What is subchondral insufficiency fracture of the knee? Describe its MRI appearance.
Subchondral insufficiency fracture of the knee is characterized by sudden onset of pain in the absence of trauma. It usually involves the weight-bearing surfaces and most commonly occurs in the central weight-bearing surface of the medial femoral condyle. In contrast to OCD, this entity is more common in elderly women in the sixth or seventh decades of life. It was formerly known as spontaneous osteonecrosis of the knee.
The typical MRI appearance is a low T1-weighted signal intensity focus just beneath the articular surface with a large amount of bone marrow edema seen on T2-weighted images
