Osteochondral Defect (Osteochondritis Dessecans)
What is it? An osteochondral defect (OCD) is a focal area of necrosis of the subchondral bone. It can occur in many areas, including the femoral condyles, talar dome and capitellum of the humerus.
How does it present? The patient will often complain of vague knee pain with or without activity. They may develop swelling related to activity and have a sense of catching in their knee if a piece of bone has broken loose in the joint.
Common exam findings: You may see an effusion, or the patient may have joint line tenderness. If they have a loose fragment, they may have locking or decreased range of motion.
Tests and treatment: If an OCD lesion is suspected you should get knee x-rays with a tunnel-view (knee in flexion). The tunnel view will better view the posterior aspects of the femoral condyles, where the lesions may be. If an OCD lesion is seen on x-ray, a magnetic resonance imaging (MRI) should be performed to stage the lesion for appropriate management. If no lesion is seen, but one is still suspected, the MRI should also be done for evaluation. OCD lesions are staged I to IV. Stage I lesions are intact but have a mildly irregular articular cartilaginous surface. Stage II lesions have mild separation and worsening articular surface irregularity. Stage III lesions are partially detached and stage IV lesions are fully detached and can leave a loose body in the joint. Depending on patient age and circumstances, stage I and II lesions can be attempted to be treated conservatively by decreasing activity to only pain free activities for six to eight weeks. Those that continue despite this and stage III and IV lesions should be referred to orthopedics.