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August 2014

Heel pain may be caused by a tight or contracted Achilles tendon.

Achilles heel iStock_000047636266_Large (2)
Tight or contracted Achilles tendon can lead to plantar fasciitis or heel pain.

The ankle joint allows the foot to move up and down (dorsiflexion and plantarflexion). The foot needs to be able to move up on the leg by about 15 degrees in order to allow normal gait. Upward motion of the foot on the leg is called dorsiflexion.

Lack of adequate dorsiflexion range of motion is called functional equinus. The term “equinus” is derived from the Latin “equus” for horse. A horses hoof points downward without upward motion.

What causes functional equinus?

      1. Congenital causes: The Achilles tendon and muscles that make up the Achilles tendon in the leg may be contracted due to position of the baby in the womb.

      2. Biomechanical causes: The Achilles tendon is created by two large muscles in the back of the leg, the Gastrocnemius and Soleus muscles. Those muscles often overpower the smaller muscles in the front of the leg leading to an imbalance.

      3. Neurologic causes: Any neurologic condition causing weakness in the anterior muscles group (muscles in front of the leg) can lead to overpowering of the posterior muscle group (the muscles making up the Achilles tendon) allowing the posterior muscles to pull the foot into equinus.

      4. Poor shoegear choices: Long term use of high heels can cause shortening of the Achilles tendon. Additionally, use of poorly supportive shoegear may lead to compensatory tightening of the posterior muscle group.

      5. Bony causes: Bone spurs in front of the ankle or ankle joint deformity caused by fractures can reduce dorsiflexion at the ankle.

      6. Iatrogenic causes: “Iatrogenic” means that the condition is caused by medical care. For example excessive tightening of the Achilles tendon after surgical repair, ecessive scar tissue or poor positioning during casting can lead to functional equinus.

The Achilles tendon attaches to the back of the heel bone and the plantar fascia attaches to the bottom of the heel bone. A tight Achilles causes tightening of the plantar fascia. Additionally, if the foot cannot adequately dorsiflex (move upward) on the leg as one pushes off, then one must compensate, finding a different way to achieve that motion.

The joint beneath the ankle joint is the subtalar joint. The subtalar joint is responsible for side to side motion, inversion (turning in) and eversion (turning out). The motion at the subtalar joint is not pure eversion/inversion but when one turns the foot out, it also moves up (dorsiflexes) a bit. That motion is known as “pronation.” The opposite motion is known as “supination” which is a combination of inversion and pointing down (plantarflexion). If there is functional equinus then the foot will compensate by overpronating during push off (propulsion). Pronation in that manner will lead to a twist of the middle of the foot with each step and a twisting of the fascia. Chronic repetitive twisting of the fascia causes it to become thickened and painful. A rigid shank in the shoe can signficantly reduce the problematic twisting or torsion of the fascia.

Patients with functional equinus often tolerate orthotics poorly or obtain inadequate relief from orthotics because such devices attempt to block the compensatory motion needed for the patient to push off. It is necessary to treat the functional equinus before the orthotic can work.

Treatment of functional equinus.

  1. Manual therapy. This refers to the type of physical therapy in which the practitioner manual works to elongate the Achilles. The Achilles does not truly elongate but such elongation occurs in the region immediately above the Achilles known as the Gastrocnemius aponeurosis. The Gastrocnemius aponeurosis is a flat membrane below the Gastrocnemius muscle belly (the muscle that forms the back of the calf).

  2. Night splints. These are devices that look like boots, oftern worn at night, which gradually lead to elongation of the contracted Gastrosoleus-Achilles complex, restoring dorsiflexion range of motion. It is very important that these be adjusted properly and patients be provided with adequate instruction on their use. We see a large number of patients who have obtained such devices and attempts to use such devices without such information.

  3. Surgical treatment. Achilles tendon lengthening. This is rarely needed for mild to moderate contracture of the Achilles but is indicated for more severe degrees of contracture or, at times, when there is a neuromuscular issue that need be addressed.

 

Dr. Ed Davis  Podiatrist San Antonio  210-490-3668   http://www.southtexaspodiatrist.com/