[Subchondral insufficiency fractures of the knee : Navigating the complex terminology landscape].

CLINICAL/METHODICAL ISSUE: Subchondral insufficiency fractures (SIF) occur without adequate trauma to the weight-bearing joint surfaces due to repeated physiological loading and occur predominantly in older people.

STANDARD RADIOLOGICAL

METHODS

Magnetic resonance imaging (MRI). Radiographs.

METHODOLOGICAL INNOVATIONS: MRI is the best method for the detection, follow-up, and assessment of the prognosis of subchondral insufficiency fractures.

PERFORMANCE: The typical MRI findings of SIF are bone marrow edema, a subchondral hypointense fracture line, and possibly a subchondral hypointense area on T2-weighted sequences. Subchondral cortical deformity and a fluid-filled cleft indicate advanced SIF with a poor prognosis.

ACHIEVEMENTS AND PRACTICAL RECOMMENDATIONS: Subchondral insufficiency fractures can heal spontaneously or progress to collapse. The task of radiology is to distinguish between lesions that heal (simple subchondral insufficiency fractures) and lesions that progress unfavorably (subchondral insufficiency fractures with osteonecrosis).