navicular

Definition

Osteonecrosis of the navicular

Epidemiology

Present at age 4-6 years

- same as Perthes disease

M:F 5:1

Bilateral in 20%

Aetiology

Repetitive trauma to maturing ossific nucleus

Types

1.  Dorsal lip fracture / Tuberosity fracture

- avulsion fractures

- most common

- beware avulsion T post

2.  Body fracture

3.  Stress Fractures

Body Fractures

Types

A.  Transverse fracture in coronal plane

B.  Transverse from dorsolateral to plantarmedial

C.  Central or lateral comminution