Bocc-
Degenerative change in the medial compartment applies to the articular cartilage, also called osteoarthritis in a lot of the information on the web.
Mucinous degeneration of the meniscus partains to cyst like lesions I believe.
Go to any of the search engines and put the phrases in search box and you will find a multitude of information.
Best of luck!
Lezlee