A Salter-Harris fracture is a break that runs through or along a growth plate in a child’s bone. Growth plates are bands of cartilage near the ends of long bones that allow bones to lengthen as a child grows. Because these cartilage zones are softer and more vulnerable than the surrounding bone, they’re a common site for fractures in kids and teens. Physeal fractures, as they’re also called, account for 18 to 30% of all pediatric fractures.
The classification system was created in 1963 by two Canadian orthopedic surgeons, Robert B. Salter and W. Robert Harris. It groups growth plate fractures into types based on the path the fracture takes through the bone, which helps predict how the injury will heal and whether it poses a risk to future growth.
Why Growth Plates Are Vulnerable
Most long bones in a child’s body have at least two growth plates, one near each end. Each plate sits between two regions of bone: the epiphysis (the rounded end) and the metaphysis (the flared section just below it). The plate itself is made of a type of cartilage that is structurally weaker than mature bone, which is why forces that would cause a sprain or a simple fracture in an adult often damage the growth plate in a child instead.
Once a child finishes growing, typically in the mid-to-late teen years, these cartilage plates harden into solid bone. At that point, the vulnerability disappears. Until then, any significant force near the end of a long bone can potentially involve the growth plate.
The Five Fracture Types
Salter-Harris fractures are graded from Type I through Type V. The type depends on which structures the fracture line passes through, and higher numbers generally carry a greater risk of growth problems.
- Type I: The fracture runs straight through the growth plate, separating the end of the bone from the shaft. The bone on either side of the plate is undamaged. These fractures can be difficult to see on X-rays because the break is entirely within cartilage, which doesn’t show up well on standard imaging. Swelling and tenderness directly over the growth plate are often the main clues.
- Type II: The fracture goes through the growth plate and then angles off into the metaphysis, breaking away a small wedge of bone on the shaft side. This is the most common type of Salter-Harris fracture. The fragment of bone that chips off makes it easier to spot on X-rays than a Type I.
- Type III: The fracture goes through the growth plate and then turns in the opposite direction, cracking into the epiphysis (the rounded bone end). Because the fracture extends into the joint surface, alignment matters more and surgical repair is sometimes needed.
- Type IV: The fracture crosses all three structures: it passes through the epiphysis, the growth plate, and the metaphysis. This type is more serious because the break disrupts the full thickness of the bone end, and misalignment can directly interfere with how the growth plate functions afterward.
- Type V: Rather than a visible crack, this is a crushing injury to the growth plate itself. It’s the rarest type and the hardest to diagnose initially because X-rays may look normal right after the injury. The damage often only becomes apparent later, when growth slows or stops in the affected area.
A common mnemonic uses the word SALTR: Separated (I), Above (II), Lower (III), Through (IV), Ruined/crushed (V). It’s a quick way to remember which direction each fracture travels relative to the growth plate.
Common Symptoms
A growth plate fracture typically causes pain and swelling near the end of a bone, often around the wrist, ankle, knee, or fingers. Your child may not be able to put weight on the injured limb or move the joint normally. The area directly over the growth plate is usually tender to the touch. In more severe types, the limb may look visibly crooked or deformed.
What makes these fractures tricky is that a Type I fracture can look a lot like a bad sprain. There may be no obvious break on an X-ray. If a child has significant tenderness right at the growth plate after an injury, the fracture may be treated as a growth plate injury even if imaging appears normal. In some cases, an MRI is needed to confirm the diagnosis, since MRI can visualize the cartilage that X-rays miss.
How Growth Plate Fractures Are Treated
Treatment depends on the fracture type and how much the bone fragments have shifted out of position. Types I and II, which make up the majority of cases, are usually managed with a cast. Most kids wear the cast for about four to six weeks while the bone heals. If the bones are displaced, they may need to be realigned (a procedure called reduction) before casting, which is sometimes done under sedation.
Types III and IV more often require surgery to ensure the bone fragments and growth plate are precisely realigned. Pins or screws may be placed to hold everything in position during healing, and a follow-up procedure to remove the hardware is sometimes needed after the bone has mended. Type V injuries, because they involve compression damage to the growth plate itself, are managed based on how the growth plate responds over time rather than with a single upfront fix.
One detail worth knowing: the number of times a fracture needs to be repositioned affects outcomes. Research shows the risk of growth problems is about 11% after a single reduction attempt, but it jumps to 24% after a second attempt and as high as 50% after a third. This is one reason doctors try to get the alignment right the first time.
Growth Complications to Watch For
The main concern with any growth plate fracture is that the injury could disrupt normal bone growth. When the growth plate is damaged, part or all of it can close prematurely, which leads to one of two problems: the bone ends up shorter than it should, or it grows at an angle because one side of the plate stopped working while the other kept going.
Overall, growth arrest occurs in up to 5.5% of all physeal fractures, though the rate varies significantly by fracture type and severity. A prospective study tracking 332 children found radiographic signs of growth disturbance in about 30% of patients on follow-up imaging, though not all of these caused clinically significant problems. Fractures that were initially displaced (shifted out of alignment) carried a higher risk than those that stayed in place, suggesting that how much the bones move at the time of injury matters more than the angle of the break itself.
Higher-type fractures (III, IV, and V) carry more risk because they involve the portion of the growth plate responsible for producing new bone cells. Type V injuries are particularly concerning because the crushing damage may not be recognized early, and growth arrest may only become apparent months later when the bone fails to keep up with the other side.
Recovery and Follow-Up
Most growth plate fractures heal within several weeks, with the typical cast time running four to six weeks for straightforward Type I and II injuries. More severe fractures or those requiring surgery take longer. During recovery, your child will need to avoid sports and physical activities that stress the healing bone. Returning to activity too early increases the chance of re-fracturing the same spot or worsening growth plate damage.
Follow-up appointments are an important part of recovery, sometimes continuing for a year or more. Periodic X-rays allow the doctor to compare growth on the injured side with the uninjured side. This is the only reliable way to catch early signs of growth arrest, which can develop well after the fracture itself has healed. For younger children with many years of growth remaining, monitoring tends to be more frequent and extended, since any growth disturbance has more time to compound into a noticeable difference in limb length or alignment.