Elbow radiograph (an approach)

Systematic review

Alignment

Check the anterior humeral line:

• drawn down the anterior surface of the humerus
• should intersect the middle 1/3 of the capitellum
• if it doesn't, think distal humeral fracture

Check the radiocapitellar line:

• drawn along the radial neck
• should always intersect the capitellum
• if it doesn't, think radial head dislocation or subluxation
  • check for an accompanying fracture, e.g. Monteggia fracture-dislocation

Effusion

Check for raised fat pads:

• visible posterior fat pad always indicates an elbow effusion
• visible anterior fat pad may be seen in normal patients and should only be thought of as an indicator of an elbow effusion when massively raised
• if there is an effusion, think acute intra-articular fracture
• if a fracture cannot be identified but an effusion is present in an adult patient, think undisplaced radial head fracture

Bone cortex

Check around every bone on the film

• helps to find subtle injuries, e.g. coronoid process fracture or olecranon fracture

Common pathology

Radial head fracture

• commonest adult elbow fracture
• most frequently in women
• fall on abducted arm; direct blow uncommon
• can be subtle and easily missed
• more: radial head fracture

Elbow dislocation

• up to 25% of all adult elbow injuries
• most frequently posterior
• fall onto extended arm
• associated radial head fracture, coronoid process fracture, or both (‘terrible triad’)
• more: elbow dislocation

Distal humeral fracture

• common in elderly osteoporotic patients
• direct blow or fall on outstretched arm
• typically intra-articular (uni- or bi-condylar)
• more: distal humeral fracture

Olecranon fracture

• common, represent 10% of all adult upper extremity fractures
• direct blow, fall on an outstretched hand with flexed elbow, avulsion fracture or stress fracture
• typically widely displaced due to unopposed pull of triceps
• more: olecranon fracture

Don't miss...

Coronoid process fracture

• uncommon; often in association with dislocation
• fall onto extended arm
• fragments involving >50% coronoid process are unstable
• check for fractures on post-reduction films
• more: coronoid process fracture