microfracture

noun

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

1

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

Microfractures are the result of normal physical activity. Hence, the widespread occurrence of trabecular microfracture in cancellous bone implies that a reasonable rate of microfracture is physiologically tolerable.

—Nicola L. Fazzalari, Calcified Tissue International

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