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