The meniscus is a crescent-shaped structure positioned on the tibial plateau within the knee joint. There are two in the stifle joint, one on the medial surface (towards the body midline), and one on the lateral surface (away from the body midline). They help to cushion the end of the femur and provide additional support and stability.
In cases of CrCLD, as the femur slides down the tibial plateau, the tibia can rotate inwards and cause uneven pressure on the medial meniscus, particularly the tail end. This excessive force can crush the medial meniscus and cause tears or displacement.
Meniscal injury is common with complete cruciate ligament rupture and is a source of significant pain.
The meniscal cartilages are inspected and assessed during the procedure for all knee surgeries. If the medial meniscus appears damaged, then the damaged portion can be removed to alleviate pain. In some cases, the whole of the medial meniscus is removed due to damage. While this does compromise stifle joint stability to a small degree, it is preferable to leave a damaged meniscus in the stifle that causes ongoing pain.
Damage to the meniscal cartilages can still occur even after surgery. These are called “late meniscal tears” and can occur in about 10% of cases. Some surgeons elect to perform a “meniscal release” to try to prevent late meniscal tears. This is done by cutting the attachment of the tail end of the medial meniscus, so it can freely move over the tibial surface and is less likely to be crushed by pressure. This however, also means the meniscus can’t perform its job as well as before. Your vet may give you the option to elect to perform a meniscal release as a preventative measure.