What is Charcot Neuropathic Osteoarthropathy?
Charcot neuropathic osteoarthropathy is a condition that damages the joints. It starts with an injury to a limb that has nerve damage. This condition can lead to displacement of the bones in the foot or even fractures. It is crucial to correctly identify and treat acute Charcot (that’s when the condition is in its early stages), to prevent severe foot deformities and help maintain a stable, flat foot that can be used for walking. This review discusses the causes of Charcot, how it develops, its symptoms, and treatment options.
What Causes Charcot Neuropathic Osteoarthropathy?
Charcot neuropathic osteoarthropathy is a condition that occurs in the lower limbs and is characterized by the breaking down of bones and joints in the foot and ankle. This occurs in people with various conditions affecting their peripheral nervous system, such as diabetes. Accidents, metabolic abnormalities in the bone, and these aforementioned underlying conditions can lead to a localized inflammatory condition, causing a painful reaction in a specific area. This reaction can permanently disrupt the structure of the foot’s bones, leading to unusual pressure on the soles of the feet. Over time, these structural changes can increase the risk of developing ulcers, bone infections, and may even lead to amputation.
Charcot is a distressing condition that affects the lower extremities of patients with well-established peripheral neuropathy – damage or disease affecting the peripheral nerves. Although the condition can have many complex causes, most commonly it is related to diabetic neuropathy. Other causes include spinal cord injury, polio, leprosy, syphilis, chronic alcoholism, and syringomyelia – a disorder in which a cyst forms within the spinal cord.
Risk Factors and Frequency for Charcot Neuropathic Osteoarthropathy
Charcot disease, a condition that affects the nerves and bones, impacts about 0.1% to 0.9% of people with diabetes. It’s estimated that about 63% of these people will develop a foot ulcer, which is an open wound. Research also shows that there’s a link between higher body mass index and Charcot disease.
- Charcot disease is found in about 0.1% to 0.9% of people with diabetes.
- Of these, around 63% will develop a foot ulcer, which is an open wound.
- Higher body mass index is associated with a higher chance of having Charcot disease.
Signs and Symptoms of Charcot Neuropathic Osteoarthropathy
Charcot disease is a condition where the foot becomes red, swollen, and warm – symptoms which can sometimes mistaken for deep vein thrombosis or cellulitis. This condition often caught people by surprise, appearing suddenly and on one foot only. These symptoms might follow an ankle sprain or other activities that strain the foot. Even walking can trigger Charcot if done repetitively.
Charcot disease is sometimes confused with osteomyelitis, a bone infection that has some comparable symptoms – a red and warm swollen foot, with bone deterioration visible on x-rays. While Charcot disease and osteomyelitis are separate conditions, they can occur together. In fact, cases have shown that osteomyelitis can sometimes set off Charcot due to the waves of inflammation that the infection triggers in the body. This risk increases if surgery is performed to remove the infected bone, as both osteomyelitis and surgery stir up reactions of inflammation – just the kind of environment where Charcot disease thrives.
Changes in the foot’s bone structure after surgery can also spark Charcot disease. Any changes to the way pressure is balanced across the sole of the foot when walking, whether caused by amputations or other surgical interventions, can cause small injuries. These injuries can trigger inflammatory responses, progressing to Charcot disease, if the foot cannot properly adjust to the new pressure points.
Testing for Charcot Neuropathic Osteoarthropathy
Common ways to understand and categorize the phases of Charcot, a type of joint disease, include the Eichenholtz classification and the Sanders and Frykberg classification. The Eichenholtz classification describes the three stages of disease progression based on what doctors can see and analyze from both a clinical and imaging (or radiographic) perspective. The Sanders/Frykberg classification categorizes five common locations of Charcot in the foot.
Let’s break down these classifications to understand them better:
Eichenholtz Classification
Stage 0 – Also known as Pre-Charcot/Prodromal
During this stage, you might notice a red, hot, swollen foot but won’t see any deformation in the foot’s shape. When your doctor takes an X-ray, it would appear as normal as no changes can be observed yet.
Stage I – Also known as Development/Destruction
At this stage, you may notice redness, foot swelling, increased warmth in the foot, but no pain. An X-ray might show particles of bone at the joints, fragmentation under the joint surface, joint subluxation (partial dislocation), and/or complete fracture displacement.
Stage II – Coalescence
Here, the obvious signs of inflammation, like redness and swelling, may begin to reduce. An X-ray could show worsening of features seen in Stage 1. New bone formation can be observed along with absorption of boney debris. Large fragments of bone can be seen merging together, with hardening at the ends of bones, indicating some increased stability.
Stage III – Consolidation
In this stage, inflammation generally subsides. But due to final remodeling of the underlying bone, changes can be seen in the overall foot structure that can lead to new pressure points at risk of skin breaking down. An X-ray will show remodeling of the affected bones and joints.
Sanders and Frykberg Classification
1. Joints from metatarsal to toe joints (Metatarsophalangeal to interphalangeal joints): 15%
2. Joints where the foot and ankle bones meet (Tarsometatarsal joints): 40%
3. Joints between the navicular bone and the cuneiform bones, such as naviculocuneiform joint, navicular-cuneiform, talonavicular, and calcaneocuboid joints: 30%
4. Ankle and subtalar joints: 10%
5. The heel bone or calcaneus: 5%
These classifications provide a helpful way of understanding what is happening in each stage of Charcot disease and where in the foot it is likely to affect.
