Sudden Onset of Knee Pain – Consider a Medial Meniscus Posterior Horn Root Tear

Meniscus Root Tear

The medial meniscus or inner shock absorber of the knee has attachment in the front (anterior horn) and the back (posterior horn).

The posterior horn or root can tear as a result of degeneration or trauma.

This typical presentation include:

  1. Sudden onset of severe  knee pain.
  2. Does not improve with pain killers.
  3. May be associated with a sudden “pop” when walking followed by the onset of pain.
  4. Typically in people older than 55.
  5. Knee swelling within the next 1 day.
  6. Pain is felt at the back of the knee.
  7. Pain on bending the knee or squatting. Most patients cannot squat due to this pain.

The physical examination may show some swelling in the knee joint. Typically these knees already have some pre-existing degeneration or osteoarthritis.

There is usually pain on pressing of the inner and posterior aspect of the joint line of the knee.  The patient may not be able to squat down.

X-rays may show some osteoarthritis which was probably pre-existing.

MRI scan may sometimes show a root tear.  One need to actively look for a posterior horn root tear on MRI scan if this diagnosis is suspected.

This is a video showing a 59 year old woman who has pre-existing mild knee pain which suddenly worsened severely about 2 weeks ago.  She does not remember any trauma or injury.  She does Yoga as a form of exercise.

She was not able to walk properly due to pain in her right knee.

There was some fluid in her right knee on examination.  Tenderness (pain) was found along the posteromedial aspect of her right knee.

X-rays showed mild osteoarthritic changes.

MRI scan showed a possible posterior horn root tear.

Posterior Horn Medial Meniscus Root Tear

Arthroscopy of her right knee was done.  It showed an incomplete tear of the posterior root of the medial meniscus. The tear was cleaned up with an arthroscopic shaver and the posterior horn was the medial meniscus was secured to the capsule using a Fast-Fix meniscus repair device.

The patient’s right knee pain improved significantly after this surgery.  She was able to walk the very next day.

For more information on knee pain and meniscus tears, please contact us at 683 666 36 or email

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