Supracondylar Humerus Fracture (Elbow)

Description

The humerus is the upper arm bone, running from the shoulder to the elbow. Just above the elbow, the bone flares and thins into two pillars — the medial column (inner) and the lateral column (outer) — with a thin section between them. This area is called the supracondylar region, and a break here is a supracondylar humerus fracture. It is the most common elbow fracture in young children.

It happens most often between about ages 3 and 8 (with a peak around 5 to 7), almost always from a fall onto an outstretched hand with the elbow straight — for example, off the monkey bars, a bed, or while running and tripping.

How it happens (the mechanism)

There is a reason this fracture clusters in this age group. At the back of the lower humerus is a small hollow called the olecranon fossa — the notch that the elbow’s hinge swings into when the arm straightens. During these years of growth, the bone at the floor of this fossa is naturally very thin, almost eggshell-thin.

When a child falls onto an outstretched hand with the elbow extended, the pointed tip of the forearm bone (the olecranon, the hook-shaped “point” of the elbow) is driven hard into that thin fossa. This creates a straight-across (transverse) crack that then travels outward through the medial and lateral columns — producing the supracondylar fracture.

A point that parents very often ask about: this is not a growth plate injury. The break sits just above the elbow’s growth plates, so the growth plates themselves are not damaged and your child’s growth is not expected to be affected.

Why good alignment matters

Not all growth plates are equally powerful, and that fact shapes how this fracture is treated. The growth plate near the shoulder, at the top of the humerus, is extremely active — about 80% of the arm bone’s growth comes from there. A bone with such a powerful growth plate heals quickly and can also remodel quickly, straightening out many minor angles and shifts on its own over time.

The growth plates at the elbow end, by contrast, have very little remodeling power. So a supracondylar fracture cannot be counted on to straighten itself — it needs to heal in good alignment from the start. If it heals crooked (a malunion), the result is most often a cosmetic difference in the elbow’s shape, but a more significant malunion can limit how fully the elbow bends and straightens and, rarely, contribute to nerve irritation years later. Correcting a malunion after it has healed requires a second, more demanding operation. This is why the priority is to get the alignment right early and, when needed, to hold it with pins.

Types of supracondylar fractures

It helps to picture a sleeve of tissue called the periosteum that wraps the bone like a tough layer of plastic wrap. When a fracture has not moved, this sleeve is usually intact and holds the bone steady; when the bone shifts, it tells us the sleeve has torn on one side. Surgeons use this, with the X-ray, to grade the fracture:

• Type 1 — nondisplaced: a crack that has not moved or tilted; the periosteal sleeve is intact and the fracture is stable.
• Type 2 — angulated: the bone is tilted (usually backward) but still connected on one side, where the intact periosteum acts as a hinge.
• Type 3 — displaced: the bone is broken all the way through and shifted, the most unstable common pattern; usually the periosteum on one side (often the back) is still intact and can be used as a hinge to guide the bone back.
• Type 4 — unstable in both directions: unstable whether the elbow is bent or straight; this type is identified during surgery.

Symptoms

• Pain and swelling around the elbow, often with bruising
• Refusing to move or use the arm, holding it close to the body
• A crooked or deformed look to the elbow in more displaced breaks
• Numbness, tingling, or weakness in the hand, which should be checked promptly

Doctor examination and imaging

Because nerves and a major blood vessel pass directly across this fracture, the doctor carefully checks the movement, feeling, and circulation of the hand and fingers — including the wrist pulse and tests like making an “OK” sign and a “thumbs up.” X-rays from the front and side confirm the fracture and how far it has moved.

Nonsurgical treatment

A Type 1 (nondisplaced) fracture is treated in a long-arm cast for about three to four weeks, watched closely with an X-ray when the cast comes off. Some mildly angulated Type 2 fractures may be realigned and casted without pins, but this calls for very close follow-up (often a weekly X-ray), because there is a higher chance the bone tilts again; if it shifts, the plan may change to pinning.

Surgical treatment

Displaced fractures are usually realigned and held with smooth metal pins. While the child is asleep under anesthesia, the surgeon guides the bone back into position — often using the intact periosteum as a hinge — and places two to four pins through the skin (closed reduction and percutaneous pinning), then applies a cast.

Occasionally a small incision (open reduction) is needed — if good alignment cannot be achieved closed, if soft tissue such as a muscle, nerve, or blood vessel is caught in the fracture, or if it is too unstable. The bone is still secured with pins, and the small incision is closed.

Nerve and blood vessel concerns

Because nerves and a blood vessel run right in front of the fossa, they can be stretched when the bone displaces — mainly in Type 3 and 4 fractures, and rarely in Type 1 and 2. When a nerve is affected, it is most often the anterior interosseous nerve (AIN), a branch of the median nerve that lets a child bend the tip of the thumb and index finger into an “OK” sign; sometimes it is the radial nerve (“thumbs up”). These are almost always stretch injuries (a neuropraxia) that recover on their own, so they are simply observed with reassurance for about three months, with further testing only in the uncommon case that function has not begun to return. Serious blood-vessel injury is uncommon and is associated with severe displaced fractures, which is why those are evaluated very carefully before and after surgery.

Recovery and long-term outlook

Most children are in a cast for three to six weeks. When pins are used, they are removed in the clinic at around three to four weeks — without anesthesia, because removal causes only brief, minimal discomfort; there is often a little bleeding for a minute or two that a small bandage handles. After the cast comes off, the elbow regains motion over several weeks to a few months, and the large majority of children recover full or nearly full function.

When to call the doctor

Call right away or seek emergency care if pain becomes severe or out of proportion — especially pain when the fingers are gently straightened — or the fingers become numb, pale, blue, or cold, or the cast feels dangerously tight. These can signal dangerous pressure within the arm (compartment syndrome). Also call for fever, worsening swelling, or drainage.

Common questions

• Is my child’s growth affected? No — the fracture is above the growth plates.
• Does pin removal hurt? Very little; it is quick and done in clinic without anesthesia.
• Will the elbow look and work normally? In the great majority of children, yes; a small number have a slight, usually cosmetic change in the elbow’s shape.
• When can my child return to play? Generally after the fracture has healed and motion and strength are returning; your surgeon will give a timeline.

Learn more

OrthoInfo (AAOS) — Elbow Fractures in Children: orthoinfo.aaos.org

This information is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. For specific concerns about your child, consult a board-certified, fellowship-trained pediatric orthopaedic surgeon.