The plantaris is a very thin/short muscle located behind the knee joint with a tendon approximately 2-4 inches long.
Until recently the muscle was considered to be relatively insignificant, mainly assisting calf muscle in bending the knee and pointing the the foot down at the ankle.
The plantaris muscle starts just above the outside section of the calf muscle and runs medially down the back of the leg until it insert into the Achilles Tendon or sometimes inserting separately on the inside of the calcaneus (heel bone).
This tendon is often neglected in clinical diagnosis of midportion calf pain. However recently there has been more research and clinical studies to show that the plantaris tendon is responsible in some cases of midportion calf pain.
This occurs when the tendon is located very closely or invaginated into the Achilles tendon. The plantaris tendon is thicker in patients with chronic painful midportion calf pain.
This condition may be the reason why some people do not respond to detailed load programs and never rehabilitate properly or have recurrent flare ups of symptoms of Achilles and calf pain.
Causes of Invaginated Plantaris Tendon in Achilles and Calf Pain:
- Genetically close or invaginated plantaris tendon to Achilles.
- Rubbing and compression of the two tendons, aggravating symptoms.
- Increase in activity levels or sports.
Symptoms of Invaginated Plantaris Tendon in Achilles and Calf Pain:
- Pain on the inside of the Achilles radiating up into the midportion of the calf.
- Dorsiflexion and barefoot walking extremely uncomfortable.
- History of low grade calf strains.
- Recurrent symptoms even with a detailed load program.
- Thickened plantaris tendon on US in close proximity to Achilles tendon.
Treatment for Invaginated Plantaris Tendon in Midportion Calf Pain:
- Mini-invasive surgical treatment to release the plantaris tendon or separate the two tendons.
- Gradual load and rehabilitation program to strengthen the Achilles and calf muscle.
- Return to Achilles tendon and calf loading sports.
Interesting article for further reading
Midportion Achilles tendinosis and the plantaris
At Well Heeled Podiatry we are experienced in dealing with sports injuries and managing Achilles and calf pain.
A thorough biomechanical examination, along with clinical palpation, history taking and diagnostic testing will allow us to determine the cause of injury and an appropriate treatment regime.
