What is Osteochondritis Dissecans?
Osteochondritis dissecans (OCD) is a pathologic process that affects the subchondral bone that then secondarily affects the overlying articular cartilage and can progress to separation and fragmentation of the cartilage. OCD most commonly occurs in the knee. When OCD occurs in the knee, it most likely affects the lateral aspect of the medial femoral condyle. The lateral femoral condyle and the patella can also be affected. Other joints that can be affected include the elbow or ankle.
Pathology of OCD usually shows avascular necrosis of the subchondral bone and varying degrees of ischemia and fibrosis of the overlying hyaline cartilage. When there is failure of both the bone and the cartilage to heal, there is increased risk of early osteoarthritis.
What Are The Typical Symptoms of Osteochondritis Dissecans?
When present within the knee, patients will typically have the complaint of deep knee pain that can localize to the medial or lateral joint line. There can be swelling, tenderness over the femoral condyles, quadriceps atrophy (muscle wasting) and decreased range of motion. If the lesion has become severe enough that a fragment has broken off, the patient can develop mechanical problems including catching and locking of the knee.
What Types of Activity Cause Osteochondritis Dissecans?
Though the exact cause of OCD is not known, it seems that repetitive microtrauma is the most likely cause. Children or adolescents with high activity level can be at risk for OCD. Sports that are more likely to be associated with high frequency of knee injuries (OCD included) include soccer, football, and basketball. Sports associated with elbow injuries include baseball and gymnastics.
How Is Osteochondritis Dissecans Evaluated?
Plain radiographs of the affected joint are obtained first. Even early lesions can be identified by this imaging modality. MRI can also be useful as a secondary study to further determine the size of the lesion, the integrity of the articular cartilage and the presence of any fragments. In severe cases, especially if the OCD lesion is unstable appearing, arthroscopy may be performed to further evaluate the lesion.
Osteochondritis Dissecans Treatment Options
Treatment includes nonoperative and surgical options. Treatment depends on the skeletal maturity of the patient, severity of symptoms, lesion size and if the lesion is stable or unstable.
Nonoperative management is a period of non-weightbearing and immobilization, then a period of strict activity restriction and physical therapy for 3-6 months. The lesion is usually imaged approximately every 3 months to confirm that healing has begun. If healing has not started with 3-6 months, surgery is considered.
Surgical management consists of an arthroscopic evaluation of the joint, then either transarticular or retroarticular drilling to stimulate bony healing. For those patients with fragments, sometimes fixation of the fragment back into place can be performed. But, if the fragment has become loose in the joint space, it is most likely removed and cartilage repair and restoration is completed.
By Erin Green, DO and Mo Mortazavi, MD
References:
Hergenroeder, A. C., & Harvey, B. S. (n.d.). Osteochondritis dissecans (OCD): Clinical manifestations and diagnosis. Retrieved August 19, 2018, from https://www.uptodate.com/contents/osteochondritis-dissecans-ocd-clinical-manifestations-and-diagnosis?search=osteochondritis dissecans&source=search_result&selectedTitle=2~27&usage_type=default&display_rank=2
Kliegman, R. M. (2016). Nelson textbook of pediatrics (20th ed., Vol. 2). Philadelphia: Elsevier.
Osteochondritis Dissecans [Digital image]. (n.d.). Retrieved August 23, 2018, from https://orthoinfo.aaos.org/en/diseases–conditions/osteochondritis-dissecans/
