Orthopaedic Surgery - Growth-Plate Injury

Basics

A growth-plate injury involves the physis, the cartilaginous region responsible for longitudinal growth of a child’s bone.

Not every physeal injury produces a growth abnormality. Most heal without long-term consequences, but injuries that significantly crush, displace, or destroy part of the growth plate may result in growth arrest, angular deformity, or limb-length discrepancy.

Common Sites

Physeal fractures occur most frequently in the long bones of growing children.

The growth plates most commonly injured include the:

Distal radius, distal tibia, phalanges, and proximal humerus.

Sites at Greatest Risk of Growth Disturbance

Although some physes are injured more frequently, the distal femoral and distal tibial physes are particularly important because injuries in these locations have a relatively high risk of subsequent growth disturbance.

Synonyms

Growth-plate injuries are also called physeal injuries or physeal fractures.

The term Salter-Harris fracture refers to the widely used classification system for traumatic injuries involving the physis.

Epidemiology

Physeal injuries account for approximately 15–30% of pediatric fractures.

They can occur throughout childhood but are particularly common during periods of rapid growth.

Age

Peak incidence generally occurs around 11–12 years in girls and 12–14 years in boys, corresponding approximately to the adolescent growth spurt.

Sex

Boys are affected more frequently overall, with some series reporting approximately twice as many injuries in boys as in girls.

Remaining Growth

Younger children have more growth remaining and therefore have a greater amount of potential deformity if a physeal arrest develops.

Conversely, a similar growth arrest occurring near skeletal maturity may have relatively little effect on final limb length or alignment.

Risk Factors

Adolescent boys are at increased risk because of their higher frequency of traumatic injuries during periods when the growth plate remains open.

Prevention of Sequelae

Early recognition of physeal damage may allow intervention before severe deformity develops.

Physeal Bar

A physeal bar is a bridge of bone that forms across part of an injured growth plate and can tether further growth.

If the bar is relatively small and the child has substantial growth remaining, surgical excision may allow more symmetric growth to resume.

Historically, bar resection has been considered when less than approximately 50% of the physis is involved, although candidacy also depends on bar location and remaining growth.

Other Corrective Options

When growth arrest has already produced substantial deformity, treatment may include:

Physeal bar resection, contralateral epiphysiodesis, ipsilateral hemiepiphysiodesis, corrective osteotomy, or limb-lengthening procedures.

Contralateral Epiphysiodesis

When a predictable limb-length discrepancy is expected, growth of the opposite limb may be intentionally slowed or stopped to improve final symmetry.

Etiology

Trauma is the most common cause of growth-plate injury.

Other processes may also damage the physis.

Nontraumatic Causes

Potential causes include:

Infection, tumor, medications or hormonal exposure, and severe thermal injury from excessive heat or cold.

Classification

The Salter-Harris classification is the standard system used to describe traumatic physeal fractures.

It is based on the relationship of the fracture line to the physis, metaphysis, and epiphysis.

Salter-Harris Type I

The fracture passes entirely through the physis, separating the epiphysis from the metaphysis without extending into either adjacent bone.

Because the germinal portion of the growth plate may remain intact, the prognosis is usually good after appropriate reduction.

Salter-Harris Type II

Type II is the most common physeal fracture pattern.

The fracture passes through the physis and then exits through the metaphysis, leaving a metaphyseal fragment attached to the epiphysis.

Salter-Harris Type III

The fracture passes from the physis through the epiphysis and into the joint surface.

Because it is intra-articular and crosses the growth plate, accurate reduction is important to restore both joint congruity and physeal alignment.

Salter-Harris Type IV

The fracture extends through the metaphysis, physis, and epiphysis, crossing the entire growth plate and entering the joint.

This pattern carries an increased risk of growth arrest and post-traumatic joint incongruity if reduction is inadequate.

Salter-Harris Type V

Type V represents a compression or crush injury of the physis.

It may be difficult to recognize on initial radiographs and is associated with a relatively high risk of premature growth arrest.

Rang Type VI

A so-called Type VI or Rang VI injury involves damage to the peripheral perichondral ring.

