What is it?
A local area of bone beneath cartilage is affected; the overlying cartilage fragment can become unstable.
Symptoms and important signs
Activity pain, swelling or catching and locking.
How is it assessed?
X-ray and selected MRI assess size and stability; skeletal maturity matters.
Care and treatment options
Stable lesions may need load restriction and follow-up; unstable fragments may need surgery.
When to seek help
True locking or progressive loss of movement needs early assessment.