Osteochondritis dissecans of the knee usually affects young athletes but can occur in just about anyone who puts repetitive stress on their knees.

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Osteochondritis dissecans of the knee is a condition mostly affecting children and adolescents. Young athletes, dancers, and others who put repeated and forceful strain on their knees face higher risks of developing this condition.

The burden on your knee joint can affect the blood vessels in the area, causing very tiny fractures (microfractures) and leading to tiny areas of bone that die due to the limited blood flow, a disease called avascular necrosis in the bone and cartilage connection. This triggers pain and a less stable joint.

Sometimes rest or a brace is enough to allow your bone and cartilage to heal. But in some cases, surgery is needed to make sure your joint heals and your knee regains its strength and flexibility.

Read on to learn more about how to recognize symptoms of osteochondritis dissecans of the knee and what your options are if you receive a diagnosis of the condition.

Learn more about osteochondritis dissecans.

Osteochondritis dissecans most commonly affects your knee, but it can develop in other joints, such as your ankles and elbows. It occurs when part of the bone in your joint completely or partially separates from the cartilage, affecting the tiny blood vessels and causing the fragmented piece of bone to die. Your cartilage can also become damaged.

The site of the fracture, where the piece of bone breaks away from the rest of your bone, is called a lesion. A lesion is considered stable if part of the fragment remains attached to the “parent” bone. It’s classified as unstable if the fragment completely separates.

Osteochondritis dissecans of the knee usually affects just one joint, but in some cases, the condition can occur in both your knees.

The National Organization for Rare Disorders reports that most people who receive a diagnosis of the condition are between the ages of 10–15 years old.

Adults who receive a diagnosis of osteochondritis dissecans of the knee usually developed the condition when they were younger but never had severe symptoms or had the condition evaluated.

Osteochondritis dissecans of the knee affects the way your joint feels and how it functions. Common symptoms include pain and swelling that tend to worsen with activity.

Other symptoms can include:

  • your knee locking or catching when your leg is straightened
  • your knee “crumpling,” making it too unstable for standing or walking
  • limited range of motion in your knee

It’s not always clear why the condition occurs, though the American Academy of Orthopaedic Surgeons suggests that osteochondritis of the knee is similar to other repetitive strain injuries.

Sports that involve a lot of running and jumping or dance and other activities that put young knees through a lot of repetitive stress or trauma may raise someone’s risk of developing osteochondritis dissecans.

Low levels of vitamin D are also associated with osteochondritis dissecans of the knee. Some people may be genetically predisposed to the condition. Poor or reduced blood supply to your joint may also make your bone vulnerable to fracture and separation.

Osteochondritis dissecans can lead to several serious complications and long-term difficulties if not treated properly from the start. Chronic pain and arthritis can develop if your injury doesn’t heal, with or without surgery or other treatment.

Another possible complication is known as a “nonunion,” which means an injured bone fails to heal over time. This can cause further structural damage to your joint and reduced function in your knee.

The right treatment for osteochondritis dissecans of the knee depends on the location of your injury, as well as its severity. The condition may be treated surgically or noninvasively – not breaking the skin. Stable lesions may need only noninvasive treatments.

Noninvasive treatment

Conservative treatment options include:

  • a knee brace to help stabilize your joint
  • modifying your activity level or using techniques to put less stress on your knee
  • rest and avoidance of rigorous sports or other activities that put a strain on your knees

The lesions in children tend to heal without surgery, mostly because their bones are still growing and developing. Natural healing may be less likely in older teens and adults.

Surgical treatment

Surgical options vary depending on the needs of your lesion. The surgeon may drill a small hole in your parent bone to improve blood flow to the site and stimulate the healing process.

Other surgical options include grafting (attaching) bone and cartilage taken from elsewhere in your body onto the parent bone to replace the piece of bone that broke away. The fragment may also be reattached to the parent bone with a pin or screw.

Several factors affect the outlook for someone with osteochondritis dissecans of the knee, including age, the nature of their fracture, and how it’s treated. Younger individuals who receive treatment tend to have better outcomes and often full recoveries compared with people who first receive treatment as adults.

People who have stable lesions and are treated with conservative measures often experience full recoveries and can return to their usual activities. Unstable lesions treated surgically can experience success rates ranging from 30–100%. Even with successful treatment, people who received surgery are likely to develop osteoarthritis in their knees.

The success of surgical treatment for osteochondritis dissecans of the knee depends on these factors:

  • the stage of the lesion when it’s found
  • the size of lesion
  • the age of the individual having surgery

A doctor should do a physical examination that includes gentle movement of your knee to assess its range of motion and stability. Be prepared to talk about when you first noticed symptoms and describe them in some detail. Your healthcare team will also want to know what activities you do and what might have triggered your symptoms.

The other key part of diagnosing osteochondritis dissecans of the knee is through imaging. This may include an X-ray, MRI, or both. A 2019 study in the American Journal of Roentgenology suggests that MRI is especially helpful in assessing the stability of osteochondritis lesions.

Because the potential causes of osteochondritis dissecans of the knee aren’t fully understood, it may not be possible to prevent the condition from developing. But some strategies that may be helpful include:

  • learning proper techniques for your sport or activity to reduce the risks of all injuries
  • participating in a variety of sports or activities to avoid repetitive stress
  • warming up before activity and cooling down afterward
  • wearing pads, braces, or other protective and supportive gear

It’s also important that children and teens tell their parents, coaches, or other responsible adults if they start to experience any symptoms such as pain, swelling, or a weakening or change in the function of their knees.

Osteochondritis dissecans of the knee is a condition of the knee usually affecting young athletes. However, it can occur in anyone who is active and has repetitive stress on their knees. Treatment may include surgery, but some people recover without surgery.