System for Reading Pediatric Elbow Xrays
Verify patient name and side
Quality of views
Follow cortices and medullary canals proximal to distal humerus, ulna, then radius
Anterior humeral line
Radiocapitellar line
Assess joint line for varus valgus
Assess Physes
Soft tissue shadows
Look closely at point of maximal tenderness (based off your physical exam)
Assessing quality of elbow xrays:
The true lateral elbow has a minimal AP dimension.
Semi-circular surfaces of condyles aligned.
Space visible across ulnohumeral joint
Anterior humeral line:
Should cross middle third of capitellum, if it doesn’t the lateral view is off or that a fracture is likely
Radiocapitellar line (aka. Proximal radial line)
Line should bisect the capitellum into halves (if it doesn’t that means radial head dislocation)
The proximal radial line should always bisect the capitellum in any projection
Varus valgus of elbow:
Varus means the distal segment is going towards midline
Valgus means the distal segment is going away from midline
The above picture shows the carrying angle (Cubitus angle)
If it is inferior to 5 degrees : Cubitus varus
And when it is superior to 15 degrees: Cubitus valgus
Physes in pediatric elbow:
Ossification center (bone is added to cartilage scaffold) – CRITOE is an important acronym | Age at ossification (appears on xrays) – goes up by odd numbers, +/- 1 year between boys/girls |
Capitellum | 1 |
Radius | 3 |
Internal (medial) epicondyle | 5 |
Trochlea | 7 |
Olecranon | 9 |
External (lateral) epicondyle | 11 |
Soft tissue shadows:
Fat pad sign does not equal fracture, it indicates increased chance of fracture
Anterior fat pad: Probability is 70-80% for intra-articular fracture
Posterior fat pad: Probability is 90% for intra-articular fracture
Example Case
Image reference: Twitter @davembmd
Practice with the image above! Check the comments for the answer!
Does anyone know what the image is showing?
References:
http://www.wikiradiography.net/page/The+Paediatric+Elbow
https://radiopaedia.org/cases/normal-elbow-carrying-angle
https://www.orthobullets.com/pediatrics/4008/medial-epicondylar-fractures–pediatric
Dislocated radial head