microfracture

Microfracture is a surgical technique used to treat focal articular cartilage defects, typically in the knee, ankle, or hip. It involves creating small holes or channels in the subchondral bone at the base of the defect to allow access to bone marrow elements. The goal is to induce the formation of repair tissue to fill the defect.

The procedure is usually performed arthroscopically. After debridement to stable borders, an awl or pick is used to penetrate the subchondral bone, generating 3-4 mm deep channels. Blood and marrow elements spill into the defect, forming a clot that eventually differentiates into fibrocartilage.

Indications and outcomes. Best for small-to-medium, focal defects (often below 2-3 cm2 in the knee) in younger patients with normal alignment and stable joints. Limitations include that the repair tissue is fibrocartilage, not hyaline cartilage, and may degrade with time, especially in high-demand situations. Long-term outcomes are more variable for larger lesions or those in older patients; risk of persistent symptoms or progression of osteoarthritis.

Recovery and alternatives. Postoperative rehab uses limited weight bearing and early motion; return to activity can take several months. Alternatives for larger defects or unsuitable joints include osteochondral autograft transfer, osteochondral allograft, autologous chondrocyte implantation, or matrix-induced methods.