Knee Pain
Osteochondritis Dissecans
Osteochondritis dissecans (OCD) is a condition that develops in joints, most often in children and adolescents. It occurs when a small segment of bone begins to separate from its surrounding region due to a lack of blood supply. As a result, the small piece of bone and the cartilage covering it begin to crack and loosen.
The most common joints affected by osteochondritis dissecans are the knee, ankle and elbow, although it can also occur in other joints. The condition typically affects just one joint, however, some children can develop OCD in several joints.
In many cases of OCD in children, the affected bone and cartilage heal on their own, especially if a child is still growing. In grown children and young adults, OCD can have more severe effects. The OCD lesions have a greater chance of separating from the surrounding bone and cartilage, and can even detach and float around inside the joint. In these cases, surgery may be necessary.
The exact reason why blood flow may become interrupted in a segment of the bone is unknown. However, osteochondritis dissecans has been linked to:
Repetitive trauma or stress on a joint, such as from playing sports
Genetic predisposition in some patients
Depending on the joint that's affected, signs and symptoms of osteochondritis dissecans might include:
Pain. This most common symptom of osteochondritis dissecans might be triggered by physical activity — walking up stairs, climbing a hill or playing sports.
Swelling and tenderness. The skin around your joint might be swollen and tender.
Joint popping or locking. Your joint might pop or stick in one position if a loose fragment gets caught between bones during movement.
Joint weakness. You might feel as though your joint is "giving way" or weakening.
Decreased range of motion. You might be unable to straighten the affected limb completely.
To diagnose osteochondritis dissecans, an orthopedic specialist will take a medical history and perform a physical exam on your child. The doctor will check for pain along the affected joint line and may order an x-ray or MRI to help them see the joint.
Diagnosing OCD of the knee, elbow, and ankle
To diagnose osteochondritis dissecans, your child’s doctor will assess the affected joint for any swelling or tenderness. They will also test the range of motion of the joint. This may include specialized manipulations of the joint, such as a Wilson test of the knee, to see if a particular rotation of the knee causes pain. To diagnose osteochondritis dissecans of the elbow, ankle or another joint, your child’s doctor will perform similar specialized manipulations.
Testing for osteochondritis dissecans
Various tests may be used to confirm the osteochondritis dissecans diagnosis.
X-rays: Typically, multiple x-ray views are taken to confirm and assess the extent of the injury. X-rays may also be taken of the same joint on the other limb as a basis for comparison.
MRI (magnetic resonance imaging): An MRI can show whether the loose piece is still in place or has moved into the joint space.