Ankle algodystrophy

What is ankle algodystrophy?

Ankle algodystrophy is a rare but classic complication; it is a painful reaction that is disproportionate to the initial trauma.

It is an inflammatory reaction that exceeds the body's regulatory capacities.

This diagnosis is too often made in the case of a chronically painful ankle.

Any ankle algodystrophy is a mechanical or infectious problem until proven otherwise, as algodystrophy is a diagnosis of exclusion.

It generally progresses in 2 phases: a hot phase known as the inflammatory phase and a cold phase known as the pseudo-inflammatory phase. The duration of algodystrophy can range from several weeks to several years.

Algodystrophy affects both women and men, regardless of age.

The symptoms of ankle algodystrophy

There are several symptoms of ankle algodystrophy:

• pain
• vascular disorders
• trophic disorders
• neurological disorders

Pain

During the hot phase, pain caused by the trauma increases; it is of mixed mechanical and inflammatory type. The pain is very intense, diffuse, poorly localized, and permanent.

Ankle pain increases with weight-bearing and with movement of the ankle; there is morning stiffness with a feeling of loosening up when weight-bearing resumes.

Palpation of neighboring joints, such as the foot and knee, can be abnormally very painful; this is called allodynia.

During the cold phase, allodynia persists but is less severe. The intensity of pain while walking and moving the ankle remains very high.

During the recovery phase, the pain is more likely due to the aftereffects of the two previous phases—that is, to joint stiffness and the retraction of tissues such as joint capsules and tendons.

Vascular disorders

During the hot phase, there is a massive release of inflammatory substances that causes dilation of the small blood vessels and increased permeability of the veins.

The ankle is generally swollen (swelling), the skin is red and warm, sometimes displaying a purplish hue when standing.

There is then a swelling of the lower limb that can reach up to the knee.

During the cold phase, the ankle becomes less swollen, the swelling gradually subsides, the skin becomes rather thin, cyanotic or bluish, with hair loss.

Trophic disorders

These are present during the cold phase, with hair loss or, on the contrary, hypertrichosis; the skin is thin and stiff, with possible nail lesions.

Neurological disorders

There is cutaneous hyperesthesia, meaning increased pain sensitivity, and allodynia, which is an abnormal painful sensation.

Increased sweating (hyperhidrosis) may be noted, along with muscle weakness of the lower limb, tremors, and dystonic phenomena related to motor impairment.

What are the causes of ankle algodystrophy?

There are several causes of ankle algodystrophy.

Trauma

Algodystrophy is most often post-traumatic. It is not the severity of the trauma, but the post-traumatic pain that can promote algodystrophy.

Pain management is crucial in emergencies, and initially requires immobilization of ankle fractures.

A cast that is too tight can cause significant pain, or even compartment syndrome, and be responsible for the onset of algodystrophy. Monitoring a patient in a cast is essential both preoperatively and postoperatively.

An ankle surgery can cause algodystrophy, but it is necessary to look for a mechanical cause of pain such as a cast that is too tight, persistent bone or ligament injuries after a first procedure.

Bone diseases

Osteoporosis, which is a bone fragility, can lead to algodystrophy in the case of a stress fracture.

Lobstein disease, also known as brittle bone disease, can be responsible for fractures due to a lack of bone elasticity which can cause algodystrophy.

Psychological factors

Anxious and depressive personalities are more at risk of developing algodystrophy.

Diagnosis of ankle algodystrophy

The diagnosis of ankle algodystrophy is clinical, but it is a diagnosis of exclusion. This diagnosis should not be made excessively, so as not to miss a fracture, ligament instability (especially the syndesmosis) a joint infection, or even an ankle cyst that requires urgent medical-surgical intervention.

Biological and imaging tests help rule out differential diagnoses.

Biological assessment

It does not show any inflammation.

Joint aspiration does not reveal any germs; it shows mechanical fluid.

Radiological assessment

There are characteristic signs on X-ray that appear after 2 months of progression.

Radiolucency corresponds to a diffuse bone demineralization with a speckled or mottled appearance of the bone on both sides of the ankle.

The bone framework may be less dense with mechanical strength decreasing by 40%.

MRI

MRI allows for earlier diagnosis than X-ray, as signs of bone edema and hyperemia appear after 1 month of progression.

Scintigraphy

Scintigraphy shows early and diffuse hyperfixation around the joint. This hyperfixation can persist for months after symptom resolution.

What are the treatments for ankle algodystrophy?

Medical treatment

Treatment is primarily preventive. Pain management is essential.

The administration of vitamin C may have a preventive role in patients with a fracture.

Physical therapy

Physical therapy is essential throughout the entire progression of complex regional pain syndrome. It helps to limit joint stiffness and maintain some degree of muscle trophicity.

Balneotherapy using Scottish baths, alternating hot and cold, may be effective.

Surgical treatment of complex regional pain syndrome of the ankle

Surgical treatment is indicated at two stages of the progression of complex regional pain syndrome: in cases of after-effects during the recovery phase, and in cases of factors maintaining the condition.

During the sequelae phase, there may be tissue contractures and stiffness in the ankle and foot joints. Surgical procedures can therefore be considered to restore a flat foot position in case of abnormal posture. Achilles tendon lengthening is a classic procedure in cases of equinus position.

If an ankle fracture is untreated or insufficiently treated, we may have to operate on a patient to stabilize the ankle, or reoperate to complete the stabilization in the hope of then limiting the duration of complex regional pain syndrome.

Psychological support

Since the progression can be very long, psychological support is necessary.