A Salter-Harris fracture is a break that runs through or along a growth plate in a child’s bone. Growth plates are thin layers of cartilage near the ends of long bones where new bone forms as a child grows. These injuries account for 15 to 30 percent of all childhood fractures, making them one of the most common bone injuries in kids. They matter because damage to a growth plate can, in some cases, affect how that bone continues to grow.
How Growth Plates Create a Weak Point
In adults, bones are solid from end to end. In children and adolescents, each long bone has at least two growth plates, one near each end. The growth plate sits between two regions: the epiphysis (the rounded end of the bone that forms part of a joint) and the metaphysis (the wider section just below the end). Because growth plate cartilage is softer than the surrounding bone, it’s the most vulnerable part of a child’s skeleton. A force that would cause a sprain or ligament tear in an adult often produces a growth plate fracture in a child instead.
The wrist, ankle, knee, and shoulder are the most commonly affected areas. The growth plate at the far end of the forearm bone (the distal radius) is especially prone to these injuries, typically from a fall on an outstretched hand. Growth plates close gradually during the teenage years, with most fully hardened by age 16 to 18, at which point this type of fracture is no longer possible.
The Five Types of Salter-Harris Fractures
The Salter-Harris classification, introduced in 1963, sorts growth plate fractures into five types based on where the fracture line travels through the bone. The type determines both treatment and the risk of long-term 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 can be hard to see on X-ray because the fracture line sits entirely within cartilage, which doesn’t show up well on standard imaging.
- Type II: The fracture travels along the growth plate and then angles off into the metaphysis, breaking away a small triangular piece of bone. This is the most common type, accounting for roughly 75 percent of all Salter-Harris fractures.
- Type III: The fracture runs along the growth plate and then turns in the opposite direction, splitting through the epiphysis into the joint surface. Because the joint is involved, alignment matters more and surgery is sometimes needed.
- Type IV: The fracture crosses through all three structures: the metaphysis, the growth plate, and the epiphysis. This type carries a higher risk of growth disturbance because the fracture disrupts the full thickness of the plate.
- Type V: A crush injury to the growth plate. There’s no visible fracture line, just compression damage to the cartilage cells responsible for bone growth. Type V injuries are rare, difficult to diagnose at the time of injury, and often only recognized later when a growth problem develops.
A common memory aid uses the word SALTR: Type I is a Slip (or Separation), Type II goes Above the growth plate, Type III goes Lower (through the epiphysis), Type IV goes Through everything, and Type V is a cRush (or Rammed) injury.
How These Fractures Are Diagnosed
Standard X-rays are always the first step. For Types II, III, and IV, X-rays usually show the fracture clearly because the break passes through visible bone. Type I fractures are trickier. The X-ray may look completely normal because the fracture is confined to cartilage, which is invisible on plain film. In these cases, the diagnosis relies heavily on physical exam findings: localized tenderness and swelling directly over the growth plate, especially in a child who fell or twisted a limb.
When X-rays don’t tell the full story, a CT scan is the next step. It provides detailed cross-sectional views that help clarify fracture patterns, particularly when swelling or pain makes it difficult to position the child for ideal X-ray angles. CT is also useful for surgical planning in more complex fractures. MRI can be helpful when the X-ray looks normal but there’s strong clinical suspicion of a fracture. It’s the best tool for visualizing cartilage and soft tissue damage directly, though it’s not routinely used as a first-line test.
Treatment by Fracture Type
Types I and II make up the vast majority of Salter-Harris fractures and generally heal well with conservative treatment. If the bone fragments are out of position, they may need to be gently realigned (a process called reduction, done under sedation or local anesthesia). After that, a cast or splint holds everything in place while healing occurs. For some locations, like the ankle, the cast comes off as early as two weeks. Wrist and other fractures may need three to six weeks of immobilization depending on the child’s age and the specific bone involved. Younger children tend to heal faster.
Types III and IV are more likely to require surgery because the fracture extends into the joint surface. Precise alignment is critical both for normal joint function and to give the growth plate the best chance of recovering. Small pins or screws hold the bone fragments in place during healing. Even with surgery, recovery for most children involves a cast or boot for several weeks afterward, followed by a gradual return to activity.
Type V injuries are rarely diagnosed at the time they happen because there’s nothing visible on initial imaging. Treatment focuses on managing pain and protecting the limb, with close follow-up to monitor growth over the following months and years.
Growth Plate Recovery and Long-Term Outlook
The biggest concern with any Salter-Harris fracture is whether the growth plate will continue working normally after it heals. For Types I and II, the prognosis is generally excellent. The growth plate in most cases resumes normal function, and the bone grows to its expected length. The distal radius (wrist) is especially forgiving. Its growth plate has a simple, linear shape that rarely develops lasting problems even after a fracture.
Types III and IV carry a higher risk of a complication called growth arrest, where part or all of the growth plate stops producing new bone. If only one side of the plate arrests, the bone can grow unevenly, leading to an angular deformity. If the entire plate stops early, the bone on that side ends up shorter than its counterpart. The risk depends on the child’s age (younger children have more growing left to do, so even a small disruption has more time to create a noticeable difference), which bone is involved, and how well the fracture was aligned during treatment.
Growth plates that have a complex, undulating shape, like those around the knee, are more vulnerable to lasting arrest than simpler, flatter plates like the one at the wrist. For this reason, fractures around the knee and ankle tend to get closer monitoring with periodic X-rays over the following one to two years to check for any growth disturbance.
Signs a Growth Plate Fracture Needs Attention
In a child who has fallen or been injured during sports, growth plate fractures don’t always look dramatic. Swelling and tenderness concentrated right at the end of a bone, near a joint, is the hallmark sign. The child will typically refuse to bear weight or use the limb. Because Type I fractures can be invisible on X-ray, a negative X-ray doesn’t always rule out a growth plate injury. If your child has point tenderness over a growth plate after an injury, the standard approach is to treat it as a fracture (with a splint or cast) and reassess in one to two weeks, when healing changes on a follow-up X-ray can confirm the diagnosis.
After a known growth plate fracture has healed, watch for signs that growth may be affected: one limb gradually becoming shorter or curving compared to the other side, or a change in how your child walks or uses the limb. These changes develop slowly over months, which is why follow-up visits are spaced out over a longer period than for a typical broken bone.