Charcot Arthropathy is a destructive breakdown of joints within the foot (usually the midfoot or ankle) in patients with abnormal sensation such as often occurs in patients who have diabetes. When it initially occurs the foot is usually swollen, red, and warm and as such it can be mistaken for an infection. The condition is named after Jean Marie Charcot (1825-1893) who described the collapse of the bones of the foot in patients who had lost feeling in the feet from advanced syphilis. Treatment is initially non-surgical and involves minimizing weight-bearing through the foot by using a total contact cast or walker boot until the bones in the foot become more stable. This often takes 6-12 months or more. The goal of treatment is to create a stable foot without any deformities that can lead to pressure points and a resulting diabetic ulcer. Surgery is reserved for feet that have developed symptomatic foot deformities that can not be addressed non-surgically. Surgery on patients with Charcot foot deformities is often associated with a high complication rate.
Patients with an acute (sudden onset) Charcot arthropathy of the foot will often present with swelling and redness around the midfoot or ankle. This occurs in patients with diabetes or other conditions that lead to altered sensation in the foot. This condition can be painful, but is commonly not as painful as it would be if they had normal feeling. Some patients may have had a period of increased activity leading to repetitive loading stress through their foot or ankle or they may have had a mild injury.
Charcot arthropathy can look similar to an infection in the foot and is commonly mistaken for this.
Charcot arthropathy is an abnormal response of the body that can lead to collapse and even disintegration of the bones in the foot and ankle. The body dramatically increases the blood flow to the area leading to the redness and swelling and increased rate of bone reabsorption. The three common locations include the tarsal-metatarsal [Middle of the foot] joints, the transverse tarsal joint [Hindpart of the foot just in front of the ankle], and the ankle joint. This is a particularly frustrating and debilitating condition because it can take 6-12 months or more to resolve. Furthermore, when it does get better, the foot may have collapsed and changed shape. The resulting deformity can put the patient at risk to develop an ulcer over new prominent bony areas.
Observation of the foot usually shows swelling and redness. This redness will usually resolve or improve with elevation (above the heart). This makes it different than a skin infection which will often remain red when elevated. It is important to look for breaks in the skin, as this may suggest infection instead of Charcot arthropathy. Although the two can be present at the same time, it is usually one or the other.
It is important to look for deformity. The goal of treatment is to prevent deformity so noticing early deformity is crucial to keep it from getting worse. As this process usually happens in people with loss of feeling in the foot, examination will often demonstrate abnormal (but not completely absent) sensation. However, Charcot arthropathy often happens before the patient has noticed any changes in the sensation of the feet. Blood supply to the foot should also be assessed (as with any patient), although in Charcot, adequate blood supply is rarely the problem
It is also important to look at the other foot. Charcot arthropathy on one foot greatly increases that chance that the patient will develop a similar situation on the other foot. This can happen at the same time, but more commonly happens sometime after the other foot gets better. Diabetic patients should always be checking their feet regularly for problems.
Regular x-rays are important. If caught early, these x-rays may not show any abnormalities. Sometimes they will show a decrease in bone density (osteopenia) or a break in the bones involved. If the process has progressed, the x-ray may show deformity of the foot or ankle.
CT scans can be helpful to look at a more detailed picture of the collapse, but is not often necessary unless surgery is planned. .
Bone Scans can sometimes be helpful to sort out whether the problem is infection or Charcot arthropathy.
When detected early, treatment involves a period of non-weight bearing or limited weight-bearing in either a special cast often called a total contact cast or a diabetic removable boot (often called a CAM boot or walker boot). Later in the process, when the bones have started to stabilize, the patient can walk more and put increasingly more weight on the leg.
There are devices that are available such as rolling knee walkers, which can help keep the weight off the bad foot while allowing patients to be mobile and not over-loading the better foot.
There are some studies that suggest that the use of bisphosphonates (anti-osteoporosis medications) may be helpful in treating Charcot arthropathy by trying to limit the activity of the cells that eat away bone.
If a severe deformity has occurred or the foot or ankle has become unstable, then surgery may be recommended.
Surgery ranges from simple removal of prominent bone [exostectomy] to reconstruction of the foot with fusion of the bones after the deformity is corrected. This can involve the use of screws and plates, or rods that go inside the bone, or pins that come out of the bone and skin and attach to a frame on the outside of the foot and ankle.
The goal of surgery is to end up with a foot that is stable, can bear weight, and can fit in a shoe or brace and not have problems with ulcers developing over prominent areas of bone. Most surgical procedures that involve fusion will typically require a long period of not putting any weight on the foot or leg for 3 months or more.
Surgery for Charcot arthropathy is associated with significant risks. These include increased risks of:
- Infection and wound healing problems (which is commonly a problem with diabetic patients).
- Non-union: There is an increased risk of bones not healing together because patients often don’t realize how much pressure they are putting on the foot during the healing process. However, a failure of the bone to heal is not necessarily a failure of treatment. If the goals listed above are met, then the surgery was a success.
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