An area of the surface of the knee loses its blood supply and cartilage +/- bone can fragment off

Aetiology

• Most common in adolescence

Clinical features

• Knee pain after exercise
• Intermittent swelling and locking

Investigations

• Imaging:
  • X-ray, MRI

Management

• Can heal or resolve spontaneously
• Indications for surgery controversial
  • If detaching on MRI can pin in place
  • If detached can fix or remove
  • May consider cartilage regeneration for persistent pain
• Needs specialist referral