What is it about ?
Osteochondritis dissecans of the knee is a joint injury in which a fragment of bone covered with cartilage breaks away from the surface of the knee joint:
- a fragment of the lower part of the thigh bone (femur);
- or a fragment of the upper part of the leg bone (tibia).
The cause is often poor blood circulation in the leg, which leads to necrosis and the detachment of a piece of bone. The problem can also arise after a knee injury.
How to recognize it?
It often starts with a period of discomfort and vague pain in the knee, especially when putting all of your weight on one leg, for example if you exercise intensely. As long as the fragment does not come off, complaints remain quite limited.
When the piece of bone comes loose, symptoms can increase quickly and dramatically. Signs of joint inflammation appear: the knee swells, extension and especially flexion movements of the knee are limited; sometimes the knee becomes red and hot and the pain increases.
If the movable piece of bone gets stuck between the surfaces of the joint, the knee can suddenly lock up. Full knee flexion and extension becomes impossible.
Smaller pieces of bone, which do not come off entirely, can lead to more chronic problems, such as swelling and varying pain when you lean on our leg.
How is the diagnosis made?
When examining the knee, the doctor sees signs of inflammation and possibly blockage. It can trigger pain by performing certain movements.
The diagnosis is confirmed with an X-ray of the knee. As some fragments are made up of cartilage, they are more visible on MRI examination.
What can your doctor do?
As long as the bone has not completed its growth, priority is given to relieving the joint: limitation of efforts (sports), use of crutches and wearing a knee brace.
Surgery should only be considered when the condition does not improve after 6 to 12 months. Indeed, this type of intervention can influence the growth of bone.
At the end of growth, the mobile fragment will be reattached in its place.
Small loose pieces can possibly be removed, but the downside is that the joint surface is no longer perfectly smooth, which increases the risk of premature osteoarthritis.
Usually, the beneficial effect of anti-inflammatory drugs (for example, ibuprofen or naproxen) is only temporary: they just reduce the inflammatory symptoms, but do not treat the underlying cause.
Want to know more?
- My child is going to have an X-ray – Plaster
- My child is going to have an MRI – Plaster
- The radiography, here, Where to find on this page of Saint-Luc University Clinics (UCLouvain)
- MRI – Erasme ULB Hospital
- Non-steroidal anti-inflammatory drugs – CBIP – Belgian Center for Pharmacotherapeutic Information
- Ibuprofen – CBIP – Belgian Center for Pharmacotherapeutic Information
- Naproxen – CBIP – Belgian Center for Pharmacotherapeutic Information
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