Diabetes is a common condition that affects more and more people in Australia and in the developed world generally. It is usually managed by general practitioners and hormone specialists called endocrinologists, but some people are referred to orthopaedic surgeons. For general information, see Diabetes.
Foot problems in diabetes are very common. They can take several forms, including:
- Skin problems – people with diabetes tend to have dry, brittle skin that cracks easily. This can lead to ulcers.
- Infection – this often occurs around an ulcer, but it can also be an infection in the skin (cellulitis), the bone (osteomyelitis), or a general infection in your blood (sepsis).
- Deformity – the deformity of diabetes is also called ‘charcot arthropathy’, a medical term that means changes in the joints due to problems with nerves. Common foot deformities in diabetes include:
- bony prominences,
- claw toes,
- flatfoot.
- Complications after other injuries
The best approach to diabetes is preventing complications. When complications do occur, orthopaedic surgeons aim to:
- relieve your pain,
- improve your ability to walk without pain or instability
- prevent the formation of ulcers over prominent edges of bone
- remove infected skin, soft tissue and bone.
Symptoms
There are many possible symptoms in the diabetic foot.
- Deformity – deformity in the diabetic foot is the most common reason for referring a diabetic to an orthopaedic surgeon. There are several arthropathic deformities common in diabetes including:
- Flatfoot deformity – this occurs when the arch on the inside of the foot (instep) collapses.
- Bony prominences. This term refers to bones or edges of bones that stick out and rub against shoes, for example bunions. The skin over bony prominences is at risk of becoming damaged and ulcerated.
- Claw toe deformity is common among diabetics.
- Ulcers, skin infections etc – ulcers occur when the skin and its supporting tissue are damaged. In people with diabetes this can be due to (i) injury, (ii) blood vessels closing, which limits the supply of blood and nutrients to the skin, or (iii) nerve problems. Ulcers can therefore look different and may be painful or completely painless.
- Osteomyelitis, or infection in the bone. Symptoms include a vague aching pain in the foot that makes walking difficult. There may also be swelling. Sometimes infected bone breaks with very little force, causing a great deal of pain.
- Difficulty healing after an injury. Infections and wounds can take a very long time, even months, to heal. They often need special treatment.
Causes
There are many underlying causes for the symptoms seen in a diabetic foot. This includes:
- Infection – People with diabetes are more prone to ulcers and infection in their feet. If infections are not taken seriously and treated properly, they can have severe consequences.
- Nerve problems – People with diabetes often have damaged nerves, especially in their feet. Most commonly the nerves that carry sensation are affected, so people are more likely to injure themselves without realising and to lose their balance. In long-standing diabetes the nerves to muscles may also be damaged. When muscles are not stimulated properly by their nerves, they shrivel and die. When this happens in the muscles around a joint, the unbalanced forces gradually pull the joint out of position. This causes neuropathic (nerve-related) deformities, also called neuropathic arthropathy.
- Blood vessel problems (‘Vascular complications’) – the high blood sugar levels can be toxic to small blood vessels, causing them to close up. In the feet, this can cause ulcers to form as the skin becomes poorly supplied with oxygen and nutrients in blood.
- Vascular (blood vessel) complications of diabetes also result in a reduced ability to fight infection. In addition to supplying oxygen and nutrients, the blood contains white blood cells needed to fight infection. If a diabetic’s foot becomes infected and they have poor blood supply to that area, the infection is more likely to last longer.
Risk Factors
Risk factors for developing diabetes include:
- A family history of diabetes; this applies to both type 1 and type 2 diabetes.
- Diabetes during pregnancy, also called gestational diabetes.
- Metabolic syndrome:
- High fat content. Fat reduces the body’s sensitivity to insulin and consequently increases the risk of developing diabetes.
- Poly-cystic ovarian syndrome (PCOS). This is a common condition affecting many women. Women with PCOS have a higher risk of developing diabetes.
Risk factors for developing diabetic complications include:
- Poorly controlled blood sugars. Consistently high blood sugars (hyperglycaemia), especially above 10, greatly raise the risk of complications later. If you keep tight control of your blood sugars, you greatly slow the development of complications.
- Poor control when diabetes first appears. Doctors now realise that good control of blood sugars in the first two years after diagnosis is very helpful in reducing later complications. Unfortunately, many people with type 2 diabetes have no symptoms and do not know they have it.
- Insulin-dependent diabetics.
- Poor foot care. Many diabetics are referred to a podiatrist to help teach them how to (i) care for their feet and (ii) notice any developing problems. Podiatrists may suggest you avoid:
- Cutting your own toenails.
- Walking barefoot.
- Wearing poorly fitting shoes.
To minimise your risk of developing complications, try to wear soft, wide comfortable shoes with thick socks. If your feet do start to change shape, get new shoes.
Investigations
A number of blood tests are used to diagnose and monitor diabetes, but these are done by your GP and/or diabetes specialist.
Your surgeon may want:
- X-rays of your foot and ankle. The images show bones that are misaligned or deformed. They may also show signs of infection in the bone (osteomyelitis).
- Angiogram. This tests the size and flow of the large blood vessels in your leg. Your surgeon may ask you to have it before surgery.
- MRI / CT scan. These specialised imaging tests can show changes in the ligaments, muscles and tendons of your foot and ankle. They are also sometimes used to look for infection in the bone.
Complications
Changes in a diabetic foot can lead to further complications. For example, a deformity can create bony edges that rub on shoes and become ulcers.
People with diabetes may gradually find they need more specialised shoes, have trouble walking quickly or on uneven surfaces, and tire more quickly.
Treatment
Treatment for a diabetic foot will vary depending on the complications present.
