CT

Definition

Loss of ligamentous stability between atlas and axis

Can cause impingement of the spinal cord

Etiology

Indications

RA 

OA 

AVN 

Contra-indications

Infection

Charcot

Paralysis of deltoid

Torn rotator cuff

Insufficient glenoid bone stock

Epidemiology

Usually after 50-60 years of age

Aetiology

Primary 90% of cases

Secondary

- AVN

- trauma

- instability

Pathology

Definition

Coronal plane fracture of distal femoral condyle

- intra-articular

- often only attachment is posterior capsule

Epidemiology

Rare

Mechanism

Usually a severe valgus trauma

Xray

Epidemiology

Uncommon

< 1% Primary bone tumour

Young boys

- second decade

Location

Similar to OO

Spine 30%

- especially posterior elements

Long bones 35%

Clinical

Back or limb pain

- pain less severe than OO

Definition

Fracture distal to articular surface & proximal to intertrochanteric region

Epidemiology

On average 4 years younger than intertrochanteric fracture

One year mortality as high as 36%

Only 1/3 will return to pre-fracture living environment

Definition

Bilateral Pars Fracture C2

- traumatic axis spondylolisthesis

NHx

Neurological injury uncommon

- fragments separate and decompress

Different to judicial hanging where spinal cord is severed

Xray

Epidemiology

Rare

- unilateral

- bilateral

Mechanism

Compression

Lateral Compression

Rotation

Clinical

Skull base pain

Cock Robin

Cranial nerve injury

Classification Anderson & Montesano

Type I

Impaction of a condyle 

Definition

Facet joint dislocations secondary flexion distraction injury

Epidemiology

10%

Stages

1. Unifacet subluxation - interspinous process widening

2. Unifacet dislocation - 25% anterolisthesis

3. Bifacet dislocation - 50% anterolisthesis

4. Complete vertebral translation - 100% anterolisthesis

Unilateral Facet Joint Dislocation

Definition

Burst fractures

- injury to anterior and middle columns +/- posterior column

Mechanism

Vertical compression

Epidemiology

10% cervical fractures

Most commonly C5/6

Pathology

Anterior & middle columns fail

- if severe, posterior ligament complex fails