Treatment Options for Charcot Neuropathic Osteoarthropathy
The goal of treating Charcot foot, a condition that can cause swelling and instability in the foot, is to reduce permanent foot deformity and create a stable foot for walking. During the early stage of Charcot foot, it’s very important to avoid movement of the foot and to not place any weight on it so it doesn’t become deformed. This can be achieved by using devices such as crutches and wheelchairs to keep weight off the foot, or by using a special type of cast known as a total contact cast (TCC) with a controlled ankle motion (CAM) walker to help you walk while still protecting the foot. TCCs help spread and reduce pressures on the foot while allowing you to move. The hot, inflamed phase of Charcot foot, which is part of a classification made by Dr. Eichenholtz, can last for weeks. If you use these protective measures, the foot may heal its fractures in a stable position if the stress doesn’t overwhelm the healing process.
There are also medications that can help control the activity of cells that destroy bone (osteoclasts). For instance, we have medicines called bisphosphonates and calcitonin supplements. Bisphosphonates may help during the early stage of Charcot foot as they can slow down osteoclasts from absorbing bone. Calcitonin also works in a similar way. Other medicines include pamidronate or zoledronic acid which act on new bone crystal called hydroxyapatite by blocking immature osteoclasts in the newly formed bone matrix.
Surgery is another option to treat Charcot foot, but there’s ongoing debate about whether it’s best to operate on the cart during the early or late stage. During the early stage, there are a lot of inflammation promoters like tumor necrosis factor-alpha, interleukin 1, and interleukin 6 that promote swelling and bone fragmentation. The main reason behind Charcot foot reconstruction surgery is to take the weight off the foot to stop ulcers and the worsening of deformities. A surgeon can reach this goal via several techniques including exostectomy, tenotomy, isolated, or multiple fusions with external and/or internal fixation. Surgeons tend to double the stabilizing hardware because the bone is softer, in order to prevent breakdown. There are also minimally invasive techniques that can be used depending on the surgeon’s experience.
Medical optimization includes giving up smoking, maintaining blood sugar levels under 7-8%, and recognizing micro or macro-vascular disease to decrease possible complications after the surgery.
What else can Charcot Neuropathic Osteoarthropathy be?
When diagnosing a condition known as Charcot, doctors often have to consider whether the patient might have a different condition with similar symptoms such as:
- Osteomyelitis (a bone infection)
- Cellulitis (a skin infection)
- Septic arthritis (a joint infection)
- Gout or pseudogout (types of arthritis caused by uric acid crystals)
- Foot/ankle sprain or fracture
- Deep vein thrombosis (a blood clot in the leg)
Unfortunately, Charcot is often misdiagnosed, with mistakes occurring about a quarter of the time. This can lead to around a 7-month delay in finding the correct diagnosis.
What to expect with Charcot Neuropathic Osteoarthropathy
Research has indicated that acute Charcot, a condition that affects the nerves and bones in the feet, generally takes about 8 months to go through all its stages. In a study, it was found that around 67% of patients with Charcot experienced additional problems, like developing ulcers on their feet. Furthermore, the study highlighted that patients who didn’t stick to their treatment plan had a significantly worse outcome.
Possible Complications When Diagnosed with Charcot Neuropathic Osteoarthropathy
Common foot deformities like flatfoot, rocker-bottom foot, hammertoes, and tight or stiff ankle are complications of certain conditions. These issues can cause bone bulges that might lead to potentially serious problems like ulcers, infection, or limb loss (amputation), and in severe cases, death. Additionally, cases of recurring Charcot’s joint, a condition characterized by the weakening of bones in the foot, are also frequent. Importantly, over a 5-year period, acute Charcot has a 13% mortality rate, similar to the rate of death observed in diabetics who don’t have Charcot’s joint.
Problems that might occur include:
- Flatfoot
- Rocker-bottom foot
- Hammertoes (bent toes)
- Tight or stiff ankle
- Bone bulges leading to ulcers or infection
- Limb loss
- Death
- Recurring Charcot’s joint
- 13% 5-year mortality rate from acute Charcot
Preventing Charcot Neuropathic Osteoarthropathy
Patients should have a clear understanding of the seriousness of their health situation and the potential life-changing complications that may come if they don’t strictly stick to their prescribed treatment plan. Charcot joint, a condition that causes the foot to become rigid and misshapen, could lead to multiple phased reconstructive surgeries.
In a different scenario, Charcot joint could result in what’s known as a ‘rocker-bottom’ deformity. This causes the foot to take on a shape similar to a rocking chair bottom. It can easily lead to a type of wound referred to as a neuropathic ulcer, with a bone infection beneath it, which may necessitate amputation of the affected limb. If a person has a ‘rocker-bottom’ foot, their risk of needing a major limb amputation increases massively, between 15 to 40 times.
If a diabetic patient requires a major amputation, their chances of survival over the next 5 years can be as low as 20%, with an upper limit around 70%. This survival rate is even less than that of patients who have breast or colon cancer. Therefore, prevention is crucial.
Simple daily measures for prevention include checking one’s own feet for any changes or issues, taking steps to ensure blood sugar levels are managed effectively, and making an active effort to avoid situations that could cause injury.
