Knee menisci are important stabilisers of the knee joint, and damage can cause pain and also feelings of instability.
First published in 2013, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)
Before we progress, let's clarify that what people call 'knee cartilages' are in fact the shock absorbers of the knee known medically as 'menisci' (singular='meniscus').
The following is a list of the more common 'knee cartilage' (meniscus) problems:
Meniscal tear
The meniscus may be torn in an injury, usually a twisting injury. There may be severe pain at the time. Maybe some swelling due to bleeding inside the joint. May progress to a feeling of instability and joint line tenderness.
Meniscal avulsion
The ends of the meniscus may be ripped up from their attachment to the underlying tibia bone, or the meniscus may tear away from the capsule at the side of the joint.
Meniscal degeneration
The meniscus wears out, becoming friable at its edges and less effective as a shock absorber.
Displaced tear with locking
A specific type of tear of the meniscus, where the fragment flips over and locks the joint. This is the common cause of a knee which cannot fully straighten after and injury.
Broken off fragment with loose body
If the torn fragment breaks off it may float in the joint as a 'loose body', and cause catching or locking.
Meniscal cyst
A fluid-filled lump which you can feel at the joint line. Arises from the meniscus, often from a pre-existing horizontal cleavage tear (a hidden horizontal tear).