Ruptured Achilles Tendon

The Achilles tendon is the largest and most vulnerable tendon in the body. It joins the gastrocnemius (calf) and the soleus muscles of the lower leg to the heel of the foot. The gastrocnemius muscle crosses the knee, the ankle, and the subtalar joints and can create stress and tension in the Achilles tendon. Tendons are strong, but not very flexible, so they can only stretch so far before they get inflamed and tear or rupture.

The exact cause of Achilles tendon ruptures is hard to say. It can happen suddenly, without warning, or following an Achilles tendonitis. It seems that weak calf muscles may contribute to problems. If the muscles are weak and become fatigued, they may tighten and shorten.

Overuse can also be a problem by leading to muscle fatigue. The more fatigued the calf muscles are, the shorter and tighter they will become. This tightness can increase the stress on the Achilles tendon and result in a rupture. This injury happens most often to "weekend warriors," according to the American College of Foot and Ankle Surgeons, middle-aged people who get their athletic activity in only on their days off.

Additionally, an imbalance of strength of the anterior lower leg muscles and the posterior lower leg muscles may also put an athlete at risk for an injury to the Achilles tendon.

An Achilles tendon rupture is more likely when the force on the tendon is greater than the strength of the tendon. If the foot is dorsiflexed while the lower leg moves forward and the calf muscles contract, a rupture may occur. Most ruptures happen during a forceful stretch of the tendon while the calf muscles contract.

Steroids and some antibiotics are also linked to Achilles tendon rupture. Many doctors avoid cortisone shots in or near the Achilles tendon due to this association.

A classic sign of an Achilles tendon rupture is the feeling of being hit in the Achilles area. There is often a "pop" sound. There may be little pain or a sudden pain in the area, but the person cannot lift up onto his toes while weight bearing, and walking uphill or upstairs is difficult. Swelling may appear on the back of the leg in the Achilles area.

You should seek immediate medical attention after the injury. The doctor will perform a physical examination and discuss what happened. That is usually enough to make the diagnosis, although sometimes an MRI may be ordered.

A completely ruptured Achilles tendon requires surgery and up to 12 weeks in a cast or walking boot. Surgery is preferred because it has a lower rate of re-rupture compared with non-surgical treatment. Partial tears are sometimes are treated with surgery following by a cast. 

Because the tendon shortens as it heals, a heel lift is used for six months, or more after the cast comes off. Physical therapy to regain flexibility and then strength is begun as soon as the cast is off.