Treatment for Diabetic Deformity (‘Charcot Arthropathy’)
At first, foot deformities are treated by an orthotist or podiatrist, who can provide custom made shoes and teach you how to look after your feet and watch for skin injuries.
If your foot is red and swollen (‘acute Charcot foot’), your doctors will give you pain relief and medicine to reduce the swelling, then wait for the inflammation to settle. During this time you will be advised to keep your leg raised as much as possible, and you may need a cast to keep your ankle still.
Surgery to correct deformities will only be considered if:
- Your leg is NOT swollen or in any other way inflamed or infected
- You have adequate blood vessels in your leg
Surgery can realign bones, trim prominences away and occasionally fuse joints together (‘arthrodesis’) – see Ankle Arthrodesis and Foot Arthrodesis.
Ulcers
Ulcers tend to heal very slowly in people with diabetes, especially when they are caused by the skin rubbing on a shoe. In this case a podiatrist or orthotist may recommend:
- Shoe modifications and shoe inserts to relieve the pressure on the area of skin
- Skin dressings. Your podiatrist will often clean the ulcer and look for signs of more serious problems (for example osteomyelitis), then place a special dressing over it. The dressing keeps the ulcer sterile and helps healthy tissue grow.
- If the ulcer is severe, you may need to stay off the foot or wear a cast to give the skin time to heal.
If these treatments fail and your doctors are worried about infection, the surgeons may need to ‘debride’ (trim) the damaged skin and tissue in your foot.
Cellulitis
Cellulitis is an infection in the skin. It needs strong antibiotics and a stay in hospital. It usually does not need surgery, but if your doctors think there is an abscess (a collection of infected pus under the skin), you may need minor surgery to drain it.
Treatment for Osteomyelitis
Infection in the bone is hard to treat because the bacteria that cause it can often hide from antibiotics. So surgery is often needed to remove the infected bone. Sometimes your surgeon can remove part of the bone, but in other cases amputation may be needed.
Seeking Advice
Many health professionals are involved in treating diabetes and preventing its complications. A good place to start is your family doctor.
There are a number of great websites with information on Diabetes, including:
- Diabetes Australia – this site also has a section dedicated to Diabetes and Feet.
- Australasian Podiatry Council – this site has a number of pamphlets, including information on Diabetes and footcare.
- Australian Diabetes Educators Association
- The Indigenous Diabetic Foot Program
Your Family Doctor (GP)
GPs see diabetes almost every day and can diagnose it and discuss treatment with you. They can also:
- Help you monitor your blood sugars
- Prescribe medications
- Refer you on to diabetes specialists, including diabetes educators, endocrinologists, podiatrists and many others.
Your GP can also give you advice on how to delay the onset of diabetes and prevent complications.
When should I see my GP?
If you have a number of risk factors for diabetes, such as family members with diabetes, diabetes during pregnancy or being overweight, see your GP for regular check-ups.
Simple blood tests can show whether you are at risk of developing diabetes soon.
Prevention
Prevention is the best way to cope with the complications of diabetes and can begin even before you are diagnosed.
If you think you are at high risk of type 2 diabetes (for example other people in your family have it), there are things you can do:
- Diet and exercise. Keeping a healthy weight and staying fit are excellent ways to improve your sensitivity to insulin and delay the onset of diabetes.
- See your GP regularly. If you or your GP is worried about diabetes, simple blood and/or urine tests can show whether you have diabetes, or a condition called ‘pre-diabetes’. This simply means you are borderline and may develop diabetes in the future. Your GP can then talk to you about ways to prevent it.
How do I prevent the complications of Diabetes?
- Good control of blood sugar, especially in the early phase of diabetes.
- Appropriate foot care. Careful, regular foot care is very important for people with diabetes. This may include seeing a podiatrist. You should also wear comfortable, soft but supportive footwear.
Sometimes complications like deformity cannot be prevented. Checking your feet regularly will help you notice when other problems are developing, for example an ulcer over a prominent toe.
Ulcers in diabetic feet are serious and can lead to osteomyelitis (infection in the bone)!
F.A.Q. | Frequently Asked Questions
Why can I have a foot ulcer and not feel it?
Diabetes can damage the nerves that carry feeling, especially in the feet. Cuts, blisters and ulcers can then be completely painless, so they can go unnoticed and get worse. This is why checking your feet every day matters.
When is a foot problem an emergency?
See a doctor the same day if you have a new ulcer, a wound that is not healing, or spreading redness, swelling, warmth or pus. Go to the emergency department if you also have a fever or feel unwell, or if the foot turns black, white or cold. Infection in a diabetic foot can spread quickly.
Can a Charcot foot be treated without surgery?
Yes. Treatment starts with taking weight off the foot, usually in a cast or boot, and keeping the leg raised until the redness and swelling settle. Surgery is only considered later, when the foot is no longer inflamed, if the deformity is causing ulcers or cannot be managed with special shoes.
How can I protect my feet every day?
Look at the tops, soles and between your toes each day, using a mirror or asking someone to help. Wash and dry your feet well, especially between the toes. Never walk barefoot, wear soft, wide shoes that fit well, and see a podiatrist regularly. Tell your doctor straight away about any change in the shape or colour of your foot.
More information on Diabetes and its complications can be found at:
- International Diabetes Federation
- Diabetes Australia
- Australian Diabetes Educators Association
- The Indigenous Diabetic Foot Program
References
Laughlin, R. T., et al., ‘The Diabetic Foot’, Journal of the American Academy of Orthopaedic Surgeons, Vol. 3, No. 4, July/August, 1995, pp 218–225.
Skinner, H. B. (Ed), ‘CURRENT Diagnosis and Treatment in Orthopedics’, 2nd Ed., Lange Medical Books, USA, 2000.