CNS: Charcot Foot In Diabetes: An Enigma

Charcot neuropathic osteo-arthropathy, commonly referred to as the Charcot Foot, is a condition affecting the bones, joints, and soft tissues of the foot and ankle. The disorder was first brought to the world’s attention in 1983 by Dr Jean Martin Charcot when he referred to the disease process as a complication of syphilis in the knee joint in his patient. Syphilis was believed to be the most common cause of Charcot arthropathy until 1936, when Dr William Jordan linked it to diabetes. Diabetes is now one of the leading causes of Charcot Foot especially in patients with a long history of the disease. In India the incidence is 1%, but detection rates are increasing, perhaps due more awareness.

The clinical challenges in the diagnosis and management of the Charcot Foot in diabetes were discussed at length at the Amrita Endocrinology, Diabetes and Diabetic Foot Conference (AEDFC 2012) held recently at the Amrita Institute of Medical Sciences, Kochi. Several world renowned surgeons gave their valuable insights on the subject, separating facts from fantasy.

The diabetic Charcot foot syndrome is a serious and potentially limb-threatening lower-extremity complication of diabetes. Dr Aparajita Nakhra, a specialist in Reconstructive Foot and Ankle Medicine and Surgery from Arizona, describes it as, 'A degenerative, irreversible disease involving progressive non infectious destruction of one or multiple bones and/or one or multiple joints associated with long term neuropathy due to diabetes or substance abuse of alcohol, or leprosy or any other neuropathic condition.'

As per the modern theory peripheral neuropathy (sensory/motor or autonomic) leads to Charcot Foot conditions. A normal person has the gift of pain, in order to rest when there is injury, which a neuropathic person does not have. And so the system is traumatized simply by continuing to walking on a dislocation fracture. Sensory neuropathy essentially affects the small nerve fibres. Motor neuropathy involves the large or long nerve fibres. Autonomic neuropathy is the dysfunction of the sweat glands—there is breaking of the skin which allows bacteria to enter which becomes a source of infection.

This condition can affect any upper or lower limb joint (forefront, mid tarsal, ankle joint) but the hallmark deformity associated with this condition is mid foot (or Lisfranc joint) collapse, described as a ‘rocker-bottom’ foot. The radiographic hall marks are bone destruction, fragmentation, bony remodeling and joint destruction. Dr Robert Frykberg, Chief of Podiatry Section at Carl T Hayden VA Medical Centre, USA, calls it the, ‘most humbling of all deformities and a difficult and challenging diagnostic dilemma.’

There are 4 stages in the natural history of Charcot Foot:-

Stage zero is the clinical stage—the injury has already occurred but the patient may or may not recall injury because of the underlying neuropathy. There is swelling and local warmth and acute signs of inflammation. However there is no radiographic evidence and X rays are negative. The treatment consists of limited weight bearing with Total Contact Cast (TCC) or prefabricated pneumatic walking braces (PPWB). Dr Frykberg cautions that, “If the disease is not picked up at this stage the patient continues to walk and progresses to the next Stage 1 of debris formation. So the goal is to diagnose in stage zero when no bone destruction has taken place and to calm down the inflammatory response to prevent progression to other stages. The preservation of protecting musculature by physical therapy still holds good. We immobilize these patients and I am very much in favour of TCC to reduce the inflammation. Conservative treatment is recommended which maybe frustrating, never entirely satisfying, but frequently rewarding.”

However, according to Dr Aparajita Nakhra, “I am not a TCC person as from cost point of view it is difficult to justify one. Also published medical evidence says that similar good results are obtained with custom made footwear/diabetic shoes or casting. Patients should be kept strictly non weight bearing for at least 3 to 4 weeks. Once the edema is resolved they can be given a walking cast. The take home point for this stage is to treat it aggressively by making the patient non weight bearing.”

Stage one is the fragmentation stage with debris formation. There could be fractures, joint dislocations and aggressive edema. Treatment consists of limited weight bearing with TCC.

Stages zero and one are called the acute stages. Surgery is generally not recommended in the acute inflammatory stages because of the perceived risk of wound infection or mechanical failure of fixation. But destruction of the bone has to be arrested.

