A Salter-Harris fracture is a break that runs through or involves the growth plate, the layer of cartilage near the ends of children’s bones that allows those bones to lengthen. Because growth plates are softer and more vulnerable than the surrounding bone, they are a weak point in the developing skeleton, and these fractures account for a significant share of childhood bone injuries. The classification system, first described in 1963, divides these injuries into five types based on the fracture line’s path through the bone, and that distinction matters because it directly shapes treatment decisions and the risk of long-term growth problems.
The Five Types and What They Mean
The Salter-Harris system groups growth plate fractures by how the break travels through three zones: the growth plate itself (the physis), the rounded end of the bone (the epiphysis), and the wider shaft-side portion just below the growth plate (the metaphysis). Each type carries different implications for healing and for the chance that normal bone growth will be disrupted afterward.
- Type I: The fracture separates the growth plate horizontally without cracking into the bone on either side. These can be subtle on X-rays because no bone fragment is visibly displaced.
- Type II: The fracture runs through the growth plate and angles off into the metaphysis, leaving a triangular chip of bone attached to the separated piece. This is by far the most common pattern, making up roughly three-quarters of all growth plate fractures.
- Type III: The fracture crosses through the growth plate and then splits into the epiphysis, extending into the joint surface. Because the joint is involved, alignment matters more.
- Type IV: The fracture line cuts across all three zones, running from the metaphysis through the growth plate and into the epiphysis. This also disrupts the joint surface and often requires surgery.
- Type V: A crush injury that compresses the growth plate without producing an obvious fracture fragment. These are rare and notoriously difficult to identify at the time of injury.
A helpful mnemonic some clinicians use maps the five types to the word SALTR: Slipped (Type I), Above (Type II, metaphysis), Lower (Type III, epiphysis), Through (Type IV, all layers), and Rammed/crushed (Type V).
Who Gets These Fractures, and Where
Growth plate fractures are a pediatric problem by definition: once the growth plates fuse during late adolescence, this injury type is no longer possible. Boys are affected about twice as often as girls, partly because growth plates fuse later in boys, leaving a longer window of vulnerability. In a study of more than 1,100 children with growth plate fractures, the peak number of injuries occurred during adolescence, and boys outnumbered girls by more than two to one.
The most common location is the wrist. The distal radius alone accounted for roughly 40% of fractures in that same cohort, followed by the finger bones and the elbow region around the distal humerus.1PubMed Central. Clinical characteristics of 1124 children with epiphyseal fractures The wrist dominance makes intuitive sense: kids fall onto outstretched hands constantly. Type II fractures dominated at nearly every location, with the wrist seeing 454 out of 460 cases classified as Type II.2PubMed Central. Clinical characteristics of 1124 children with epiphyseal fractures
Falls and sports collisions are the usual culprits, but overuse injuries deserve separate attention. Repetitive stress on growing bones, such as the wrist loading seen in young gymnasts or the shoulder strain from overhead throwing in youth baseball, can damage the growth plate without a single dramatic impact. These chronic injuries have become more common as youth sports have grown more competitive and year-round.3PubMed Central. Overuse Physeal Injuries in Youth Athletes Risk Factors, Prevention, and Treatment Strategies The concern is not just the immediate fracture but the cumulative wear on a structure that cannot regenerate indefinitely.
Why X-Rays Sometimes Miss the Fracture
Standard X-rays are the first step in diagnosis, and they reliably pick up Type II and Type IV fractures because a visible bone fragment has shifted out of place. Type I and Type V injuries are a different story. Since the fracture line runs through cartilage that does not show up well on plain films, the X-ray can look normal even when the growth plate is genuinely injured. A child with point tenderness directly over the growth plate and a convincing story of injury is often treated as if a fracture is present, even when the X-ray is negative.
MRI has proven valuable in these ambiguous cases. In one study of children and adolescents whose initial X-rays were negative, MRI detected occult fractures about 35% of the time.4PubMed. MRI for occult physeal fracture detection in children and adolescents That is a substantial miss rate for plain films alone. MRI’s ability to visualize cartilage directly also changed the Salter-Harris classification in some patients and led to a change in management in about a third of cases studied.5PubMed. MRI of pediatric growth plate injury: correlation with plain film radiographs and clinical outcome
For fractures that involve the joint surface, particularly Type III injuries, plain X-rays also tend to underestimate how far the bone fragments have shifted. One study found that X-rays measured an average displacement of less than half a millimeter in cases where MRI or CT showed the fragments were actually displaced by closer to 3 millimeters.6Journal of Pediatric Orthopaedics. Salter-Harris Type III Fractures of the Distal Femur That gap can make the difference between casting and surgery.
