In paediatric orthopaedics, growth plate (physeal) injuries are considered "urgent" because these areas of cartilage determine the future length and shape of the bone. These injuries account for about 15% to 30% of all childhood fractures.
1. What is the Growth Plate?
The physis (growth plate) is a specialized area of soft, developing cartilage located near the ends of long bones (like the femur, tibia, and radius).
- The "Weak Link": Because cartilage is softer than bone, the growth plate is actually weaker than the nearby ligaments. An injury that might cause a "sprained ankle" in an adult often results in a "growth plate fracture" in a child.
- Skeletal Maturity: These plates eventually "close" and harden into solid bone, typically around age 14 for girls and 16 for boys.
2. Classification: The Salter-Harris System
Doctors use this system to describe the injury and predict the risk to future growth. A helpful mnemonic is S-A-L-T-R:
3. Signs and Symptoms
Since growth plate injuries happen near joints, they are often mistaken for sprains. Watch for:
- Point Tenderness: Pain exactly over the growth plate when touched.
- Persistent Limp: Inability to bear weight on a leg or use an arm.
- Visible Deformity: The limb appears crooked or bent.
- Swelling and Warmth: Specifically around the joint area.
4. Treatment Options
- Nonsurgical: For "Type I" or "Type II" fractures that aren't displaced, a cast or splint for 3–6 weeks is usually enough.
- Closed Reduction: If the bone is out of place, a doctor may "set" it (move it back) while the child is sedated, without making an incision.
- Surgery (ORIF): For Type III or IV injuries that affect the joint surface, surgeons use screws or pins to hold the growth plate in perfect alignment so it doesn't heal with a "step-off" or a bony bridge.
5. Potential Complications
While most children heal perfectly, the biggest concern is Growth Arrest:
- Bony Bar: A bridge of bone forms across the cartilage, acting like a "staple" that stops growth on one side. This can cause the limb to grow crookedly or stay shorter than the other.
- Follow-up: POSNA recommends monitoring these injuries for at least one year with repeat X-rays to ensure the bone is still growing at the same rate as the uninjured side.
6. Overuse Injuries (Apophysitis)
Not all growth plate injuries are "breaks" from a fall. Repetitive stress from sports can cause inflammation of the growth plate where tendons attach. Common examples include:
- Osgood-Schlatter Disease: Pain at the growth plate just below the kneecap.
- Sever’s Disease: Pain at the growth plate in the heel.