26th April 2024

A 6-year-old girl presents with a 3-month history of swelling and pain in her right knee.

A 6-year-old girl presents with a 3-month history of swelling and pain in her right knee. Her mother reports that she often complains of stiffness in the knee, especially in the mornings or after naps. The child also appears to be limping slightly. There is no history of injury, fever, or skin rashes. Examination reveals warmth and swelling of the right knee, with a limited range of motion.

Which of the following is the most likely diagnosis?