Dr. Roemer, Chief Medical Officer, gave an invited podium presentation in the session on ‘MRI of articular cartilage and bone: areas of imaging confusion and practical solutions' entitled “Osteochondral injury, subchondral fractures and traumatic bone oedema: what is important and how do I describe it”.
The lecture included an overview of terminology, technical advances of MRI of cartilage and clinical relevance of osteochondral injury. Structural predictors of later outcomes will also be discussed.
Bone marrow contusions are frequently identified on MRI after an injury to the musculoskeletal system. These osseous injuries may result from a direct blow to the bone, from compressive forces of adjacent bones impacting one another, or from traction that occurs during an avulsion injury. Commonly these injuries resolve without long-term sequelae. However, they may also involve the cartilaginous surface with or without an associated fracture line defining these as osteochondral injuries, which may have a different prognostic relevance. Subchondral fractures have been implicated in the genesis of some destructive articular conditions whose cause was previously undetermined, such as rapidly progressive osteoarthritis or spontaneous osteonecrosis of the knee. Subchondral fractures may ultimately lead to bone collapse, secondary osteonecrosis and severe articular damage. It should be suspected in the appropriate clinical setting, as in early stages it is usually indistinct on initial plain radiographs and MRI is required for a definitive diagnosis. The fracture line usually appears as a band of low signal intensity in the subchondral bone plate, adjacent to the articular surface, most often surrounded by bone marrow oedema. As these injuries may be occult on radiographs, the differentiation of bone contusions from osteochondral injuries or subchondral fractures is possible only with MRI including fat-suppressed and non-fat suppressed sequences. While purely subchondral lesions may have a good prognosis if diagnosed early, disruption of the articular surface may lead to early degenerative alterations including focal cartilage loss and other features of osteoarthritis.