Distal Fibula (Ankle) Growth Plate Fracture

Description

This is an injury to the growth plate of the distal fibula — the outer ankle bone. It is one of the most common ankle injuries in growing children, usually from a twist, with tenderness right over the bone.

How it happens (the mechanism)

In a child whose growth plates are still open, the growth plate is often weaker than the nearby ligaments — so the same twist that would sprain an adult’s ankle tends to fracture the growth plate instead (most often the mild Salter-Harris I pattern). That is why tenderness directly over the outer ankle bone in a young child is treated as a fracture even when the X-ray looks normal. The good news is that these bony injuries heal predictably and rarely affect growth.

What matters

A young child with a “sprained ankle” who is tender right on the bone very likely has a growth-plate fracture rather than a ligament sprain — a helpful distinction, because it is treated (and heals) like a fracture, with an excellent outlook.

Symptoms

Pain, swelling, and tenderness over the outer ankle bone after a twist, with difficulty bearing weight.

Doctor examination and imaging

The doctor checks where the tenderness sits — over the bone versus the ligaments; X-rays show the fracture (the mild type may look nearly normal, so the exam guides treatment).

Treatment

Treatment is usually a cast or a walking boot for comfort and protection for a few weeks, with weight-bearing as tolerated. The common mild type typically needs nothing more.

Recovery and long-term outlook

These heal well and rarely cause growth problems, with full return to activity.

When to call the doctor

Call the office right away if your child’s toes become numb, pale, blue, or cold; pain keeps worsening even after raising the leg 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) — Growth Plate Fractures: 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.