There are 2 menisci (the medial meniscus and the lateral meniscus) in each knee that serves as cartilage cushions or shock absorbers (images courtesy of the University of Georgia Educational Resources Center).
The medial meniscus is commonly torn in dogs that have complete CCL rupture. The lateral meniscus is rarely, but sometimes, torn in dogs. An important part of treating dogs with CCL rupture is assessing the menisci and making sure they are not torn. The best way (most likely to detect tearing and minimally invasive) to assess the menisci is with arthroscopy. If they are torn, the torn portion should be removed, or in very rare instances, repaired.
The following 3 photos and video show a normal medial meniscus.
Following removal of the torn portion of meniscus the remaining meniscus can be seen (within the left side of the image to the right) and the femur (in the upper portion of the image to the right) can now comfortably rest on the tibia (lower portion of image below). Note that the cartilage in this dog’s knee is still in good health and removal of the meniscus does not equate to “bone on bone” contact.