SUPRACONDYLAR FRACTURE
(KIDS BROKEN ELBOW)
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related topics: broken arm, broken wrist, broken radial head, broken medial epicondyle, broken lateral condyle, broken forearm
What is a Supracondylar Fracture (Pediatric Broken Elbow)?
Supracondylar fractures are a very common type of broken elbow seen in kids, especially ages 3-8 years old. They occur after a fall onto an outstretched arm, and they usually by falling off the monkeybars.
The injury occurs in a part of the arm bone (aka the humerus) just above the elbow joint. The name Supracondylar Fracture refers to this location: "supra" (above), "condylar" (aka condyles, which are the two bumps you can feel on either side of your elbow). In this area, the arm bone becomes thin (it appears as an hour-glass shape) to give our elbow a good range of motion. But because the bone is thin, its a weak spot that can crack when the elbow is bent backward ("hyper-extended").
Hyper-extension of the elbow causes an Extension Type supracondylar fracture (seen in 95% of cases). The Extension Type occurs when a child completely straightens their arm to brace for a fall, which sounds normal enough, and in most cases nothing happens. But in rare cases when there is too much force with the fall (like seen when falling off the monkeybars), our muscles that bend the elbow (called the biceps and brachialis) cannot absorb this big force so all the energy gets transmitted directly to the arm bone. The pointy part of the elbow (called the olecranon, yes its a silly name) acts as a fulcrum and the humerus cracks over it. Ouch.
A Flexion Type Supracondylar Fracture, where the elbow is hyper-bent forward, can occur but is only seen in 5% of cases.
Now that we know where this injury occurs, lets see how its diagnosed.
Diagnosing a Supracondylar Fracture (Pediatric Broken Elbow)?
The diagnosis of a Supracondylar Fracture is made by first listening to the history of a child's injury and their symptoms. Most of these injuries occur after falling from a height (like falling off the bed, off the monkeybars, or off somewhere else a few feet off from the ground). Kids will immediately report pain, swelling and inability to straighten the elbow.
Based on this type of story doctors will be suspicious for this injury and will order X-rays of the elbow and forearm to diagnose the fracture.
A Supracondylar fracture is best seen on a side view (because in a supracondylar fracture the arm bone bends backward). Based on the severity of the break the injury is classified as a Gartland Type 1, 2, or 3. A Type 1 fracture is nondisplaced: the bone is broken, but the fragment didnt move out of position. A Type 2 is bent backward, but part of the bone remains in contact (think of the bone as being hinged open). A Type 3 is bent really far backward and none of the bone remains in contact (its completely displaced). This classification system helps to guide treatment.
A front view x-ray is also important to see if the broken bone has rotated, or if it has become squished on one side. If one of these patterns is seen, it is an indication of a more severe injury.
Its important to not only get x-rays to diagnose the break, but to also examine the arm to see if any muscle, artery or nerve was also damaged.
This is of particular concern for Type 3 injuries when the broken bone has moved significantly out of position. The most commonly injured muscle is the brachialis (which can get caught by a spike of bone). The most commonly injured nerve is the AIN (which is a branch of the Median nerve), and the most commonly injured artery is the Brachial Artery (which travels along side the median nerve). Injury to any of these tissues is important to identify because it means the timeline for treatment needs to move quickly so that everything will heal.
Lastly, its important to check the whole arm for signs of additional breaks. About 10% of children with a supracondylar fracture will also have a broken wrist that requires treatment.
Treating a Supracondylar Fracture (Pediatric Broken Elbow)?
Treatment depends on the severity of the injury, but regardless of the required treatment, all kids are expected to be able to resume all of their normal activities (only sometimes it takes a bit more work to get the bone to heal).
To ensure normal elbow function, the arm needs to be straight. Looking at the side view of the elbow on x-ray, the bone alignment is measured by drawing a line along the front of the humerus and seeing if it intersects the capitellum, see picture).
Treatment is based on the Gartland Classification.
Type 1 injuries heal without problems and they are placed into a long-arm cast for about 3 weeks, then regular activities gradually resume.
Type 2 injuries are sometimes treated in a long-arm cast, but these oftentimes require surgery. Sometimes a doctor can gently push on the elbow to realign the elbow and then put the arm in a cast. However, its not uncommon for the broken elbow to be too unstable, and the break re-separates within the cast. To prevent this re-separation, two or three pins can be placed to hold the break together while it heals.
Doctors try to look for clues on x-ray to determine which of the Type 2 injuries will do well in a cast, and which need pins. The more severely broken fragment (measured by the humeral-capitellar angle), and the degree of medial sided bone collapse (called Baumanns angle) are risk factors for re-separation and encourage pin fixation.
All Type 3 fractures require pins to hold the fracture in place because the broken piece is too unstable. The pins get removed at 3 weeks (they can be pulled out in the office, this only hurts a little) and then the arm stays in a cast for more 3 weeks to ensure the bone heals completely.
What is the long term outcome?
Type 1 injuries heal very well in a cast. Type 2 injuries treated in a cast often require surgery due to re-separation of the break and elbow malalignment. Studies suggest about 20-30% of kids initially casted end up needing surgery (and sometimes the surgery more complicated than two small pins). When these injuries are treated right away with pins the outcome is very good. There is a low risk of complications (like an infection around the pin, or injury to any nerves) and the elbow alignment very reliably corrected. This has lead the American Academy of Orthopedic Surgeons to establish guidelines that generally recommend pinning of Type 2 injuries because of the low risk, and high reward.
Type 3 injuries are treated expediently with pins to minimize severe swelling (which can lead to compartment syndrome, see talk). Additionally, nerve or artery injury sometimes caused by these severe breaks requires urgent treatment to maximize the chance of full recovery (which is seen in the majority of cases). Like Type 2 injuries, kids heal very well when the injury is treated with pinning.
Pinning the prevents malalignment of the elbow. Malalignment occurs in hyperextension, which prevents full elbow range of motion. Also malalignment can occur if there is medial column collapse causing the elbow bend inward (cubitus varus) which causes an aesthetic problem (it can almost looks like you have two left arms). This is called a Gunstock Deformity.
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References
1) American Academy of Orthopedic Surgeons. The Treatment of Pediatric Supracondylar Humerus Fractures. Evidence-based Guideline and Evidence Report. 2011. full report.
2) Abzug JM. Management of supracondylar humerus fractures in children: Current Concepts of Treatment. JAAOS 2012; 20: 69-77. full article.
3) Parikh SN et al. Displaced type II extension supracondylar humerus fractures: Do they all need pinning? JPO 2004; 24: 80-4. full article.
4) Walmsley PJ et al. Delay increases the need for open reduction of type-III supracondylar fractures of the humerus. JBJS Br 2006; 88: 528-530. full article.
5) O'Hara LJ et a. Displaced supracondylar fractures of the humerus in children: Aduit changes practice. JBJS BR 2000; 82: 204-210. full article.
6) Omid R et al. Supracondylar humeral fractures in children. JBJS 2008; 90:1121-32. full article.