Diabetic Foot

Diabetes is a common condition affecting an increasing number of people in Australia and the developed world in general. It is usually managed by general practitioners and hormone specialists called endocrinologists, however some people will be referred to orthopaedic surgeons. For general information, see Diabetes.

Foot problems in diabetes are very common. They can take a number of forms including:

  • Skin problems – diabetics tend to have dry, brittle skin that cracks easily. This can lead to the formation of ulcers.
  • Infection – often occurs around an ulcer but can also occur as 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 mean 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 prevention of complications. When complications do occur, orthopaedic surgeons aim to help:

  • 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 a number of key 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 is damaged. In diabetics this can be due to (i) injury, (ii) blood vessel closure that limits the supply of blood and nutrients to the area of the skin, (iii) nerve problems. Ulcers can therefore have different appearances and may be painful or completely painless.
  • Osteomyelitis, or infection in the bone. Symptoms include vague aching pains in the foot that makes walking difficult. There may also be swelling. Sometimes, infected bone fractures with very little force causing a great deal of pain.
  • Difficulty healing after an injury. Infections and wound can take a very long time, even months to heal. They often require special treatment.

Causes

There are many underlying causes for the symptoms seen in a diabetic foot. This includes:

  • Infection – Diabetics are more prone to getting ulcers and infection in their feet. If infections are not taken seriously and treated adequately they can have severe consequences.
  • Nerve Problems – diabetics frequently have damaged nerves, especially in their feet. Most commonly the nerves affected are related to sensation or feeling, so that diabetics are more likely to injure themselves without realising and to lose their balance. In addition, people with long-standing diabetes may have damaged nerves to muscles. When muscles are not adequately stimulated by their nerves they start to shrivel and die. When this occurs in the muscles around a joint the unbalanced forces gradually pul the joint out of position, resulting in neuropathic (nerve-related) deformities. These may also be called neuropathic arthropathy, or nerve-related joint abnormality.
  • 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 increased ability to fight infection. In addition to supplying oxygen and nutrients, the blood contains white blood cells needed to fight infection. If a diabetics 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 bodies 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, or hyperglycaemia, especially those above 10, results in a much higher risk of developing complications in the future. If you are able to keep tight control on your blood sugars you greatly slow down the development of complications.
  • Poor control when diabetes first appears. Doctors are now realising that getting good control of your blood sugars in the first two years after being diagnosed is very helpful in reducing complications later on. Unfortunately, many people with type 2 diabetes have no symptoms, and are consequently unaware they have diabetes.
  • 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

There are a number of blood tests used to diagnose and monitor diabetes, however these will be performed by your GP and/or diabetes specialist.

Your surgeon may want:

  • X-Rays of your foot and ankle. The images will show bones that are misaligned and deformed. They may also show signs of infection in the bone, or osteomyelitis.
  • Angiogram. This tests the size and flow in the large blood vessels in your leg. Your surgeon may get you to have this test before surgery.
  • MRI / CT scan. These specialised imaging tests can show changes in the ligaments, muscles and tendon in your foot and ankle. They are also sometimes used to look for infection in the bone.

Complications

The changes in a diabetic foot can lead to their own complications. For example, deformity can lead to bony edges that rub against shoes and become ulcers.

Diabetics may gradually find they need more specialised shoes, have difficulty walking quickly or over uneven surfaces, and find they get tired more quickly.

Treatment

Treatment for a diabetic foot will vary depending on the complications present.

Treatment for Diabetic Deformity (‘Charcot Arthropathy’)

Initially, deformities in the foot will be treated by an orthoptist or podiatrist who can provide custom made shoes and teach you how to take care of the your feet and watch for developing injuries in the skin.

If your foot is red and swollen (‘Acute Charcot foot’) your doctors will give you pain relief and medication to help relieve the swelling, then wait for the inflammation to die down. During this time, you will be advised to keep your leg elevated as much as possible, and may need to wear 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 be used to realign bones, trim prominences away and occasionally to fuse joints together (‘arthrodesis’) – see Ankle Arthrodesis and Foot Arthrodesis.

Ulcers

Ulcers tend to heal very slowly in diabetics, especially when the ulcer is caused by rubbing of the skin against a shoe. When this is the 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 looking for signs of more serious complications (for example, osteomyelitis), then place a special dressing over the ulcer. This dressing will help to keep the ulcer sterile and promote the development of healthy tissue.
  • If the ulcer is severe enough, you may need to be non-weight-bearing or wear a cast to give the skin time to heal.

If all these treatments have failed to treat your ulcer and your doctors are concerned about infection, the surgeons may need to ‘debride’ or trim the damaged skin and tissue in your foot.

Cellulitis

This form of infection in the skin will require treatment with strong antibiotics and a stay in the hospital. Cellulitis usually does not require surgery, but if your doctors think there is an abscess, or collection of infected pus beneath the skin, you may need minor surgery to drain the abscess.

Treatment for Osteomyelitis

Infection in the bone is difficult to treat because the bacteria that cause the infection are often able to hide from antibiotics. For this reason, surgery is often required to remove the infected bone. Sometimes your surgeon will be able to remove part of the bone, but in other circumstances amputation may be required.

Seeking Advice

There are many health professionals involved in the treatment of diabetes and prevention of its complications. A good starting place is your family doctor.

There are a number of great websites with information on Diabetes, including:

Your Family Doctor (GP)

GPs see cases of diabetes almost every day, and will be able to both diagnose and discuss aspects of treatment with you. They will also be able to

  • Help you monitor your blood sugars
  • Prescribe medications
  • Refer you on to diabetes specialists, including diabetes educators, endocrinolgoists, 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 developing diabetes, including family members with diabetes, diabetes during pregnancy, or are overweight, you should see your GP for regular check-ups.

There are a number of simple blood tests that can be performed to see if you are at risk of developing diabetes soon.

Prevention

Prevention is the best way to cope with the complications of diabetes and can being even before you are diagnosed.

If you think you are at high risk of developing type 2 diabetes (for example, other people in your family have diabetes), there are a number of things you can do:

  • Diet and exercise. Maintaining a healthy body weight and keeping fit are excellent ways of improving your sensitivity to insulin and delaying the onset of diabetes.
  • See your GP regularly. If you or your GP is concerned about diabetes, you can do simple blood and/or urine tests. These will tell you if you have diabetes but also if you have 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 options to prevent the onset.

How do I prevent the complications of Diabetes?

  • Good control of blood sugar, especially in the early phase of diabetes.
  • Appropriate foot-care. The importance of careful and regular foot care in a diabetic patient cannot be stressed enough. This may include seeing a podiatrist. You should also wear appropriate footwear that is comfortable, soft but supportive.

Sometimes it is not possible to prevent complications like deformity from developing. Monitoring your feet regularly will however help you to notice when secondary complications are developing, for example and 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

More information on Diabetes and its complications can be found at:

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.