pediatric

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

Issues

1.  More common recently

- more high level sport

2.  High risk of reinjuring knee from instability

- can suffer permanent severe chondral and meniscal damage

3.  Risk of physeal arrest high if bone block across physis

- risk is growth arrest with ACL reconstruction

Epidemiology

Hemarthrosis

- 60% children have ACL tear

Incidence

Very rare

Associated Injuries

SH type 1 femoral epiphysis most common

Management

Closed Reduction

Assess concentric reduction

Assess stability

Apply spica / traction for 2 weeks

Mechanism

FOOSH

- valgus injury

- don't get radial head fracture as is mostly cartilaginous

Types

SH 1 or 2

Associated Injuries

MCL injury

Olecranon / Medial epicondyle fracture

Definition

Fracture / plastic malformation of proximal ulna with dislocation of radial head

Xray

Radio-capitellar line disrupted

Displaced Tibial Shaft Fractures

Acceptable reduction

- varus / valgus < 5^o

- anterior / posterior < 5^o

- rotation 5^o

- shortening 10 mm

Poor remodelling potential

- valgus 

- apex posterior angulation  / recurvatum

- rotational alignment does not remodel

- shortening / in 2-10 year old average overgrowth is only 5mm

Anatomy

Bones more elastic and malleable

- absorb much more energy

Very thick periosteum

- can be periosteal sleeve fracture

Ossification

Triradiate cartilage fuses 13-16

Iliac / Ilium / ASIS apophysis

- appear as teenager

- fuse a couple of years later

- can confuse with fracture

Classification Key & Conwell 1951

Epidemiology

11-18 years

Aetiology

Usually severe trauma

Ossification

Head 5-6 months (1)

GT 2-5 years    (5)

LT 9-13 years  (9)

Delbert Classification

Type 1

Ossification

Distal tibia

- appears by 2 years

- closed at maturity

- asymmetrical closure

- central initially, then posteromedial to anterolateral

- accounts for Tillaux and Triplanar fractures

Distal fibula

- appears by 2 years

- closes 2 years after distal tibia

Medial Malleolar Extension

- begins age 7

- closes age 10