What is Osteochondritis dissecans?

In this case, osteochondritis dissecans is a joint injury where the end of one bone has detached from the back of another bone. The cause of this condition is stopping blood flow to the end, which means the bone on the inside becomes soft. This causes a small portion of the bone to die and separate from the rest. Then, the piece of bone, along with cartilage covering and shielding the bone, breaks and separates.

The loose bone and cartilage can stay inside the socket or be pulled into the joint space, which then loses stability. The disease leaves a defect by separating the bone and the cartilage. The whole process of the disease can take months or even years, and the symptoms show very slowly.

Osteochondritis dissecans typically develops at the end of the thigh bone, knee, ankle, or elbow. However, it can also occur in other joints, such as the shoulder or hip.

Usually, osteochondritis dissecans happens in only one joint. An isolated lesion in a single joint is known as sporadic osteochondritis dissecans.

Who is susceptible to osteochondritis dissecans?

This is most commonly seen in children and adolescents aged 10 to 20 years, particularly athletes or highly active youngsters. The condition, however, may be evident in anyone regardless of age.

Osteochondritis dissecans are rarely found in more than one joint and may be familial, possibly in more than one family member (familial osteochondritis dissecans). People with this type of osteochondritis dissecans commonly have short stature and an early susceptibility to osteoarthritis, which is the breaking down bone and cartilage that covers the joints.

What causes osteochondritis dissecans?

While the causes of the rare nature of osteochondritis dissecans are still not in the catalogue, one of the possible explanations for this disease is the outcome of the fact that long-term repeated trauma or stress against the joint placed due to playing sports, for instance.

Familial osteochondritis dissecans is caused by inherited mutations to the ACAN gene. This gene is the origin of a protein in charge of cartilage building called aggrecan. Because of the mutation, this protein is unable to adequately assemble cartilage, which is thus weak and poorly organized. Yet it is unknown how such an insufficiency in cartilage potentially leads to the separation of the bone and the lesion.

What are symptoms of osteochondritis dissecans?

This may be asymptomatic if the detached bone and cartilage stay close to the more prominent bone. When symptoms are present, they can include all the following:

Pain, weakness, and swelling in a joint, often following physical or athletic activity.
Reduced range of motion, or decrease in the amount of distance a joint normally moves, and inability to move the arm or leg through a full range of motion, especially in relation to full extension. This is more common if the piece of bone and cartilage moves into the joint space.
Stiffness in the joint after rest.
Locking or catching of a joint so that it will not move in specific directions.
A clicking sensation when moving the joint.

A physician diagnoses osteochondritis dissecans using a physical examination of the nature of the joint. The doctor will further evaluate the joint's stability. Tests that are likely to be ordered include:

X-rays, which display the bone, help locate the lesion and reveal its size.
A magnetic resonance imaging test (MRI), taken in concert with an ultrasound, can produce quite clear images of the involved cartilage and show whether or not the avulsed bone and cartilage have inserted themselves into the joint space.
A computed tomography (CT) scan shows more detail of internal structures including bone, blood vessels, and soft tissues than traditional X-rays.
If familial osteochondritis dissecans is suspected, then genetic test can indicate changes in genes, chromosomes, and proteins.

How is osteochondritis dissecans treated?

In young children and teenagers, osteochondritis dissecans is a condition that tends to resolve spontaneously over time. They can use rest and absence from strenuous physical activities like running and jumping to alleviate pain and swelling. The doctor may recommend a non-prescription pain reliever/anti-inflammatory medication like ibuprofen (Advil®, Motrin®).

After six to 12 weeks, the joint will function normally again. The athlete should gradually return to sport through low-level activities (stretching, swimming, biking, or yoga).

If the healing is slow, he or she may advise you to use crutches, or may place a brace, splint or cast on the joint. They may also notify you to have physical therapy.

Your doctor may decide to recommend you undergo surgery if:

Rest and time do not reduce the pain and swelling.
Research suggests that the avulsed bone and cartilage are floating in the joint space.
The diameter of the avulsed bone and cartilage measures more than 1 centimeter.

The surgical procedure is usually arthroscopic, meaning it employs small instruments and a camera placed through small portals. There are three surgical procedures:

It is creating a hole through the affected bone and cartilage. This leads to paths for new blood vessels with oxygen, where healing occurs in the new bone.
Implantation of the excised bone and cartilage in position with the help of pins and screws.
Reattachment of the avulsed bone and cartilage with a graft to form healthy tissue in the damaged area. The bone and cartilage are obtained from another body part or a donor. Doctors can also get the patient's healthy bone and cartilage specimen to expand into the lab.

After the surgery, the patient will have to walk with crutches for nearly six weeks. Subsequently, they should undergo physical therapy, which may last up to two to four months, to become strong and develop the joint's range of motion. The patient might be allowed to regain their previously demanding athletic activities four to five months after the surgery.

Can osteochondritis dissecans be prevented?

It is sometimes difficult to prevent osteochondritis because its causes are unknown. Young children playing sports can take what measures they can to protect their joints, such as wearing pads and protective gear. They should also learn appropriate physical techniques in their sport, stretch and warm up before vigorous physical activity, and stretch and cool down afterward.

What is the prognosis (outlook) for someone with osteochondritis dissecans?

The outcome is much better in younger patients. A young patient may recover totally and resume previous levels of activities. However, the patient may have to forgo sports that require repetitive motions, such as pitching.

Adults are more likely to need surgical treatment of osteochondritis dissecans and less likely to recover completely from the condition. Adults are also more likely to develop osteoarthritis in the affected joint.

Osteochondritis dissecans typically do not recur after a person has healed. However, it may seem like the patient has healed at times because symptoms may disappear temporarily. It can come back later.