Description of Posterior Horn Medial Meniscus Tear
The posterior horn of the medial meniscus is that portion of the medial meniscus in the back part of the knee. It varies from the main weightbearing portion of the meniscus up to where it attaches on the tibia at its lateral aspect, called the root attachment.
The posterior horn of the medial meniscus is the most important weightbearing portion of the meniscus. While the medial meniscus absorbs 50% of the weight transmitted across the medial compartment, the posterior horn of the medial meniscus is the most important portion of the meniscus that provides the shock absorbing capacity.
Symptoms of a posterior horn medial meniscus tear:
- Swelling and stiffness, increases gradually from hours to days after injury
- Catching or locking
- An inability to straighten the knee
- Pain in the back of the knee with deep squatting
Because the posterior horn of the medial meniscus absorbs most of the weight of the medial compartment, it is also by far the most frequent area that a meniscus tear occurs in. This is especially true in patients who have an ACL tear, where this portion of the meniscus then acts as the main structure to prevent the knee from slipping forward (anteriorly).