Equinus is a condition in which the upward bending motion of the ankle is limited. Someone with equinus lacks the flexibility to bring the top of the foot toward the front of the leg. People with equinus develop ways to compensate for their limited ankle motion which often leads to other foot problems. The most common methods of compensation are flattening of the arch or picking up the heel early when walking, placing increased pressure on the ball of the foot.
There are several possible causes for the limited range of ankle motion. Often it is due to tightness in the Achilles tendon or calf muscles (soleus and/or gastrocnemius muscles). In some patients, this is an inherited trait. In other patients acquire the tightness through situations that keep the foot pointing downward for extended periods - such as being in a cast or frequently wearing high-heeled shoes. In addition, diabetes can affect the fibers of the Achilles tendon and cause tightness. Sometimes equinus is related to a bone blocking the ankle motion. Less often, it is caused by spasms in the calf muscle. These spasms may be signs of an underlying neurologic disorder, such as cerebral palsy.
Depending on how a patient compensates for the inability to bend the ankle properly, a variety of foot conditions can develop, including: plantar fasciitis, calf cramping, Achilles tendonitis, metatarsalgia, flat foot, arthritis of the midfoot, bunions, hammertoes, ankle pain, or shin splints.
Treatment options include strategies aimed at relieving the symptoms and conditions associated with equinus. In addition, the patient is treated for the equinus itself through one or more of the following options: calf-stretching exercises, night splints, heel lifts, or orthotic devices.