Transphyseal Distal Humerus Separation (Infant)

Description

This is a separation through the growth plate of the lower humerus (upper arm bone) at the elbow, in a baby. Because much of an infant’s elbow is still cartilage, it can be hard to see on a plain X-ray and is sometimes mistaken for a dislocation.

How it happens (the mechanism)

In an infant, the lower humerus is largely cartilage, with a wide, relatively weak growth plate. A shearing force — from a birth injury or trauma — separates the bone through that plate. Because so little of the elbow has turned from cartilage into visible bone, the injury is defined more by the relationships between the bones than by an obvious fracture line, which is why it is occasionally missed or confused with a dislocation and why an experienced eye and the right imaging matter.

Symptoms

A swollen, painful elbow in a baby who will not move the arm and is fussy with handling.

Doctor examination and imaging

The doctor evaluates the elbow carefully; ultrasound or additional imaging is sometimes used because the cartilage does not show on plain X-ray.

Treatment

Treatment depends on how much the elbow is shifted: some are gently realigned and held in a splint or cast, others are realigned and held with small pins. Follow-up X-rays confirm alignment as the bones become visible with growth.

Recovery and long-term outlook

Infants have tremendous healing and remodeling ability, so with prompt, accurate treatment the outlook is generally very good.

When to call the doctor

Call the office right away if your child’s fingers become numb, pale, blue, or cold; pain keeps worsening even after raising the arm and giving medicine; swelling does not improve with elevation; the cast feels too tight, cracked, or wet, or smells bad; or your child develops a fever.

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.