Osteochondral injuries.

Osteochondral injuries are an important type of musculoskeletal trauma that can lead to disabling arthritis if not recognized and treated appropriately in the early stages. The anatomic configuration and biomechanical function of a joint are important for understanding its particular pattern of osteochondral injury and the resultant imaging appearance. The imaging of osteochondral fractures and osteochondrosis dissecans (OCD) is reviewed in this article, with particular attention to differentiating surgical and nonsurgical lesions on the basis of their appearance with advanced imaging modalities. Computed tomography (CT) and magnetic resonance imaging (MRI) have improved both the sensitivity and specificity for detection and characterization of osteochondral injuries. MRI is currently the modality of choice for the detection and staging of osteochondral injuries. It has the greatest sensitivity owing to its ability to depict marrow edema and directly assess the fracture clefts of stage 3 lesions, as well as the morphology of articular cartilage. Newer strategies for differentiating stable from unstable osteochondral fragments include MR arthrography and intravenous contrast-enhanced MRI.