A physeal fracture is a break that runs through or involves the growth plate, the thin layer of cartilage near the ends of a child’s long bones where new bone forms and the bone lengthens. Between 15% and 20% of all pediatric fractures involve the growth plate, making these injuries common in children and adolescents. Because the growth plate is softer and more vulnerable than the surrounding bone, it tends to be the weak link during a fall, collision, or other trauma.
Most physeal fractures heal well, typically in just 3 to 4 weeks. But because the growth plate is responsible for how long a bone ultimately becomes, certain types of physeal fractures carry a risk of disrupting normal growth, potentially leading to a shorter limb or a bone that angles in the wrong direction as the child continues to grow.
How the Growth Plate Works
The growth plate (physis) sits between the rounded end of a bone (the epiphysis) and the wider shaft below it (the metaphysis). It’s made entirely of cartilage, and its job is to produce new bone tissue that makes the bone longer over time. Inside the plate, specialized cartilage cells progress through a series of stages: they start in a resting state, then rapidly multiply, enlarge, and eventually die off. As old cells die, they’re replaced by hardite bone. This cycle repeats until the growth plate closes naturally at the end of puberty, at which point the bone has reached its adult length.
The growth plate’s cartilage is structurally weaker than the bone on either side of it. That’s why forces that would cause a ligament sprain in an adult often produce a growth plate fracture in a child instead. Tenderness directly over the growth plate area, rather than over a ligament, is one of the key signs that distinguishes this injury from a simple sprain.
The Salter-Harris Classification
Physeal fractures are categorized using the Salter-Harris system, which describes where the fracture line travels in relation to the growth plate. The type matters because it predicts both how the fracture should be treated and how likely it is to affect future growth.
- Type I: The fracture runs straight through the growth plate, separating the bone end from the shaft. There’s no visible crack through the bone itself on X-ray, which can make it tricky to diagnose. These are sometimes mistaken for sprains.
- Type II: The fracture goes through the growth plate and breaks off a small wedge of the bone shaft. This is the most common type of physeal fracture and generally carries a good prognosis.
- Type III: The fracture runs through the growth plate and down into the bone end, entering the joint. Because the joint surface is involved, this type can damage the smooth cartilage that lines the joint.
- Type IV: The fracture crosses all three zones, passing through the bone end, the growth plate, and the shaft. Like Type III, this involves the joint surface and tends to be more serious.
- Type V: A crush injury that compresses the growth plate. The force damages the cells responsible for producing new bone and can disrupt the blood supply to the plate. Type V fractures are rare but carry the highest risk of growth problems.
A common mnemonic uses the word SALTR: Slipped (I), Above (II), Lower (III), Through (IV), Rammed (V), describing the direction or nature of each fracture line.
What Causes Physeal Fractures
Acute trauma is the most common cause. Falls, sports collisions, and accidents that force a joint beyond its normal range can all crack the growth plate. But a single dramatic event isn’t the only way these injuries happen.
Repetitive stress can also damage the growth plate over time. Children who train intensely in a single sport without adequate rest are especially vulnerable. In young gymnasts, repeated weight-bearing and impact on the wrists can cause a gradual Type I physeal fracture known as “gymnast wrist.” In young baseball pitchers, the repetitive throwing motion places chronic traction on the growth plate at the inner elbow, a condition commonly called “Little Leaguer’s elbow.” On imaging, these overuse injuries show up as widening of the growth plate even when no clear fracture line is visible.
Intense training schedules, year-round focus on a single sport, and a lack of off-season rest all contribute to overuse-related physeal injuries in children.
Which Bones Are Most Affected
Physeal fractures can occur in any bone that still has open growth plates, but in the lower limb, the distal tibia (the lower end of the shinbone near the ankle) is the most frequently affected site, accounting for about 41% of lower-limb physeal fractures. The distal fibula follows close behind at 39%, then the proximal tibia (just below the knee) at 17%, and the distal femur (just above the knee) at about 3%.
The distal femur and proximal tibia are particularly important to monitor after injury because premature growth plate closure occurs most often in these locations, and even a small disruption in these fast-growing plates can produce a noticeable difference in leg length.
Healing and Recovery
One advantage children have is speed of healing. Physeal fractures typically unite in 3 to 4 weeks, faster than standard bone fractures in adults. Most Type I and Type II fractures are treated with a cast or splint after the bone fragments are realigned. If the fracture is already in good position, immobilization alone is usually sufficient.
Type III and IV fractures are more complex. Because they involve the joint surface and cross more of the growth plate’s critical zones, they’re more likely to need surgical realignment to restore the anatomy precisely. The goal is to get the growth plate and joint surface back into their normal positions so the plate can continue functioning and the joint moves smoothly.
For fractures that weren’t displaced, follow-up imaging isn’t always necessary. Parents are typically advised to watch for signs of abnormal growth, like one limb looking shorter or angling differently than the other, and return if anything seems off. For displaced fractures, follow-up continues for at least a year, and sometimes until the child finishes growing, to catch any growth disturbance early.
Growth Complications
The most significant long-term risk from a physeal fracture is premature growth plate closure, where part or all of the growth plate stops producing new bone before it should. This happens when a bridge of bone forms across the injured area, connecting the bone end directly to the shaft and tethering the two together.
Where that bridge forms determines the type of problem it creates. A bridge in the center of the growth plate stops the bone from growing longer, which leads to a limb length difference. A bridge at the edge of the plate allows one side to keep growing while the other side is anchored, causing the bone to angle or curve as the child gets taller. In one documented case, a peripheral bridge in the upper tibia produced a significant angular deformity, with the bone tilting well beyond normal angles.
Type I and II fractures have a low risk of growth arrest because they don’t damage the deepest layer of the growth plate where new cartilage cells are generated. Types III, IV, and V carry a higher risk because the fracture passes through or crushes this critical zone. Type V crush injuries are especially concerning because they can destroy the cells responsible for growth and cut off the plate’s blood supply simultaneously.
When a bone bridge does form and causes problems, the bridge can be surgically removed. After removal, a filler material is placed in the gap to prevent the bone from bridging again. If a significant angular deformity has already developed, a separate procedure to straighten the bone may be needed, since the body’s ability to self-correct these deformities is unpredictable.