Discoid meniscus Discoid meniscus This invariably a ff ects the lateral meniscus, which is abnor - mally thick and covers most of the tibial plateau. The child presents with a painful clunk on knee extension. MRI is usually diagnostic. Surgery is indicated for relief of pain or mechanical symptoms. Discoid meniscus This invariably a ff ects the lateral meniscus, which is abnor - mally thick and covers most of the tibial plateau. The child presents with a painful clunk on knee extension. MRI is usually diagnostic. Surgery is indicated for relief of pain or mechanical symptoms. Discoid meniscus This invariably a ff ects the lateral meniscus, which is abnor - mally thick and covers most of the tibial plateau. The child presents with a painful clunk on knee extension. MRI is usually diagnostic. Surgery is indicated for relief of pain or mechanical symptoms.