CT

Incidence

Dale et al Acta Orthop 2012

- Nordic Arthroplasty Registry of 430,000 THA

Definition

Ossification of the posterior longitudinal ligament (OPLL)

Heterotopic ossification of the posterior longitudinal ligament

Epidemiology

2:1 Male:Female

More common in Japanese and East Asian populations

 Articular process fracture

Natural history

Superior articular process fracture

- potentially unstable

Inferior articular process fracture

- thought to be more stable

CT scan

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

Femoral Neck Stress Fractures

Aetiology

Athletes with increase activity / distance

Women with eating disorders /  amenorrhea

Types

Compression / inferior neck

- < 50% protective weight bear

- > 50% emergent ORIF

Tension side / superior neck

- emergent ORIF

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