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Definition
Osteochondritis Dessicans (OCD) is a disorder of cartilage and the underlying subchondral bone which becomes avascular in nature. It is thought to be the result of multiple episodes of microtraumatic events and there is possibly a genetic component as well. The most likely involved joints are the knee, the elbow, and the ankle. The most commonly involved area is the lateral aspect of the medial femoral condyle. The lateral condyle is affected in 15-20% of the cases involving the knee. The patella is rarely involved.
It is characterized by pain and swelling and occasional locking episodes of the knee. The patient occasionally complains of the knee or ankle giving out.
It is likely the result of microtrauma in the active young patient. It is most commonly seen in the 10-15 year age groups, although it can also been seen in older adults in the ankle. Baseball players and gymnysts are particularly at risk for OCD of the elbow due to the increased stresses about the joint.
It is sometimes by degenerative changes to the joint several years down the road if th lesion is large and fails to heal appropriately.
Diagnosis is suspected clinically by patients in the 10-15 year age group that have pain and giving way in the knee with a history of swelling. As stated above, overhead athletes are at risk of OCD in the elbow and appropriate films should be taken in this age group. The patient will be most tender over the lateral aspect of the medial femoral condyle and may have a mild effusion of the knee.
Imaging should be obtained to diagnosis and stage the disease. Plain x-rays of the knee will help to rule out the disorder, and it is critical to get tunnel views of the knee (shows lesion best) as well as an AP and lateral. Elbows should be evaluated with AP, lateral, and 45 degree AP views. The ankle should be evaluated with AP, lateral, and mortise views. MRI should also be obtained after diagnosis is obtained to help stage the lesion and determine whether healing is taking place.
Treatment options depend on the age of the patient, the stage of the lesion, and the area of involvement. Younger patients can often times heal early stages of the disease and can therefor be treated with activity modification and observation. Adolescents and adults have less of a chance of healing an OCD lesion and will likely need surgical drilling +/- fixation.
References
Miller, Mark. Review of Orthopaedics. Saunders Elsevier. Philedelphia, 2008. pp 260-261