Examination of the meniscus during surgery for cranial cruciate ligament rupture. The meniscus and stifle may also be examined in a minimally invasive manner by arthroscopy
Meniscial injury in dogs can be associated with cranial cruciate ligament rupture in the stifle (knee) joint.
Incidence of meniscal tears is at least 30-40% in association with Cranial Cruciate ligament (CCL) tears and is more common in chronic CCL lesions, hence tears are more likely to occur with "cruciate disease"
The menisci are c-shaped fibrocartilages that sit between the femoral and tibial condyles. They play an important role in stifle stability, load distribution and lubrication. They are triangular in cross section. The inner two-thirds of the menisci are avascular, which contributes to poor healing when they are damaged. Short ligaments attach the medial meniscus to the tibia caudally and cranially. The medial meniscus also has a peripheral attachment to the medial collateral ligament. The lateral meniscus differs in that there is no peripheral attachment to the adjacent collateral ligament, and caudally it attaches to the femur. The menisci are loosely attached to each other by the cranial intermeniscal ligament, which lies over the insertion of the cranial cruciate ligament
The tibial plateau is not perpendicular to the line between the centre of motion of the hock and stifle. Therefore, on weight bearing, the femoral and tibial articular surfaces are not only compressed together, but an additional cranially directed force is generated (the femoral condyles effectively want to ‘roll down’ the tibial plateau). This force is known as Cranial Tibial Thrust. It is therefore an internally generated force that is resisted by the cranial cruciate ligament, the caudal pole of the medial meniscus and the caudal thigh muscles. Loss of the cranial cruciate ligament places additional strain on the meniscus and frequently the medial meniscus become trapped and then tears.
These torn sections must be removed at the time of surgery, or a painful lameness will persist.
Late meniscial injury may occur following a LFS, TTA or TPLO surgery even when the meniscus was found to be normal at the time of the original surgery. This necessities a more minor surgery to remove the torn meniscial section. Frequently this may be assessed arthroscopically.