Subchondral drilling is a surgical procedure where small holes are drilled through damaged joint cartilage into the bone marrow of the underlying bone.
Concept of subchondral drilling
The concept behind this procedure, which was originally known as Pridie drilling, is that drilling into the bone marrow allows the release of bone marrow cells into the cartilage area which have the potential to form a protective 'fibrocartilage' layer over the defect.
Because the high speed drill can cause heating of the bone, and consequent damage, the procedure has largely been replaced with less damaging techniques such as microfracture.
Subchondral drilling for articular cartilage repair: a systematic review of translational research. Gao L, Goebel LKH, Orth P Cucchiarini and Madry H. Dis Model Mech. 2018 Jun 1; 11(6): dmm034280.