MR Imaging of the knee on a young patient with osteochondritis dissecans (OCD)
OCD is the term first utilized in 1887 to describe the occurrence of a progeny osteochondral fragment separated from the parent bone. The etiology remains controversial considering genetic, traumatic, and vascular causes. In the knee, OCD most commonly occurs in the central aspect of the medial femoral condyle (blue arrow), followed by the lateral femoral condyle, the trochlea, and the patella.
Onset is between childhood and middle age, with the majority of patients being between 10 and 40 years of age, with approximately a 2:1 male to female ratio.