Adult elbow radiograph (an approach)

Systematic review

Whenever you look at an adult elbow x-ray, review:

• alignment

• fat pads for effusion

• bony cortex

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'tdoes not, think: distal humeral fracture

Check the radiocapitellar line:

• drawn along the radial neck

• should always intersect the capitellum

• if it doesn'tdoes not, 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 in an adult patient, think: acute intra-articular fracture and go looking for it

• if a fracture cannot be identified but an effusion is present, think: undisplaced radial head fracture

Bone cortex

Check around every bone on the film

• look specifically at areas of high-yeild-yield, e.g. radial head and neck and distal humerus

• 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

• mechanism:

  fall on abducted arm; direct blow uncommon

• can be subtle and easily missed

• more...

Elbow dislocation

• up to 25% of all adult elbow injuries; most frequently posterior

• mechanism: fallfall onto extended arm

• associated radial head fracture, coronoid process fracture, or both (‘terrible triad’)

• more...

Distal humeral fracture

• common in elderly osteoporotic patients

• mechanism:

  direct blow or fall on outstretched arm

• typically intra-articular; unicondylar or bicondylar fractures

• more...

Olecranon fracture

• common, represent 10% of all adult upper extremity fractures

• mechanism: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...

Don't miss...

Coronoid process fracture

• uncommon; often in association with dislocation

• mechanism:

  fall onto extended arm

• fragments involving >50% coronoid process are unstable

• check for fractures on post-reduction films

• more...