All You Need To Know About Diabetic Foot Ulcers
Diabetes refers to a condition of elevated blood sugar. A major health concern, diabetic foot problems are a common cause of hospitalization.
A majority of foot problems that diabetic patients face stem from two serious complications of the disease: nerve damage and poor circulation. Charcot arthropathy is one of the more critical foot problems these complications can cause. This condition can deform the shape of the foot and eventually lead to disability.
There are a number of treatment methods for various diabetic foot problems. However, prevention is the most effective treatment. For diabetic patients, it is essential to inspect the feet carefully every day to ensure overall health and prevention of damaging foot problems.
What are diabetic foot ulcers?
Nerve damage, also known as neuropathy, is a complication of diabetes that leads to a loss of sensation in the feet. Some diabetic patients are no longer able to feel when something has irritated or even punctured the skin. As such, even a wound as small as a blister can escalate into a serious infection in just a matter of days.
On top of that, diabetes also causes damage to the blood vessels, decreasing blood flow to the feet. Poor circulation weakens the bone, causing the bones and joints in the foot and ankle to disintegrate. Because of this, diabetic patients are at a high risk of breaking bones in the feet.
When a diabetic person fractures a bone in the foot, they may not even realise it because of nerve damage. As such, when they continue to walk on the injured foot, more severe fractures and joint dislocations can happen. Sharp edges of broken bone within the foot may point down towards the ground, increasing the risk of chronic foot sores from the abnormal pressure.
This can cause a condition known as Charcot arthropathy, which is one of the most serious foot problems that diabetic patients face. It is caused when the combination of bone disintegration and trauma warps and deforms the shape of the foot.
What are the symptoms of Charcot arthropathy?
Even though a patient who has Charcot arthropathy usually does not feel much pain, they may experience other symptoms.
- Warmth to the touch — the affected foot will feel warmer than the other.
- Swelling of the foot — this is the most sensitive sign of early Charcot foot and can occur without an obvious injury.
- Redness of the foot — this can also occur in the early stages.
- Swelling, redness, and changes to the bone that are seen on X-ray — this may be confused for a bone infection, although it is very unlikely to be one if the skin is intact and there is no ulcer present.
How are diabetic foot ulcers examined?
A physical examination and a look into the patient’s medical history
The patient will be asked about their general health and medical history, how the foot was injured as well as any symptoms they may have. Afterwards, the doctor will conduct a careful examination of the foot.
X-rays are imaging tests that provide detailed pictures of dense structures like bone. In the initial stages of Charcot, the X-rays may be normal. However, if the condition has progressed to the intermediate stages, the X-ray will show multiple fractures and dislocations of the joints.
Ultrasound and magnetic resonance imaging (MRI)
These studies are able to create better images of soft tissues in the foot and ankle. If the doctor suspects a bone infection, they may request for these scans to be done. Infection of the bone is extremely rare if there is no break in the skin.
A bone scan is a nuclear medicine test that is very effective in the determination of bone infections. As there are several different kinds of bone scans, the doctor will pick the best one to use based on the problem. An indium scan is a specialized test that involves placing a marker on white blood cells. These cells are then traced to learn whether they are travelling towards the bone to fight an infection. Both bone infection and Charcot foot will cause a positive positive bone scan (increased activity). However, only an infection will show a significant increase of activity on the indium scan.
How are diabetic foot ulcers treated?
In the treatment of Charcot arthropathy, the goal is to heal the broken bones and also prevent further joint destruction and deformity.
If the condition is still in the initial stages, a cast or cast boot is typically used to protect the foot and ankle. The use of a cast has proven to be very effective in protecting the bones and reducing swelling. When wearing a cast, the patient should not put any weight on the foot until the bones have started healing. It is usually also necessary to use crutches, a knee-walker device or a wheelchair. It can take 3 months or more for healing to take place. In order to ensure the cast continues to fit the leg as the swelling goes down, it will have to be changed every 1 to 2 weeks.
A specialized custom walking boot or diabetic shoe may be recommended after the initial swelling has decreased and the bones begin to fuse back together. This specialized shoe is designed to decrease the risk of ulcers, meaning sores that do not heal. Some diabetic patients may not be able to wear regular, over-the-counter shoes as they do not fit the deformed foot correctly.
If the foot deformity puts the patient at high risk of ulcers or if protective shoewear is deemed ineffective, the doctor may recommend surgery. Dislocations and unstable fractures would also require surgery to heal.
Mild deformity with tightness at the heel
In certain cases, the deformity is mild and associated with tightness at the back of the heel. If casting and protective shoewear do not yield any results after a period of time, ulcers in the front of the foot may be treated through Achilles tendon lengthening. In this procedure, the tendon that runs down the back of the leg and attaches to the back of the heel is surgically lengthened. This will decrease the pressure on the midfoot and front of the foot. As a result, the ulcer is allowed to heal and the chances of it returning are reduced.
Bony prominence on the bottom of the foot
A more severe deformity would be the appearance of a large bony bump on the bottom of the foot. If shoe modification fails to address this, surgery would be required. The kind of surgery would be determined by the stability of the bones and joints in the foot.
If the deformity is stable, surgery would only involve a simple removal of the prominent bone by shaving it off.
If the bones are too loose at the sight of the prominence, simply removing the bump will not be effective enough. This is because the loose bones will simply move and a new prominence will develop. In this situation, fusion and repositioning of the bones would be necessary.
Fractures that occur in the softer bone of diabetic patients are usually more complex. More hardware such as plates and screws are required during operation than for non-diabetic patients. These plates and screws may even be placed across normal joints to provide more stability.
This procedure is a highly challenging one and carries a greater risk of infections, wound complications and amputation as compared to normal foot and ankle fracture surgery.
There will normally be a period where no weight is allowed on the foot for at least 3 months after the operation. If one fails to follow these instructions and places weight on the foot too early, it can lead to complications such as the return or even worsening of the deformity.
It is hard to treat Charcot of the ankle simply with a brace or shoe. Usually, a surgical fusion of both the ankle and the subtalar, the joint below the ankle, is required to hold the foot straight. Given the amount of destruction of the bone and poor quality of soft tissue, there is a high risk of infection and the bone not healing. In such cases, amputation may be required as a first operation or to salvage a fusion that is infected or has not healed.
What can we conclude about diabetic foot ulcers?
In order to ensure the best possible outcome from treatment, it is crucial that one follows the doctor’s instructions on when it is safe to apply weight on the injured foot. Additionally, the sooner that Charcot arthropathy is diagnosed and treated, the better the final results. Patients should inspect both feet carefully every day and control their blood sugar levels. These are both essential in detecting Charcot foot early and avoiding even worse future complications.