Fifth Metatarsal Fracture (Tuberosity Avulsion)
Description
This is a break of the fifth metatarsal — the long bone on the outer edge of the foot. The most common type by far, and the focus here, is an avulsion fracture at the base (the tuberosity), where a small flake of bone is pulled off. It heals reliably.
How it happens (the mechanism)
When the foot rolls inward (an inversion injury — the same way an ankle is “sprained”), the peroneus brevis tendon and a band of the foot’s sole that both attach to the base of the fifth metatarsal snap tight and yank a flake of bone off the tip. This is the Zone 1 tuberosity avulsion. Happily, this part of the bone has a rich blood supply, so it heals well — essentially the outer-foot cousin of a pulled-off ankle ligament.
What matters — location is everything
On the fifth metatarsal, exactly where the break sits determines everything. The common tuberosity avulsion (Zone 1) heals quickly and simply. A break a little farther along the bone — the Jones fracture (Zone 2) — sits at a watershed where the blood supply is thin, so it heals more slowly and is treated more cautiously. And in a younger child, a sore, tender bump at this same spot without a true break is often Iselin’s disease, an irritation of the growth center there — not a fracture at all. Telling these apart is the whole game.
Symptoms
Pain, tenderness, swelling, and bruising over the bony base on the outer edge of the foot, often after the foot rolled inward, with difficulty bearing weight.
Doctor examination and imaging
The doctor pinpoints the tenderness at the base of the fifth metatarsal; X-rays show the fracture and, importantly, exactly where along the bone it sits.
Treatment
A tuberosity avulsion is usually treated with a walking boot or a cast for comfort, with weight-bearing as tolerated — it heals well with simple protection. (A Jones fracture, by contrast, is treated more strictly, often with a period of staying off the foot, and in athletes or stubborn cases a small screw is sometimes used to ensure healing.)
Recovery and long-term outlook
The common avulsion heals well and quickly, with full return to activity. Knowing exactly where the break sits is what ensures the right, confident plan.
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) — Toe and Forefoot 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.