Treatment for Type I and Type II Fractures
The good news is that the most common growth plate fractures, Types I and II, generally heal well with non-surgical treatment. The standard approach is to realign the bone if it has shifted (a procedure called reduction, usually done under anesthesia) and then immobilize the limb in a cast. Healing typically takes about 30 to 45 days depending on the child’s age, and joint mobility afterward returns to normal in the vast majority of cases.7PubMed Central. The therapeutic attitude in distal radial Salter and Harris type I and II fractures in children
Casting technique matters more than you might expect. For distal radius fractures, the position of the wrist in the cast affects whether the bone stays aligned during healing. Research has shown that a modest degree of wrist flexion in the cast reliably prevents re-displacement, which reduces the need for repeat procedures.8PubMed. Flexed position of the wrist in the cast reliably prevents displacement after physeal Salter-Harris I and II distal radius fractures This is one of those details that sounds minor but can spare a child a second trip to the operating room.
Follow-up imaging is important even when the initial treatment goes smoothly. Because growth disturbance can develop silently over months, most orthopedic surgeons schedule X-rays at intervals after the cast comes off to check that the bone is continuing to grow normally.
When Surgery Is Needed
Type III and Type IV fractures involve the joint surface and usually require surgical fixation to restore alignment. The joint must be reconstructed accurately to prevent arthritis later, and the growth plate fragments need to be held in their correct positions to give the plate the best chance of continuing to function. In one series of Type III and IV fractures of the proximal tibia (just below the knee), every single patient also had damage to a meniscus, ligament, or blood vessel, underscoring how these higher-grade injuries tend to involve more than just the bone. Despite that complexity, surgical fixation produced good functional outcomes and all fractures healed.9Journal of Pediatric Orthopaedics B. Clinical and functional outcomes after operative management of Salter–Harris III and IV fractures of the proximal tibial epiphysis
The hardware used during surgery raises a practical concern unique to children: screws or plates that cross the growth plate can themselves cause growth problems. Surgeons try to avoid crossing the plate when possible, or they use smooth pins that are less likely to tether the growing cartilage. In some cases, provisional external fixation and specialized plating that spans the open growth plate are used to provide stability while minimizing damage.10Journal of Pediatric Orthopaedics B. Clinical and functional outcomes after operative management of Salter–Harris III and IV fractures of the proximal tibial epiphysis
What Determines Whether Growth Gets Disrupted
The question every parent asks is whether the fracture will affect their child’s growth. The honest answer is that most growth plate fractures heal without lasting problems, but the risk is not zero, and certain factors push it higher.
Fracture location is one of the strongest predictors. In a prospective study tracking hundreds of children with growth plate fractures, the distal femur (just above the knee) had the highest rate of growth arrest at 86%, while the distal tibia (ankle) came in at 45% and the proximal tibia at 50%. The distal radius, despite being the most commonly fractured site, had a lower rate of about 27%.11PubMed Central. Risk Factor Analysis for Growth Arrest in Paediatric Physeal Fractures—A Prospective Study The distal femur’s growth plate contributes more to overall leg length than almost any other single plate in the body, and it seems to be less forgiving of injury.
Age matters too. Children closer to skeletal maturity at the time of injury were more likely to develop growth arrest, with an average age of about 13 in the affected group compared to roughly 9 in those who healed without problems. High-energy mechanisms like motor vehicle accidents or falls from significant heights tripled the risk compared to low-energy injuries.12PubMed Central. Risk Factor Analysis for Growth Arrest in Paediatric Physeal Fractures—A Prospective Study
The amount of initial displacement, meaning how far the bone fragments have shifted from their normal position, is another consistent risk factor. A study of distal tibial fractures in children found that initial displacement was the only statistically significant predictor of growth arrest, with a cutoff of about 5 millimeters separating higher-risk from lower-risk injuries.13PubMed. Growth arrest and its risk factors after physeal fracture of the distal tibia in children and adolescents Similarly, in ankle fractures involving the medial malleolus, children who developed physeal bars had significantly greater fracture displacement and greater involvement of the growth plate surface area.14PubMed. Risk Factors and Surgical Sequelae of Physeal Arrest in Pediatric Salter-Harris III and IV Medial Malleolus Fractures
How Growth Arrest Happens at the Cellular Level
When a growth plate fracture heals badly, the damaged area can be replaced by a bridge of bone rather than regenerating cartilage. This “physeal bar” tethers the two sides of the growth plate together and prevents normal lengthening in that area. If the bar forms near the edge of the plate, the bone grows unevenly, producing an angular deformity. If it forms centrally, the bone may simply stop getting longer.
Research into the biology of this process has shown that the bone bridge forms through direct bone production by cells recruited from the bone marrow, not through a cartilage intermediate. Mesenchymal cells infiltrate the injury site within days and begin differentiating into bone-forming cells, and within a week or two, new bone trabeculae are being laid down directly.15PubMed. Intramembranous ossification mechanism for bone bridge formation at the growth plate cartilage injury site This is a different process from how bones normally grow in length, and it explains why the damage is essentially permanent without intervention: the body does not spontaneously replace a bone bridge with new growth cartilage. Damage to a specific layer of the growth plate called the basement plate appears to be particularly likely to trigger bar formation.16Journal of Pediatric Orthopaedics. The Role of the Basement Plate in Physeal Bar Formation
Treating Growth Arrest After It Develops
If a physeal bar does form and the child still has significant growth remaining, surgeons can attempt to remove it. The procedure, called physeal bar resection, involves surgically excising the bone bridge and filling the gap with a material like fat or a synthetic filler to prevent the bone from simply bridging again.17PubMed Central. Pediatric physeal fractures and growth disturbance: current concepts and surgical approaches The goal is to allow the remaining healthy growth plate to resume normal function.
