microfracture

noun

mi·​cro·​frac·​ture ˌmī-krō-ˈfrak-chər, -shər 

1

: a small or minute fracture in a material (such as bone)

2

: an arthroscopic surgical procedure for the repair of damaged articular cartilage that involves debriding loose and calcified cartilage and drilling small holes in the bone beneath so that blood and bone marrow flow through and form a clot over the area of cartilage damage which will eventually develop into replacement fibrocartilage

In a classic treatment for cartilage regeneration, known as microfracture, mesenchymal stem cells are released from marrow in the underlying bone to permeate the damaged cartilage area.

—Jacob Klein, Science