Osteochondritis Dissecans

Abstract

After participating in this activity, the diagnostic radiologist should be better able to diagnose the various imaging appearances of osteochondritis dissecans and to identify differential diagnoses.Osteochondritis dissecans (OCD) is a common cause of joint pain in skeletally immature and young adult patients. Various pathologic conditions can mimic OCD in large and small joints. This article is a review of the pathophysiology, common imaging fi ndings, and treatment options of OCD. Several common mimickers of OCD, organized by joint, also are presented. PathophysiologyThe exact etiology of osteochondritis dissecans (OCD) is unclear, although several proposed pathologic mechanisms have been described in the literature. OCD is subdivided into juvenile and adult forms.The juvenile form of OCD occurs in skeletally immature patients. These patients are typically 5 to 15 years of age, and their physes are open. Several proposed etiologies for juvenile OCD include genetic predisposition, acute trauma, ischemia, and ossifi cation center abnormalities. 1 The authors favor the pathophysiologic process in which osteochondritis represents a normal variant ossifi cation center adjacent to a region of abnormal physis. Repetitive microtrauma may injure the articular cartilage, subchondral bone plate, and subchondral bone about the variant ossifi cation center. Given the adjacent region of abnormal physis, there is altered ability to lay down normal reparative bone.The adult form of OCD occurs in the skeletally mature patients. The physes are closed in these patients. Adult OCD may form de novo or result from the sequelae of juvenile OCD. 2 Imaging FindingsA report of the imaging fi ndings of OCD should contain a description of the integrity of the articular cartilage, subchondral bone plate, and subjacent subchondral bone. The stability of OCD is an important factor infl uencing treatment options and management. Stable OCD may be treated conservatively, whereas unstable OCD requires surgical intervention. The majority of adult OCD is unstable, whereas approximately 50% of juvenile OCD is stable and will heal with conservative therapy. V o l u m e 3 6 • N u m b e r 2 4 N o v e m b e r 3 0 , 2 0 1 3Lippincott Continuing Medical Education Institute, Inc., is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Lippincott Continuing Medical Education Institute, Inc., designates this enduring material for a maximum of 1.5 AMA PRA Category 1 Credits™. Physicians should only claim credit commensurate with the extent of their participation in the activity. To earn CME credit, you must read the CME article and complete the quiz and evaluation on the enclosed answer form, answering at least seven of the 10 quiz questions correctly. This continuing medical education activity expires on January