Osteochondritis dissecans occurs when a fragment of bone in a joint separates from the rest of the bone because its blood supply is faulty, and there is not enough blood to maintain it. It often affects the knee or the elbow.
Sometimes, the separated fragment stays in place or repairs on its own. However, in the later stages, the bone can splinter and fall into the joint space, resulting in pain and dysfunction. These fragments are sometimes called “joint mice.”
The exact prevalence is unknown, but there may be between 15 and 29 cases in every 100,000 people. It is more common in males, especially those between the ages of 10 and 20 years who are physically active.
However, the incidence is increasing in females.
It usually affects teens and young adults, but it can occur in younger children who are active in sports.
Signs and symptoms
OCD can cause pain and discomfort in the knee and other joints.
Osteochondritis dissecans (OCD) can occur in different joints, including the hip and ankle, but 75 percent of cases affect the knee.
Signs and symptoms of OCD include:
inflammation, swelling, and soreness in the joint
catching and locking in the joint during movement
reduced range of movement in the joint
crepitus, a grating, cracking, or popping sound when moving the joint
weakness in the joint
effusion, or abnormal collection of fluid in the joint area, leading to swelling
pain, especially after physical activity
stiffness after a period of inactivity
The exact cause is unknown, but they may include:
Ischemia: a restriction of blood supply starves the bone of essential nutrients. The restricted blood supply is usually caused by some problem with blood vessels, or vascular problems. The bone undergoes avascular necrosis, a deterioration caused by lack of blood supply. Ischemia usually occurs in conjunction with a history of trauma.
Genetic factors: OCD sometimes affects more than one family member. This may indicate an inherited genetic susceptibility.
Repeated stress to the bone or joint: this can significantly increase the risk of developing OCD. Individuals who play competitive sports are more likely to regularly stress their joints.
Other factors may be weak ligaments or meniscal lesions in the knee.
A person who experiences the symptoms of OCD in a joint should seek medical advice. An early diagnosis can mean more effective treatment and a lower risk of complications.
The doctor will carry out a physical examination and ask the patient about their medical history, family history and lifestyle, including sporting activities.
There may be some imaging tests, such as an X-ray, CT, MRI scan, or ultrasound. This may show whether there is any necrosis, or tissue death, or loose fragments. A bone scan may also be recommended.