Stage two is coalescence (sclerosis) of bone. This is the quiescent stage with re-absorption of bone debris. Inflammation and edema is reduced. There is chronic early deformity, and there is high risk of developing ulceration. As Dr Nakhra rightly believes, “The goal now is to prevent progression to stage three. We want to prevent severe rock bottom deformity; we want to prevent ulceration as it is the precursor to infection. These patients should be kept mobile and be able to walk to keep their sugar and their heart problem under control.”

Stage three is reparative stage when the foot is stable. There is the final resolution of redness and swelling. There may be a rock bottom deformity. This is the stage when one takes chronic Charcot foot reconstruction. The risk of ulceration is much greater now.

Treatment for stages 2 and 3 is protective weight bearing (TCC followed by Charcot restraint orthotic walker --CROW) or a possible surgical intervention for removal of bony prominences associated with ulceration.

Dr Nakhra says that, “The potential outcomes we can end up with in these 3 stages could be (i) a normal foot if one is lucky and the patient is compliant, but this nearly never happens; (ii) a stable foot with some deformity that can be accommodated via custom bracing or foot wear; (iii) a stable foot with some deformity that cannot be accommodated; (iv) a complete loose bag of bones with a very unstable foot. Treatment is custom bracing/ shoes and custom inserts that need to be closely monitored. The key is to watch these patients so that they do not end up with any ulceration. In case of non accommodating stable foot, if the patient does not respond to conservative treatment like custom bracing then surgery is very likely. In case of an unstable foot or ‘a loose bag of bones’ there has to be reconstructive surgery—be it internal or external fixation.”

The treatment goals for Charcot Foot should be to prevent further deformity; provide protected ambulation; and prevent recurrent ulcers and instability. To move from active to non active stage it is recommended for the patient to be non weight bearing, take bed rest, be on wheel chair. Total Contact Cast (TCC) is very acceptable. Offloading and immobilization with the help of ace bandage, Jones dressing, TCC, CROW brace is a must. Acute dislocations without bone fragmentation may be treated with early fusion. Surgery is generally advised only in case of infected bone (osteomyelitis), removing bony prominences and/or correcting deformities that could not be successfully accommodated with therapeutic footwear, custom ankle-foot orthoses, or a CROW.

According to Dr Frykberg, “Conservative treatment is always best. Non ulcerating Charcot foot treatment is generally based on therapeutic footwear to provide protective ambulation to prevent ulceration. Sometimes bracing is required as well, especially for the unstable Charcot foot. In case of ulcerating chronic Charcot feet, we have to treat with proper off loading techniques and TCC or non removable walking braces to heal the ulceration. Achilles tendon lengthening can also help at times. If ulceration continues to recur then we have to consider surgical intervention which may be a better alternative to amputation. However, Charcot foot surgery is replete with complications. It requires long periods of non weight bearing, during which time other complications may develop. We are talking of may be as long as 12 months of keeping these people off their feet. Total immobility has disadvantages like loss of muscle tone, reduction in bone density, and loss of body fitness. Sometimes we may have to take difficult decisions and make smart choices between amputation and salvaging the limb. So our goal should be to convert the ulcerating Charcot foot to the non ulcerating one. We can use a variety of fixation techniques called super constructs to maintain realignment.”

Dr Nakhra cautions that, “Charcot Foot requires careful initial and long term follow up. The patient and the family should be kept involved in the treatment process so that they can better appreciate what the challenges are, and understand that the end result may not always be up to everyone’s hope and satisfaction.”

In an interview given to Citizen News Service (CNS), Dr Frykberg sums up the problem of Charcot Foot succinctly: ‘It is early diagnosis, early offloading, catching it early which minimizes the problems associated with it. If we wait, if it is left undiagnosed and patient keeps walking, then it is very limb threatening as ulcers get infection. So everything is dependent upon high degree of clinical suspicion, early diagnosis and early offloading.”

Shobha Shukla - CNS

(The author is the Managing Editor of Citizen News Service (CNS). She is a J2J Fellow of National Press Foundation (NPF) USA. She received her editing training in Singapore, has worked earlier with State Planning Institute, UP and taught physics at India's prestigious Loreto Convent. She also authored a book on childhood TB (2012), co-authored a book (translated in three languages) "Voices from the field on childhood pneumonia" and a report on Hepatitis C and HIV treatment access issues in 2011. Email: shobha@citizen-news.org, website: http://www.citizen-news.org)