mechanism

Vertical Shear

Vertical shear

 

Definition

 

Unstable injuries

Complete disruption of both the anterior and posterior ring

 

5 - 20% of pelvic fractures

 

Mechanism

 

Axial load

Motor vehicle accident

Fall from height

 

Pathology

 

Anterior ring

Cuboid Fractures

Types

 

1.  Capsular avulsions

 

2.  Body / Nutcracker fracture

 

Nutcracker fracture

 

Epidemiology

- rare

 

Mechanism

- forced eversion / abduction of forefoot

- cuboid crushed between 4th and 5th MT and calaneum

 

Pathology

- displaced cuboid fracture with subluxation of tarsus

Hoffa fracture

Definition

Hoffa Fracture Xray

 

Coronal plane fracture of distal femoral condyle

- intra-articular

- often only attachment is posterior capsule

 

Epidemiology

 

Rare

 

Mechanism

 

Usually a severe valgus trauma

 

Xray

 

Central Cord Syndrome

Epidemiology

 

Most common pattern cord injury

 

Hyper-extension injury in middle aged man with osteoarthritic spine

 

Usually C3/4 and C4/5

 

Mechanism

 

Most common type / in older patient with pre-existing spondylosis / OPLL

- hyperextension injury

- compression of the cord

- anteriorly by osteophytes

- posteriorly by infolded ligamentum flavum

 

Facet Joint Dislocation

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

 

DIC

Definition

 

Disseminated Intravascular Coagulation

 

Pathology

 

Results from excessive activation of either extrinsic or intrinsic coagulation pathway

- multiple small clots 

- consumptive coagulopathy

 

1.  Excessive Extrinsic Activation

 

Secondary to extensive cellular destruction

- thromboplastins +++ released into circulation

Sacral Fractures

Mechanism

 

High energy usually

 

Occasionally osteoporotic fracture in elderly

 

Other

- radiotherapy

- fatigue fracture in children

 

Don't present as isolated injury

- associated with pelvic fracture

 

Denis Classification

 

Zone 1

- lateral to foramina

- neurologic injury from proximal migration & compression of L5 nerve root

Spinal Cord Concussion

Definition

 

Transient disturbance of spinal cord function

- +/- vertebral column injury

- no pathological changes in spinal cord

 

Mechanism

 

Rapid change in velocity following trauma

- football / ice hockey

 

Associations

 

Congenitally narrow spinal cord

Hypermobility