Equinus

Equinus is a condition of the foot and ankle that refers to a tight Achilles tendon.  The Achilles tendon is composed of the tendons of two muscles – the gastrocnemius and the soleus.  Together, these two muscles form the strongest tendon in the entire body, which inserts into the calcaneus (heel bone). 

The Achilles tendon can become tight in one of several ways.  Spastic equinus is the oldest recognized form of equinus, and is seen as a result of upper motor neuron disease.  This may include cerebral palsy, stroke, or spinal trauma and disease.  Congenital equinus refers to equinus typically caused by a shortened Achilles tendon, which is present at birth.  This may result in prolonged toe walking in the developing pediatric patient. 

Most commonly, equinus is an acquired deformity, due to a tightness of the gastrocnemius muscle, the soleus, or both.  This tightness develops over time, and can be worsened by wearing high-heeled shoes, being casted for a lengthy period of time, or from overuse without stretching.  Bony equinus can also present, which is a block of both that prevents the ankle from dorsiflexing, or moving upwards. 

Equinus is possibly the most common cause of foot pathology.  When the Achilles tendon is tight, the body compensates for this in order to bring the heel to the ground.  This is often done by pronating at the subtalar joint, which is the joint located just below the ankle.  This extra pronation can lead to a number of foot problems, such as  plantar fasciitis, flatfoot, tendintis, arthritis, bunions, hammertoes, ankle pain, and a number of other conditions.  Thus, equinus is not necessarily a painful problem, but the compensation for it can cause several painful problems. 

Treatment of equinus should begin with an aggressive stretching program to address the tightness of the Achilles tendon.  Because of it’s relationship to the plantar fascia, the two structures forming a type of sling around the calcaneus, plantar fascia stretches are often incorporated as well.  Combined with the use of orthotics to maintain foot structure when walking, conservative treatment is often helpful for those with equinus.  Heel lifts may also be used to address some of the compensation for equinus at the subtalar joint, as it effectively lessens the amount of space that must be compensated for. 

Occassionally surgery may be necessary if the equinus is not relieved with conservative measures, and is causing significant foot pathology.  Surgery may involve lengthening of the Achilles tendon itself, or lengthening of either the gastrocnemius muscle, the soleus muscle, or both.  These procedures are often combined with foot procedures such as flatfoot or bunion correction, as they are often indicated as the deforming force in a foot deformity.  

Central Florida Foot & Ankle Center, LLC 
101 6th Street N.W. 
Winter Haven, FL 33881 
Phone: 863-299-4551 
www.FLFootandAnkle.com