How is micro-fracture used in foot and ankle surgery?
The surface of every joint is covered with a smooth, glistening material called cartilage. Cartilage is an avascular structure that is supplied with oxygen and essential nutrients by the synovial fluid within the joint. Synovial fluid is capable of keeping healthy cartilage viable but lacks the capability to effectively repair damaged cartilage. Large defects in cartilage, whether due to injury, arthritis, or a combination of both, often requires repair by surgical fusion or joint replacement. In cases of focal injury, where only a small percentage of cartilage is damaged, a technique called microfracture can be used to restore cartilage.
Cartilage is supported by a layer of hard, dense bone called the subchondral plate. Deep to the subchondral plate lies the bone marrow, rich in pleuri-potential cells (stem cells) that have the capability to become bone cells, cartilage or other musculoskeletal components. In cases of focal cartilage defects, breaking through the subchondral plate and releasing these stem cells provides a way to resurface the joint with new cartilage.
Which foot and ankle joints are treated with microfracture?
Microfracture is used in foot and ankle surgery to restore focal cartilaginous defects of the talar dome and great toe joint. The images in this post show a focal defect of the first metatarsal head due to a condition called hallux limitus. Microfracture was used in this case in an attempt to resurface the first metatarsal head. Should microfracture fail to restore cartilage in this joint, joint replacement or joint fusion would be indicated.
How is microfracture performed in foot and ankle surgery?
Microfracture is performed by using a Kirschner wire or small drill. The technique is to drill through the subchondral plate. During the first few moments following completion of the surgery, blood rich in stem cells will flow from the marrow into the joint. These unique marrow based cells will act to form fibrocartilage within the joint defect.
Is microfracture universally successful in foot and ankle surgery?
The success or failure of microfracture in foot and ankle surgery depends upon a number of variables including the viability of the host's marrow cells and the extent of the injury to the cartilage. Although microfracture does not replace the original hyaline cartilage, the fibrocartilage created by the stems cells is often adequate to restore joint mobility and decrease pain.