How does cartilage grow?

Factual Questions
1

My wife has been diagnosed with a torn meniscus. The orthopedist said the treatment is to arthroscopically snip the tear so that the flappy edges are not rubbing on nerves in surrounding tissue (I am paraphrasing as a layman.) I asked him why don’t they just sew the tear up. He said that the blood supply to the meniscus is around the edges, and if they make a repair to the center, it won’t heal.

If it has no blood supply and therefore can’t heal, how did it grow to be there in the first place?

2

Cartilage grows via a process called chondrogenesis, which secretes the molecules that form the extracellular matrix. There are two specific types of cartilage growth: Appositional growth occurs when chondroblasts secrete new matrix along existing surfaces and this causes the cartilage to expand and widen. In interstitial growth, chondrocytes secrete new matrix within the cartilage and this causes it to grow in length.

Feel free to correct me if I got any of this wrong.