Paediatric Supracondylar Fractures – A Medical Student Clinical Pearl
Reviewed by Dr. Joanna Middleton
Copyedited by Dr. Mandy Peach
Christine Crain (She/Her), CC3
Dalhousie Medicine MD Candidate, Class of 2022
Relevant Case:
On a Saturday, a three-year-old presented to the emergency department with his mother. He’d been playing in the backyard with his older sister who was on their swing. Unfortunately, the boy walked in front of the swing and was hit by his sister. He fell onto an outstretched hand and immediately began to cry and hold his elbow.
Problem:
There are two kinds of Supracondylar fracture; extension, which accounts for up to 95% of these fractures; and the far less common flexion fracture which occurs almost exclusively in older adults.
When a paediatric patient falls into an outstretched hand, the olecranon engages with the fossa, then acts as a fulcrum hyperextending the elbow, punching the olecranon through the relatively thin and weak supracondylar region of the humerus.
Figure 1: Case courtesy of Dr Samir Benoudina, Radiopaedia.org, rID: 39938
The Gartland classification (Fig.1) of supracondylar humeral fractures are based on the degree and direction of any displacement where Type 1 fractures imply little (1b) to no displacement (1a). Type 2 fractures displace the anterior humeral line (Fig.2) but leaves the posterior cortex intact; while type 3 fractures are completely displaced.
Figure 2: The anterior humeral line should pass through the middle third of the humeral capitulum. Case courtesy of Dr Samir Benoudina, Radiopaedia.org, rID: 41167.
Since these fractures commonly occur in children, learners especially need to be aware of the ossification centers within the elbow to be certain that they’re recognized as normal anatomy and not additional fractures. The age of the child should help you to estimate, with the help of a handy mnemonic, which ossifications centers should be visible on radiograph:
Figure 3: Case courtesy of Leonardo Lustosa, Radiopaedia.org, rID: 80555
In our case, with a three-year-old male, we would expect to see the Capitellum and Radial Head, but no other centers. We know any “fragments” in these areas are not additional fractures.
Most commonly in supracondylar fractures, there are other signs we look for that may indicate injury to the cartilage and forming bone:
- Sail Sign shows a joint effusion under the Anterior fat pad (Fig. 4)
- Posterior Fat Pad sign is the same, only on the posterior aspect of the elbow (Fig. 4)
- And, as noted above, the Anterior Humeral Line should intersect the middle third of the Capitellum (Fig. 2)
Figure 4: Showing both Anterior and Posterior fat pad sign. Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 13527
Finally, given the number of vascular/neural structures that pass through the elbow, what complications are there to be aware of? As with all fractures, there is a risk of non/malunion, this is a relatively low risk however and is beyond the scope of this pearl.
Vascular complications include Volkmann’s contracture which can occur with injury to the brachial artery. This can result in a volar compartment syndrome leading to fibrosis and contracture of flexor muscles.
Finally, injury to any of the nerves that travel to innervate the hand/forearm can occur. Innervation through the Radial, Median (as well as the Anterior Interosseous nerve), and Ulnar nerves can be verified by a few quick and easy maneuvers as seen in Figure 5.
Figure 5: Innervation of the hand for the purposes of nerve injury screening.
Case Resolutions:
Inspection prior to radiographs showed intact sensation, brisk capillary refill with strong distal pulses, and ongoing ability to move joints below the injury. He was sent for radiographs which reported a supracondylar fracture. We casted his elbow and sent him for follow up to the Ortho fracture clinic the following week.
Conclusion
While learners may initially think ossification centers of the elbow are fracture fragments, using CRITOE they will be able to rule out joint involvement. This will allow you to move more quickly onto other radiographic signs of fracture.
References
- https://radiopaedia.org/articles/supracondylar-humeral-fracture-2
- https://radiopaedia.org/articles/gartland-classification-of-supracondylar-humeral-fractures
- https://radiopaedia.org/articles/anterior-humeral-line
- https://radiopaedia.org/articles/elbow-ossification-mnemonic
- https://radiopaedia.org/articles/sail-sign-elbow-1
- https://www.orthobullets.com/pediatrics/4007/supracondylar-fracture–pediatric