Osteochondritis Dissecans (OCD) of the Femoral Condyles

Osteochondritis dissecans (OCD) is a relatively rare cause of knee pain and dysfunction. Despite being described in 1887, the exact etiology is not definitively known. Numerous theories as to the cause have been described, including abnormal inflammatory response, vascular occlusion, trauma, repetitive micro-trauma, as well as heriditary/genetic abnormalities. The condition is most common in young men between 10-20 years of age. The most common location is on the distal femur, and while OCD can occur on any of the articulating portions of the knee, the lateral portion of the medial femoral condyle is where it is diagnosed most frequently.

 OCD can often be overlooked in adolescent patients because initial complaints are intermittent and vague anterior knee pain. There is some evidence that if the diagnosis can be made when a patient is still skeletally immature, that protected weightbearing and activity modification can lead to healing and complete resolution of the process. However, in many cases, the OCD lesion progresses through stages of edema (swelling) of the bone surrounding bone, bone resportion in and around the lesion, necrosis (death) of the bone, and eventual fracture, collapse, and instability of the necrotic fragment.

Arthroscopic video of an unstable osteochondritis dissecans lesion of the lateral femoral condyle, which when removed, leaves a large defect in the lateral femoral condyle

For symptomatic patients with an unstable OCD lesion, attempts to get the fragment to heal can be considered. The procedures can include bone grafting and internal fixation of the fragment. This procedure seems to be more successful in skeletally immature patients and those without destruction and fragmentation of unstable bone-cartilage piece. Once the fragment has broken into several pieces, then procedures that retain the fragments are less predictable.

There are several different cartilage restoration techniques that can be considered once the fragment is not salvageable. Given the loss of cartilage and bone, my preferred treatment is to do an osteochondral allograft transplant ( transplant live bone and cartilage from a donor ). Osteochondral allograft transplantation for OCD of the femoral condyles has a success rate of approximately 85-90%.