Elbow Varus (Gunstock Deformity) After a Childhood Fracture

When a child breaks the elbow just above the joint (a supracondylar fracture) and it heals in a slightly wrong position, the arm can turn inwards at the elbow when straightened. This is called cubitus varus, or "gunstock deformity" because of its shape. It is one of the most common deformities after childhood elbow fractures.

What it looks like

Normally the forearm angles slightly outwards from the upper arm when the elbow is straight (the carrying angle). In cubitus varus this angle is reversed: the forearm points inwards. The elbow may also over-straighten, and the arm may be slightly rotated.

Is it only cosmetic?

Often the main concern is appearance, and many children have good movement. But over the years some patients develop:

• Pain or a sense of instability at the elbow
• Delayed ulnar nerve problems – tingling or weakness in the ring and little fingers
• Snapping of the triceps tendon
• A higher chance of further fractures around the elbow

How we evaluate

1. Comparing both arms: carrying angle, over-straightening, rotation and range of movement
2. Nerve examination, especially the ulnar nerve
3. X-rays of both elbows to measure the deformity
4. Computer-assisted planning of the correction; CT in complex cases

Treatment

The deformity does not correct with growth or exercise. If correction is wanted or needed, it is done by osteotomy of the lower humerus once the fracture has fully healed:

• Lateral closing-wedge osteotomy – a small wedge of bone is removed and fixed with wires, screws or a plate
• Dome or step-cut osteotomies – designed to reduce lateral bony prominence
• Gradual correction with a small external fixator (mini-Ilizarov or hexapod) – useful for larger or combined deformities, allowing fine adjustment after surgery

Correction addresses the inward angle, over-straightening and rotation together where needed.

Recovery

The arm is protected for a few weeks while the bone heals, followed by gentle exercises to regain full movement. Children usually return to school quickly; sports resume once the bone has healed.

Possible complications

Nerve irritation, stiffness, a bony bump on the outer elbow, under- or over-correction, and recurrence in young children. These are discussed in detail before surgery.

Frequently asked questions

When is the best time to correct it? Once the original fracture has completely healed and remodelled – usually at least several months after injury. Timing is individual.

Will my child's arm be weaker? Strength and movement usually remain good after correction with physiotherapy.