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Jean-Martin Charcot, a scientist in the late nineteenth century, first described the deterioration of ligaments and joint surfaces now known as Charcot’s joint or Charcot disease. Charcot foot, or neurogenic arthropathy, is a usually painless, rapidly progressive degeneration of one or more joints in the foot, as well as the surrounding ligaments, tissues and cartilage. According to an article titled, “The Charcot Foot: Management of Diabetic Charcot Arthropathy,” more than 24 different diseases are associated with Charcot foot, but type 2 diabetes with mixed peripheral neuropathies is the primary cause. Due to long-standing neuropathy, there is a loss of sensation and decreased proprioception. A loss or absence of sensory nerve functions prohibits the person from feeling temperature, texture or pain. Decreased motor nerve fibers inhibit gross motor movements such as walking. Consequently, the person may be unaware of a minor trauma, such as a sprain. The person continues to walk on the foot, causing additional traumas leading to joint dislocations, bone erosion, muscle weakness and deformities. Presentation and MisdiagnosisThe presentation of Charcot foot is a hot, red, swollen foot. Often, the disease does not show up on a radiograph until it reaches the destruction phase. Misdiagnosis in the early stage is common. “We see people referred to us with a diagnosis of osteomyelitis, but there is no break in the skin,” said Judith Pfleegor, PT, CPed, director of the diabetes foot clinic, Mount Nittany Medical Center, State College, Pa. “If they have a hot, red, swollen foot and there is no portal for bacteria to enter, Charcot foot needs to be considered.” The disease can also be mistaken for sprains, deep vein thrombosis, or infections such as cellulitis or osteomyelitis. According to Bret Ribotsky, DPM, FACFAS, FACFAOM, Boca Raton, Fla., diagnosing Charcot foot sometimes requires opening up the area, taking a biopsy and looking for shards of bone in the fluid. If pieces of bones are present, it is Charcot foot, he said. The Process of Charcot FootRibotsky prefers to use an analogy in describing the process of Charcot foot.
Imagine you are at home and you slam one of the doors in the house, he said. If you slam the door hard enough, the whole room starts to shake. Now imagine you are deaf and you do not hear the room shake, so you keep slamming the door. Eventually, the framing around the door breaks loose. If you do not know it is breaking loose it continues to fall apart until eventually the door falls off. “The similarity of the door-slamming scenario and diabetic Charcot foot is that the bones, usually the tarsals or metatarsals, start to break,” said Ribotsky. In its attempts to splint the fractures, the body rushes blood to the area, causing swelling. The swelling decreases joint mobility somewhat. “It is almost like an internal cast,” Ribotsky said. The overabundance of blood to the area washes away the calcium in the bone. The bone is absorbed faster than it can be replaced. “The comparison of the blood rushing to the area could be a hurricane washing away the sand on the shore,” said Ribotsky. One of the big fallacies concerning the diabetic foot, said Pfleegor, is that the lower extremities routinely have poor circulation. “We do not find this to be true,” she said. “People with Charcot foot generally have excellent circulation. This is apparent given all the blood that rushes to the foot.” However, these patients do have neuropathy and need to understand that both the vascular and nervous system can be affected in the setting of diabetes, but not always simultaneously, said Pfleegor. Nancy Elftman, CO, CPed, of Hands On Foot Inc., La Verne, Calif., added that the person will keep walking on the foot not knowing they have multiple microtraumas occurring on the joint surface. “A hundred microtraumas become thousands and by that point, the body is absorbing bone and not depositing new bone,” she said. Stages of Charcot Foot
According to an article written in the Journal of Bone and Joint Surgery, there are three stages in the development of Charcot foot. Stage one is the destructive phase resulting from repetitive trauma resulting in fractures. As the inflammatory process continues, hyperemia and bone resorption occur. As mechanical destruction progresses, stage two with continual hyperemia and inflammation leads to loss of bone. Stage 3 is continued disintegration of the joint and the surrounding tissues. For treatment to be successful and healing to take place, the destructive phase must be stopped with immobilization. Risk FactorsCharcot foot occurs most often in people with long-standing, usually severe type 2 diabetes and pre-existing neuropathy. While peripheral neuropathy takes years to develop, the progression of Charcot foot can happen in weeks or months. According to Ribotsky, given that many diabetics are obese, most patients with Charcot foot are overweight. However, he does see patients with the disease who are thin. “I have seen many patients who are ex-cheerleaders,” Ribotsky said. “They are slim and tend to be a little more osteoporotic.” Activity level is also a factor, he said. An active 25-year-old person with peripheral neuropathy, for example, is at a higher risk of developing the disease than an 85-year-old who is less active. There are other diseases associated with Charcot foot, such as Hansen’s disease, different forms of arthritis or any other disease combined with peripheral neuropathy. Treatment and ManagementIt is imperative to rule out infection and recognize and treat Charcot foot in the acute stage. The foot should be immediately immobilized, bearing no weight. A total contact cast is used to keep the foot stationary. If the deformity is not severe, removable cast boots can be used, said Dennis Janisse, CPed, president and chief executive officer of National Pedorthic Services in Milwaukee.