Bar resection alone does not always correct angular deformity that has already developed, though. A study comparing bar resection alone versus bar resection combined with guided growth (a technique that uses a small plate to temporarily slow growth on the longer side of the bone) found that the combination approach produced significantly better correction. Patients who had bar resection alone actually saw their angular deformity worsen in 40% of cases, while none of the patients who had the combined procedure experienced worsening.18PubMed Central. The efficacy of physeal bar resection with guided growth in the treatment of physeal arrest with angular limb deformity In severe cases, corrective osteotomies, where the bone is deliberately cut and re-angled, may be performed alongside bar resection to address deformity that has already occurred.19PubMed Central. Pediatric physeal fractures and growth disturbance: current concepts and surgical approaches
These are complex decisions that depend on how much growth a child has left. A 15-year-old with minimal remaining growth might not benefit from bar resection because the growth plate is about to close on its own. A 7-year-old with the same injury has years of growth ahead and stands to gain much more from an aggressive approach.
Overuse Injuries and the Young Athlete
Not all growth plate injuries come from a single fall or collision. Repetitive loading, the kind of stress that comes from throwing hundreds of pitches per week, tumbling routines in gymnastics, or distance running during a growth spurt, can gradually damage the growth plate without any acute fracture. These overuse injuries are sometimes called “stress physeal injuries,” and they have become a growing concern as children specialize in single sports at younger ages.20PubMed Central. Overuse Physeal Injuries in Youth Athletes Risk Factors, Prevention, and Treatment Strategies
The classic example is “Little Leaguer’s shoulder,” where the proximal humeral growth plate widens and becomes painful in a young pitcher. The wrist equivalent is seen in gymnasts whose distal radial growth plates endure repeated weight-bearing stress. These injuries generally resolve with rest and activity modification, but there is evidence that some lead to genuine growth disturbance if the athlete pushes through the pain.21PubMed Central. Physeal injuries in children’s and youth sports: reasons for concern? The challenge for parents and coaches is recognizing that persistent, location-specific pain in a young athlete’s joint is not just “growing pains” and deserves evaluation.
Regenerative Research and Future Directions
One of the frustrations of growth plate injuries is that damaged cartilage does not regenerate on its own, which is why a bone bridge forms in the first place. Researchers have been exploring whether stem cell therapies could change that. Mesenchymal stem cells, combined with growth factors that steer them toward becoming cartilage-producing cells, have shown promise in animal models for regenerating damaged growth plate tissue.22PubMed. Recent research on the growth plate: Mechanisms for growth plate injury repair and potential cell-based therapies for regeneration Gene therapy approaches, where chondrogenic growth factors or anti-inflammatory agents are delivered directly to the injury site, have also demonstrated some success in pre-clinical settings.23Current Stem Cell Research & Therapy. Repair of Injured Articular and Growth Plate Cartilage Using Mesenchymal Stem Cells and Chondrogenic Gene Therapy
None of these therapies are ready for clinical use yet. The gap between generating cartilage-like tissue in a lab and getting it to function as a working growth plate inside a growing child is enormous. But the research is active, and the basic biology of how growth plate injuries repair (or fail to repair) is better understood now than it was even a decade ago. For children who suffer severe growth plate injuries today, the existing tools of bar resection, guided growth, and osteotomy are effective in many cases. The hope is that the next generation of treatments will be able to restore the growth plate itself rather than working around its loss.
Growth Plate Fractures in Veterinary Medicine
Salter-Harris fractures are not unique to humans. Growing animals have the same vulnerable cartilage at the ends of their long bones, and the classification system applies across species. The problem is particularly significant in horses, where a young foal’s racing or athletic future can depend on how well a growth plate fracture heals.
In a review of 70 physeal fractures in horses, only 25% of treated animals eventually became sound, and younger foals (under about 4.5 months) had significantly better outcomes than older ones.24Veterinary Surgery. Physeal Fractures in the Horse II. Management and Outcome The sheer weight these animals place on their limbs makes conservative management less reliable than in children, and internal fixation is often preferred. A case report of a Salter-Harris Type II fracture in a foal’s proximal phalanx found that surgical repair with internal fixation produced a successful outcome where casting might have failed.25Journal of Equine Veterinary Science. The Surgical Repair of a Salter-Harris Type-2 Physeal Fracture of the Proximal Phalanx in a Foal Even with successful fracture healing, reduced longitudinal growth is a recognized trade-off: in one experimental study of equine femoral capital physeal fractures, the repaired femurs were measurably shorter than the opposite side despite the fractures uniting solidly.26PubMed. Evaluation of an interfragmentary compression system for the repair of equine femoral capital physeal fractures The parallel between the veterinary and human experience reinforces a basic truth about these injuries: growth plates are fragile, their healing is imperfect, and the window for intervention is narrow regardless of species.