Osteochondritis dissecans (OCD) is a pathologic change seen in many joints but most commonly seen in the knee. The cause is thought to be due to trauma and a reduction in the blood supply to the bone. The pathophysiology involves the loss of blood supply in an area of bone underlying cartilage. Without blood supply, the bone dies and the cartilage breaks loose and arthritis develops. OCD is the most common cause of loose bodies in the knee. There are two distinct subgroups of patients: the skeletally mature and the skeletally immature.

What are some of the symptoms seen in OCD?
The patient will complain of pain, catching, locking, swelling, giving way. They may feel something moving inside their knee.

Will x-rays be taken?
X-rays will usually show an OCD lesion. This is typically seen on the medial femoral condyle (inside bump on the femur). A MRI is used to determine if the lesion is attached or not attached to the underlying bone.

What is the treatment for an OCD?
The treatment of OCD depends entirely on the skeletal maturity of the patient and if the piece of cartilage is loose or not loose. If the lesion is loose in any age, an arthroscopy needs to be performed to evaluate the cartilage and either fix or remove the loose piece. If the patient is skeletally immature (still growing) and the OCD is attached, then activity modification for 3 months will usually allow the lesion to heal. If a patient is skeletally mature, arthroscopy is necessary because healing cannot occur without medical intervention.