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Knee Pain

Posterior Horn Medial Meniscus Tear

Minute Read

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2 weeks ago

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by james

What is the posterior horn of the meniscus?

The meniscus is a thick cartilage structure that sits between the bones of the knee. It has the shape of two C’s. The medial meniscus is the C shape on the knee’s inner side, and the lateral meniscus is the C shape on the outer side of the knee. The posterior horn it the back portion of the menisci at the end of the curve, where it tapers into a horn shape. There is a posterior horn on both the medial and lateral menisci. There is also an anterior horn at the front of both menisci, the middle portion is called the meniscus body.

The blood supply is good to the outer third of both menisci but is less well perfused further into the middle. This is because the blood supply comes from where the meniscus is attached to the joint capsule surrounding the joint. This has an impact on the health and healing ability of the meniscus. Injuries to the outer rim tend to be less problematic, heal well and pain will last less time, whereas injuries to the middle portion can be more problematic and may never heal.

Diagram of meniscus with posterior horn marked

Functions of the Meniscus, (Fox et al, 2012):

 

  • Stability to the joint as it is thicker on the outer rim and thinner in the middle, therefore creating a deeper surface on top of the relatively flat tibial plateaux for the femur to sit in, which has a relatively rounded end
  • Cushioning the joint as it is made of thick cartilage which is effective at absorbing impact
  • Distribute weight across the joint, as there is flexibility in the cartilage it is able to disperse weight over a larger surface area
  • Lubrication and nutrition of the joint, there are micro canals in the menisci which can transport synovial fluid and nutrition into the joint

Can a posterior horn medial meniscus tear heal?

The posterior horn of the medial meniscus is the most common part of the meniscus to injure. The type of tear, the blood supply to the area that is injured, as well as the health of the individual and the tissue determines the likely hood of effective and efficient healing. If the tear is small and simple in the outer part of the meniscus, it is likely to heal and recover in 6-8 weeks. If the healing process is not sufficient and symptoms persist, the decision may be taken to operate to either remove the damaged tissue or repair the damaged tissue. The above factors will be considered to make this clinical decision. Typically surgery to repair will only be undertaken in areas with good blood supply as there is a good chance for it to heal. Recovery from a meniscus repair will be much longer, 3 to 6 months, than a meniscectomy where the damaged cartilage is removed, 3 to 6 weeks.

Sometimes a brace will be recommended to offload the injured area and facilitate the healing process. You can read about our recommendations in another article: Knee Brace for Meniscus Tear.

Diagram of different meniscus tear types

What are the Different Types of Meniscus Tear?

  • Radial tears
  • Flap or Parrot-beak tears
  • Incomplete, intrasubstance tear
  • Bucket-handle tears
  • Horizontal, cleavage tears
  • Complex, degenerative tears

What Causes a Posterior Horn Medial Meniscus Tear?

A meniscus tear is caused by excessive force through the knee joint. It is commonly a rotational force, or sudden acceleration or deceleration through the knee joint that will cause a tear. But a simple movement such as a deep squat especially if there is high weight can also result in a tear. Causes of tears of the posterior horn of the medial meniscus are more likely to occur when the knee is in deep flexion, such as crouching and twisting.

 

Picture of two football players

Common sports for acute meniscus injuries are football, rugby, skiing, wrestling, basketball, baseball, and other sports with high volumes of jumping and running with sudden changes of direction or speed. In some cases, this injury can occur with or following an injury to the ACL as if the knee has excessive forward movement, greater stress will be applied to the meniscus.

Other risk factors for degenerative tears include being over the age of 60 years, men being more at risk than women, occupations that require frequent kneeling and squatting, and frequent stair climbing (Snoeker et al, 2013).

Physiotherapy with James McCormack

This is not medical advice. We recommend a consultation with a medical professional such as James McCormack. He offers Online Physiotherapy Appointments for £45.

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