• The disease
• Diagnosis
• Treatment options

Definition

Equinus (from the Latin “equus” for horse) is a downward flexion deformity of the foot. With this condition, toe walking replaces the normal walking pattern.

There are several possible causes:

• uncontrolled contraction (spasticity) of the calf muscles following brain injury, which can cause insufficient dorsiflexion (the upward bending motion of the foot towards the tibia) of the foot and toes;
• a deformity of one foot, or often both feet, in the uterus. It is the cause of a congenital dysplasia (a development anomaly leading to a malformation or deformation) of all the tissue under the knee (bone, ligaments, nerves and blood vessels).

Symptoms and impact on health

The severity of equinus deformation varies. It is termed ‘dynamic’ when it is still possible to stretch the calf muscles. When fibrosis (the formation of excess fiber after significant amount of tissue is destroyed) prevents stretching the calf muscle, the condition is known as static equinus deformity.

The abnormal gait (on the front of the foot) caused by equinus affects the patient’s mobility and balance and puts excess pressure on the ankle. The resulting claudication – or limp – also has a negative effect on patients’ mental well-being and social life.

Etiologies

The chief causes of equinus deformity are cerebral stroke (CAV) in adults, which is the main cause of the disability in France, and cerebral palsy in children. A cardiovascular accident can leave patients with spasticity of the upper limbs, which in turn leads to equinism.

Where equinus is a birth deformity, the pathology is either idiopathic (a non-hereditary disease of unknown cause), caused by a neuromuscular disorder, or related to other malformations.

Incidence

Worldwide, more than 100,000 children are born with equinus deformity. In France, the incidence is 1 to 2 cases per 1,000 births. Boys make up the majority at 70% of cases. We do not have sufficient available data to reliably estimate the frequency of equinus of diverse origin (cerebral palsy, cerebral stroke (CAV), multiple sclerosis (MS), head trauma, etc.) in patients aged two or over.