Plantaris Tendon Rupture Symptoms: Its Diagnosis And Treatment

Plantaris muscle is a thin muscle located on the back of lower leg. It is one of the calf muscles which lie below the gastrocnemius and soleus muscle. The belly of plantaris muscle is small while its tendon is long like a thin rope which attaches to the medial side of heel bone called the calcaneus. Due to its thin size as compared to other large muscles the whole muscle is often mistaken as a tendon or a large nerve.

Rupture of plantaris tendon is associated with pain, swelling and hearing of a pop sound in the back of lower leg.

Injury to plantaris tendon is common in certain activities which require quick movement of foot in specific direction. Activities such as jumping, running, or pushing the leg forcefully may lead to tear of plantaris tendon fiber.

It is common in people who play certain sports such as tennis and soccer. Often the condition is therefore called tennis leg. Although it may take some time for complete recovery, the mode of treatment is conservative in majority of cases.

Symptoms Of Ruptured Plantaris Tendon

The function of plantaris muscle is not clearly understood and the muscle is considered to be of lesser importance to the body.

However, many people believe it is involved in flexon of foot and knee together with other dominant muscles. Usually the rupture of plantaris tendon occurs near the tendo Achilles junction.

In most cases a small portion of gastrocnemius muscle is also injured. The rupture occurs during activity which requires movement of foot. The clinical features of plantaris rupture are;

  • Patient hears a pop sound at the back of lower leg when the tendon is torn.
  • Soon after the rupture patient experiences pain and swelling at the site of injury. It is mainly near the junction of Achilles tendon. The area becomes sore.
  • Pain can become severe when the patient takes rest few hours later. The intensity of pain increases from flexion of ankle and foot.
  • The swelling may increase from ankle to the foot. There may be visible ecchymosis.
  • Plantaris injury does not disturb nerve function. It remains intact.

Plantaris Tendon Rupture Diagnosis

Since the plantaris and Achilles tendon attach on the same side of heel bone, sometimes it becomes difficult to distinguish whether the injury is to Achilles tendon or the plantaris tendon. It is necessary to rule out rupture of Achilles.

If the patient is able to walk or stand for few seconds on toe, it rules out Achilles tendon injury. Patient is unable to flex his foot when he has Achilles rupture.

Besides physical tests, imaging techniques such as ultrasound and MRI can help to confirm the diagnosis of rupture of plantaris tendon.

Treatment For Plantaris Tendon Rupture

Once Achilles tendon rupture is ruled out, and the condition is confirmed to be plantaris tendon rupture, in majority of cases the treatment is conservative. It takes almost 4 to 12 weeks for complete recovery.

Management is focused on reducing pain and swelling.

  • Painkillers and anti-inflammatory medications are useful in reducing pain and swelling.
  • Patient has to rest for few days or week or walk with the help of crutches to prevent weight bearing on the affected leg.
  • Soon after the injury, compression with ice is beneficial in reducing pain and swelling. Take few cubes of ice and wrap it in a clean cloth. Place the cloth on the injured area.
  • Elastocrepe bandage is applied from foot to the knee to keep the foot and ankle stable.
  • After few days gentle massage and physical therapy will help to strengthen the tendon.

During the healing period patient should avoid all outdoor sports activities and allow the injury to recover earlier.