Elbow X-ray

Four Questions

Anterior and posterior fat pad signs (in a case of an undisplaced fracture of the radius head which is not visible directly).

A normal anterior fat pad in a non-fractured arm.

Are the fat pads normal?
- A visible ant. fat pad is normal but if displaced anteriorly (Sail sign) it is abnormal
- A visible post. fat pad is always abnormal
- What if have fat pad displacement but no fracture or displacement is identified?
  - Adults: Treat as radial head fracture
  - Peds: Be certain that neither an undisplaced supracondylar fracture nor a displaced internal epicondyle fracture is overlooked!
Is the radiocapitellar line normal?
- A line drawn along the longitudinal axis of the radial head and neck should pass through the capitellum
  - If line does not pass through capitellum then dislocation of radial head is probable
- Whenver there is a fracture of the ulnar shaft must evaluate the radiocapitellar line for possible radial head dislocation (Monteggia fracture dislocation)
- This rule is always valid on a true lateral film
  - In pediatric cases the AP view may be misleading
Is the anterior humeral line normal?
- A line drawn along the ant cortex of the humerus will have at leats 1/3 of the capitellum anterior to it
  - If less than 1/3 then strong probability of supracondylar fracture with distal fragment displaced posteriorly
Are the ossification centers normal?
- CRITOE (Capitellum, Radial head, Internal epicondyle, Trochlea, Olecranon, Lateral Epicondyle)
  - Dislocated elbow may result in avulsion of internal epicondyle
    - Because the trochlea ossifies after the internal epicondyle if you see the trochlea you must find the epicondyle!