Subchondral bone edema/insufficiency fracture of femur
A subchondral insufficiency fracture is a type of stress fracture that occurs when bone underlying the cartilage in a joint is unable to bear stresses normally subjected to the joint. It usually affects the inside of the knee or the medial compartment which bears more stress and may involve the medial condyle of the femur. Pain is usually sudden in onset, not associated with an injury and continues for weeks or months. The subchondral bone shows changes detectable on an MRI. Edema is usually present in the region.