What should you know about juvenile osteochondritis dissecans?

The condition most often affects a weight-bearing joint such as the knee, although other joints can be involved. A child may develop pain or swelling after sport, stiffness, reduced motion, or a feeling that the joint catches. A loose or unstable fragment can interfere with smooth movement and may cause knee locking, which should be assessed rather than pushed through.

An examination helps identify tenderness, movement limits and signs of mechanical catching. Imaging may be used to assess the bone, cartilage and whether a fragment is stable. The age of the child, the joint involved and the appearance of the lesion all influence the plan.

Pause impact activities that reproduce pain and arrange an orthopaedic assessment. Do not return to running, jumping or competitive sport until the treating team has explained what the joint can tolerate. A plan may include activity modification, protected weight-bearing, exercises and physiotherapy to maintain safe strength and movement. Some stable lesions improve with time and careful monitoring; a fragment that remains unstable may require a procedure to protect the joint surface.

Seek prompt care if the child cannot fully straighten the knee, the joint repeatedly locks or gives way, swelling appears suddenly, or pain becomes severe after an injury. Arrange review for persistent activity-related pain, a limp, or reduced movement even when symptoms are mild. A locked joint should not be forced through exercise.

Ask where the lesion is, whether it appears stable, and which activities are safe during healing. Ask what changes would prompt repeat imaging, how physiotherapy will be used, and what signs could mean that cartilage repair surgery should be considered.