Welcome back to another Clinical Image of the Week from the case files of the Brown EM Residency!
HPI: 6 year old male presents to the ED after falling about 4 feet off the monkey bars at his school playground, landing on his right arm. He’s had worsening pain and swelling of the right elbow since the fall, resulting in limited range of motion. He denies numbness, tingling, or weakness. He sustained no other injuries.
Vitals: BP 107/72, HR 105, T 98.7 °F, RR 22, SpO2 100 % on RA
Notable PE: There is mild swelling of the right elbow, with limited active range of motion, but intact passive range of motion. No obvious deformity. He is tender in the lateral supracondylar region. His right upper extremity is neurovascularly intact.
Plain films were obtained:
What’s the diagnosis?
Radial Head Dislocation
Here are some quick facts:
- Typically seen in infancy and childhood, versus adulthood.
- Children will typically not want to use the involved extremity due to pain or swelling.
- Important to ensure that the dislocation is truly isolated, as less commonly there can also be bowing or fracture of the ulna (Monteggia fracture) .
- It is also important to distinguish this from a subluxation injury (Nursemaid’s elbow).
- Most of the time, the radial head dislocates anteriorly, which can be appreciated by disruption of the radiocapitellar line, in which a line extending through the neck of the radial head should normally intersect the capitellum.
- Note the patient’s post-reduction films, as compared to prior. The radiocapitellar line is in red:
- C: Capitellum (1 year)
- R: Radial head (3 years)
- I: Internal epicondyle (5 years)
- T: Trochlea (7 years)
- O: Olecranon (9 years)
- E: External epicondyle (11 years)
- Patient underwent a successful closed reduction under sedation (as seen above), and was placed in a posterior splint. He followed up with orthopedics.
For a great review on this:
Shout out to Dr. Merritt for this case!
The contents of this case were deliberately altered to protect the identity of the patient. All content in this report are for educational purposes only. The patient consented to the use of these images.
See you next week!
Source: Gaillard, Frank, Knipe, Henry, et al. Radial Head Dislocation. Radiopedia. 2015. <http://radiopaedia.org/articles/radial-head-dislocation>.