Colorado complex knee specialist Robert LaPrade MD, PhD. sits down to discuss how to read an MRI of an osteochondritis dissecans lesions, also known as an OCD lesion.

An osteochondritis dissecans lesion in the knee is a condition that is caused by a reduction of blood flow to the end of a bone within the knee joint. This condition occurs most often in adolescent males under the age of 25.

The first sequence of MRI scans in a coronal scan. Starting with the patella, as you go in you can see the femur forming and ultimately the OCD lesion. The lesion will appear as a disruption to the subchondral bone. In this case, there are some cystic changes deep to the OCD lesion as well as general swelling in the rim that forms around the lesion.

In addition to assessing the OCD lesion we want to make sure that the articular cartilage of the medial tibial plateau is still intact along with the ACL and verifying that there is a good cushion in the meniscus.

The next sequence in how to read an MRI of an osteochondritis dissecans lesion is the sagittal view. In this view we can see the meniscus and the OCD lesion. In this case, you can see disruption of the bone and some cysts forming near the OCD lesion.

The last view is the axial image. In this type of injury it is not just damage to the cartilage, but damage to the bone also occurs. This view shows the cystic changes and subchondral bone changes.