In injuries to cartilage and subchondral bone, which sequence occurs?

• A. Vascularization of bone causes fibrin clot; Inflammatory cells act; Formation of granulation tissue in 2 weeks; Return of cartilage in 2 months
• B. No clot forms; No inflammatory cells; Immediate cartilage return
• C. Vascularization prevents healing
• D. Immediate scar formation only

Answer: (A)

Injuries to cartilage and the subchondral bone heal through a vascular-driven sequence. When the bone vascularizes after injury, a fibrin clot forms first, providing a scaffold for cells and signaling factors. Inflammatory cells then invade, cleaning debris and releasing mediators that kick off the repair process. Within about two weeks, granulation tissue forms as the tissue bridges the defect. Because cartilage itself is avascular, true restoration of hyaline cartilage isn’t immediate; instead, repair tissue that can resemble cartilage—often fibrocartilage—develops and becomes more evident around two months. This sequence reflects how subchondral bone healing supports overall repair of the joint surface.

The other options don’t fit because they imply no clot or inflammation, claim vascularization prevents healing, or suggest only immediate scar formation, which contradicts the established healing stages described above.