitted with a walking cast for a period between 4 weeks and 6 weeks and eventually graduates to a removable boot or to diabetic footwear, Pinzur said.
Time to heal
Regardless of which option is used, healing may require several months, according to the AOFAS. Patients with Charcot foot may need twice the amount of time to heal after surgery as patients without diabetic foot issues. For Charcot foot and ankle surgery, healing may need 6 months of protection, as well as subsequent use of orthoses.
Patients should also be aware that Charcot foot can recur or flare up. One potential complication is the formation of plantar midfoot ulcers associated with the “rocker bottom foot.” Other possibilities to be aware of include deformities in any area of the foot or ankle and ulcers which can quickly become infected. Additionally, some Charcot joints can heal with fibrous tissue, which may lead to gross instability or “floppy foot” — another cause of ulcers. An infected ulcer on a patient with Charcot foot can lead to amputation or even death.
Bracing for a patient with Charcot foot can includes a gauntlet AFO, insoles or custom molded shoes, said Rob Sobel, CPed, owner of Sobel Orthotics and Shoes in New Paltz, N.Y. and president of the Pedorthic Footcare Association (PFA). “It depends upon the deformity, range of motion, foot position and the patient,” he said.
Charcot foot can be secondary to an acute injury, Sobel added.
“Sometimes it is just a noticeable episode of redness, swelling and heat with a noticeable deformity,” he said.
Sobel sees a number of patients with Charcot foot.
“We do custom molded shoes for many of the podiatric groups in the area when a patient has Charcot,” he said. “We will also do a gauntlet AFO if that is the better treatment modality. There is also the option of doing a ‘hybrid’ foot orthosis that is both accommodative and functional and allows us to control and accommodate foot motion and position, with an either extra or supra-depth shoe.”
Sobel suggested the increase in patients with Charcot foot patients is “probably because the health care system insists on patients being moved through faster and faster, with less time to be educated on the things to look out for, or the possible hazards of their diabetic condition.”
Sobel said patient education is a big part of the treatment regimen.
“We try to educate every patient as to what to watch out for, and when to contact their [podiatrist] or [primary doctor] so they do not suffer an unnecessary injury. Diabetic patients are the most likely to develop Charcot foot, and we make every attempt to educate the patients what to look out for so they do not let something go without intervention.”
Dennis Janisse, CPed, owner of the Milwaukee-based National Pedorthic Services, said patients need to understand the potentially detrimental effects of Charcot foot.
“It involves the function or lack of the sensory, motor and autonomic systems. With these three nerve systems being affected it sets the stage for very serious consequences,” he said. “The resulting feet can be challenging, with severe deformity, rigidity or hyper-mobility, all needing the skilled and expertise of the certified pedorthist or orthotist.” – by Berry Craig
- 2014 National Diabetes Statistics Report. CDC. Available at www.cdc.gov/diabetes/data/statistics/2014statisticsreport.html. Accessed Oct. 1, 2015.
- Charcot Arthropathy. American Orthopaedic Foot and Ankle Society. Available at: www.aofas.org/footcaremd/conditions/diabetic-foot/Pages/Charcot-Arthropathy.aspx. Accessed Sept. 30, 3015.
- Kramer H, et al. J Diabetes Complicat. 2010;doi:10.1016/j.jdiacomp.2009.10.001.
- Loyola Surgeon Reports Successful Treatment of Charcot Foot, a Debilitating Diabetes Complication. [news release]. 2015; Loyola University Health System. Accessed Sept. 30, 2015.
Disclosures: Dennis Janisse, Erick Janisse, Kennedy and Sobel report no relevant financial disclosures. Pinzur reports he is a consultant for Smith & Nephew and a lecturer for Stryker and Smith & Nephew.