disease

Definition

Calcaneal apophysitis 

- overuse injury

- stress fracture in secondary growth center of calcaneum

Epidemiology

4/1000

Boys > girls

10 - 12

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

Definition 

Avascular necrosis & subsequent disintegration of lunate

Aetiology

50-75% history of trauma

Occasionally seen in sickle cell / steroid use

Pathogenesis

Vascular Theory

Trauma disrupting vascularity

- single incident with disruption of blood supply