Subchondral insufficiency fractures of the knee: review of imaging findings

Subchondral insufficiency fracture of the knee (SIFK) is a potentially devastating disorder that may progress rapidly to osteoarthritis with articular surface collapse. It should be suspected in the appropriate clinical setting, as in early stages it is usually indistinct on initial plain radiographs and magnetic resonance imaging is required for a definitive diagnosis. Outcome of SIFK depends on several factors, including the initial subchondral fracture size, patient BMI, degree of osteopenia, as well as early diagnosis and initial treatment. The purpose of this paper is to review the clinical presentation, pathophysiology, image findings, complications and outcome of SIFK.