Definition
Charcot deformity was originally associated with neurogenic infections such as tertiary syfilis. Today it is mainly seen as a complication or late manifestation of a diabetic patient with neuropathia or in other situations where sensation is grossly disturbed. The definition is that the foot is collapses in a segment structurally with disruption of normal alignment and balance leading to protrusion of bone and non-physiological pressure points with development of ulcers, sores and difficulties in accomodation of shoe-wear. Charcot foot development is thought to become a major problem in future health care as Diabetic incidence is increasing in the whole world.
Causes
The cause of Charcot foot is debated. The mechanical theory suggests that the insensate foot allows for repetitive overuse and associated microtrauma, leading to multiple stress fractures and the development of the Charcot ligamentous and bony deformities. The neurovascular theory suggests that a loss of regulation in blood flow to the injured site allows for increased bone resorption, whereas a third theory suggests a loss of balance
between bone resorption and bone formation at the level of the osteoclasts and osteoblasts (different cell-types in bony structure). It has been shown that often the first part to fail are the soft tissues such as the plantar fascia, leading to secondary alleviated stress on the bone-joint-structure.
Symtoms
It is very important to recognize the early symtoms as the outcome otherwise might be fatal or more complicated.
Often without any clear distorsion or with a history of a minor sprain, the patient presents with a red,swollen, warm foot. If no wounds are present and the patient has poor sensation even to touch the early development of charcot foot or neuroosteoarthropathy must be supected. The main differential diagnosis is an septic infection, which needs to be outruled.
If untreated the swelling will continue and if the patient continues with unprotected weight-bearing the structure of the foot inevitably will deteriorate and collapse on the ground.
Depending on which segments of the foot are affected the problem is different. Typically a heel-charcot might lead to an ulcer with infection wheras a problem developing in the ankle could lead to a totally unstable foot that will be disconnected from the lower leg and impossible to fit in shoes. Further down the foot the deformity will lead to grand deformity with bone protruding to the sole and widening of the foot and possible ulcers etc. If consolidated a rocker- bottom deformity might be the end-stage.
On the whole this situation is to be thought of as un unstable fracture- dislocation in someone who cannot feel pain and thus will not care to protect the structure.
Diagnosis
The clinical exam together with the patient’s history should make the clinician suspicious of this condition. If infection cannot be outruled a combined tretament with antibiotics and stabilisation should be considered. Usually blood-tests , inflammatory responses and radiology sometimes with MRI is considered
Medical treatment
The primary treatment is to remove the deforming stress and protect the structure with stabilising measures.
Typically this should be done with a contact cast or an orthosis that lowers the deforming forces, Often non- weight bearing with crutches or knee-walkers or even wheel-chair is necessary.
After some time, often months the swelling diminishes and if protected the foot will have kept it’s shape and structure. However a deformity often will develop and in this later cold face when the warmth and swelling has subsided the patient is let weight- bearing with accomodated shoe-wear and orthotics.
Surgical treatment
If the patient can ambulate with some means and is stable enough not to develop progressive deformity with ulcers or possible pain surgery is not necessary. However function is often poor after these conditions and if there are continuous problems surgery might be necessary.
These problems usually need major reconstructions and major resources to improve.
Major resections of joints with stabilising fusions have been reported to favorably improve the outcome when skilfully performed. The risks of infection are obvious but the risks of no tretament often are the same and the goal is to avoid amputation and make the use of accomodated shoewear for ambulation and walking possible.
Normal or restored function cannot be expected, the charcot foot will always lead to some dysfunction in the aftermath.