site

Background

Osteochondritis Dissecans

- separation of avascular fragment of bone & cartilage

M : F = 2:1

Mean age 18 years

- can present as young as 9

4:1000

Rare low-grade malignant tumour

- cell of origin unknown

Usually second or third decade of life

90% diaphysis of tibia

Mandible

Most common anterior cortex of tibia

Definition

Infection of bone 2° blood-borne bacteria

Most common children

- peak 10 years

True haematogenous OM rare in adults

- usually involves spine

M: F 2:1

Most common femur & tibia