“After 2 to 4 months, the disease process burns out,” Janisse said. “You never get any joint spaces or a normal foot, but the person will hopefully have a block of bone that is relatively easy to put a shoe on for protection.” Pfleegor added that the cast keeps the foot aligned in a relatively normal position. The bones will still break down and shift around a little, she said, but the cast will prevent the bones from becoming markedly misaligned. “We usually cast anywhere from 3 to 9 months, with cast change frequency being dependent on the leg volume,” she said. Periodic radiographs are done throughout the course of casting. When the bones become stable and the skin temperature is closer to the contralateral limb temperature, the cast is removed and the patient is placed in a less restrictive device. The biggest complication with casting is skin breakdown, said Pfleegor. “Casting works well, but it is total contact by nature,” she said. “There is minimal padding and the patients do not have adequate feeling.” With the use of skilled technicians, appropriate cast change intervals and a reduction in the patient’s activity by 50%, cast complications are usually minimal. “For the treatment of Charcot, the benefits of casting far outweigh the risks,” Pfleegor said. According to Elftman, because the edema decreases significantly after the first week in the cast, the cast has to be changed. The patient is not put into a shoe when casting is complete. Instead, it is a gradual process whereby they spend some time in a splint before being fitted for a shoe. “If the management of Charcot foot is not well thought out and the abnormalities responsible for the condition are not well thought out, the patient can lose his or her leg or even life,” said Ribotsky. The disorder is complex and multifactorial, requiring coordination of care from several disciplines. Ribotsky said he tries to make sure a family member accompanies the patient, because patients can be forgetful. “I have had patients remove their own casts,” he said. “Noncompliance can be an time bomb resulting in the loss of a limb.” It is important to educate the patient that they do indeed have a disease process. “Then they can go out and be ambassadors for other people,” he said. Complications
If Charcot foot is not treated appropriately and quickly, complications develop. In the advanced stage, deformity can occur from joint displacement or dislocation, as well as bony overgrowths. Fractures may cause the tarsal bones to collapse resulting in an outward bowing of the arch or rocker foot. “Often, the areas that are involved in the biggest deformities are the hindfoot, ankle or midfoot,” said Janisse. “These are some of the most challenging deformities we have in pedorthics.” Ribotsky added that deformity occurs most often in the medial aspect of the joints of the feet in the tarsal bones. Other complications may be calluses and ulcerations. Ulcerations develop from bony protrusions rubbing against the shoes. If the ulcers become infected, amputation may be necessary, said Janisse. Surgery and MedicationsMedications are sometimes used to turn off the body’s osteoclast cells, which are responsible for bone resorption, said Ribotsky. “If the bones and structures have become imbalanced, broken and misaligned, stabilizing the foot may be necessary through surgical intervention,” Ribotsky said. A combination of tendon balancing and surgical fusion of the joints may be performed. In Pfleegor’s clinic, surgery is considered only if standard treatment does not work. Orthotic TreatmentTo prevent ulcers on bony protuberances, an orthosis is prescribed to redistribute the weight. “Also, when one foot is breaking down, we cannot forget about the other foot,” said Ribotsky. “The other foot often needs an orthotic or some sort of device to balance and protect it, because the worst scenario can happen and the patient loses the other leg.” A lot of people forget about the nonsymptomatic leg, Ribotsky said. What About the Other Foot?Rarely do clinicians see a patient who has a Charcot process ongoing in both feet simultaneously, said Ribotsky. Why does it tend to be unilateral? He believes it is due to a traumatic episode occurring combined with a tightness in one of the muscle groups. “This seems to be the straw that breaks the camel’s back,” he said. Elftman said she has seen many patients who have Charcot foot on both feet, a few of them having the disease on both feet simultaneously. Once the person has it one time, they are prone to getting it again in other joints that receive increased stress, she said. Pedorthist’s Role
The pedorthist plays an important role in the management of Charcot foot. After the Charcot is resolved, the pedorthist will make the appropriate shoe to accommodate the foot. Properly fitted shoes will protect the foot from ulcerations, replace motion and provide shock absorption. In severe deformities, the shoe will be custom made with perhaps a molded foot bed. With bony deformities, an increased depth, wide width shoe may be constructed by modifying an off-the-shelf shoe. A rocker bottom foot may be used for midfoot Charcot. “We can usually accommodate this in a shoe, but we have to widen the instep,” said Elftman. “We will need to make a total contact insert and a shoe that will accommodate the foot.” A foot orthosis in the shoe will also protect the plantar surface of the foot, added Janisse. “If the patient has a past history of ulcerations, we would most likely fabricate rigid outsoles,” noted Pfleegor. Frequency and StatisticsAccording to Ribotsky, Charcot foot occurs in 1% to 2% of the diabetic population. “I have a referral-based practice so I probably see it more often,” he said. Elftman sees patients with the disease quite a bit in her practice as well. “They say Charcot foot is not common,” said Elftman. “But you have to remember it is often misdiagnosed.”
Other DisciplinesThere can be several disciplines involved in the management of Charcot foot. Since most of the patients have diabetes, they often have other medical problems. They may be seeing an internist, endocrinologist or cardiologist. A vascular surgeon or even plastic surgeon may be involved in care. Physiatry or physical therapy assists with mobility, wound care, casting and strengthening exercises. Home care assessment and nursing may also help with wound care. Prevention
Ribotsky noted that all patients with a midfoot Charcot collapse have some degree of ankle equinus. He believes that as diabetics start to become neuropathic, their sense of balance becomes compromised. They tend to walk with their feet slightly wider apart. “Walking like this transfers the weight from being completely centered over the foot to the medial bones,” he said. “The internal aspects of the bones then bear excessive weight.” Combine that with the patient’s inability to feel the joints and it sets up a cascade of events that get progressively worse. It is therefore imperative that people with neuropathic feet have a thorough evaluation for muscular imbalance, said Ribotsky. Early DetectionThe big push is early detection, added Pfleegor. She said she has had patients with questionable Charcot who were casted for about a month. They see no changes on the radiographs, but in the interim, the temperature and swelling of the foot has decreased. “Maybe they did have a sprained ankle,” she said. “Some people may think this is overkill, but if we do not protect the foot and they keep walking on it with a sprained ankle, it may progress to Charcot. We find prevention is extremely important.” For more information:
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