A
Penetrate the subchondral bone plate to release mesenchymal stem cells and form a fibrocartilage clot
B
Transfer autologous hyaline cartilage plugs into the focal defect
C
Secure a synthetic scaffold over the exposed subchondral bone
D
Induce thermal necrosis of the surrounding hyaline cartilage to stimulate regeneration
Explanation:Correct Option: A. Microfracture is a marrow-stimulating technique. By penetrating the subchondral bone plate with an awl, bleeding is induced. This allows pluripotential mesenchymal stem cells and growth factors from the bone marrow to form a 'super clot' in the defect, which eventually differentiates into repair fibrocartilage (predominantly Type I collagen, unlike native Type II hyaline cartilage). (Ref: Steadman et al., Oper Tech Orthop, 1997)