It is not part of the original Salter-Harris classification but may produce asymmetric growth and angular deformity.

Risk by Classification

In general, the risk of growth disturbance increases with increasing complexity of physeal injury.

Types III, IV, and V are particularly concerning because they either cross the articular surface, disrupt the germinal layer more extensively, or crush the physis.

Associated Injuries

Physeal trauma may occur with other injuries, including:

Ligament injury, neurovascular injury, and additional chest, abdominal, or head trauma in high-energy mechanisms.

Diagnosis

Accurate diagnosis requires knowledge of the normal appearance and timing of secondary ossification centers and physeal closure at each skeletal location.

A fracture may be difficult to identify if much of the epiphysis remains cartilaginous.

Signs and Symptoms

The most common findings are pain, swelling, and tenderness over the involved growth plate.

Visible deformity may be present if the fracture is displaced.

Lower-Extremity Injuries

Children with a lower-extremity physeal fracture may be unable or unwilling to bear weight.

Upper-Extremity Injuries

Upper-extremity fractures commonly produce pain, swelling, and reduced active range of motion.

Crepitus

Crepitus may occasionally be present but should not be deliberately elicited because repeated manipulation can worsen pain or displacement.

Physical Examination

The entire injured limb should be examined carefully.

Skin

The examiner should look for open wounds, abrasions, bruising, swelling, and skin compromise.

Any wound near a fracture should raise concern for an open injury.

Neurovascular Status

Distal pulses, capillary refill, sensation, and motor function should be documented before and after splinting or reduction.

Pathological Findings

The physis is organized into several histologic zones:

Resting zone, proliferative zone, hypertrophic zone, zone of provisional calcification, and adjacent metaphysis.

Site of Fracture Propagation

Many physeal fractures propagate through the relatively weak hypertrophic and provisional calcification regions.

Permanent Physeal Injury

Permanent growth disturbance may occur when the injury destroys growth-plate cells, causes marked displacement or malalignment of the physis, or produces a bony bridge across the plate.

Infection can similarly damage the growth plate and result in arrest.

Imaging

Plain Radiographs

Initial imaging should include AP and lateral radiographs of the involved region.

An oblique view may be useful when the fracture pattern remains unclear.

Comparison Views

Comparison with the opposite side may occasionally help in very young children, although this is not routinely required.

CT

CT is useful for complex fractures, particularly those with intra-articular extension, when precise definition of the fracture geometry is required for treatment planning.

It is especially valuable for Salter-Harris III and IV injuries around complex joints.

MRI

MRI is the most sensitive modality for evaluating established physeal damage, occult physeal injury, and physeal bars.

It clearly demonstrates cartilage and can distinguish the growth plate from surrounding bone.

Acute MRI Findings

Possible findings include:

Physeal widening, increased fluid-sensitive signal within the injured physis, and adjacent bone marrow edema.

Physeal Bar Mapping

MRI can define the size, position, and percentage of physeal involvement by a bony bridge.

Three-dimensional or semiautomated mapping may assist prognosis and surgical planning.

Ultrasound

Ultrasound can be useful in infants and very young children because substantial portions of the epiphysis remain cartilaginous and may not be visible on conventional radiographs.

Differential Diagnosis

In acute trauma, the primary concern is identifying whether the injury truly involves the physis.

In chronic cases, other causes of growth-plate damage must be considered.

Infection

Physeal or metaphyseal infection may be insidious and can produce growth disturbance long after the initial illness.

Other Causes

Tumor, metabolic disease, previous surgery, radiation, thermal injury, and prior trauma may also cause physeal arrest.

Treatment

Initial Measures

Immediate management includes immobilization, elevation, ice when appropriate, pain control, and assessment of neurovascular status.

Nondisplaced Fractures

Nondisplaced physeal fractures should be immobilized promptly in an appropriate splint.

Displaced Fractures

Displaced injuries generally require reduction under suitable analgesia or anesthesia.

Options may include procedural sedation, regional or hematoma block in appropriate fractures, or general anesthesia.

After reduction, the limb is splinted and repeat imaging is obtained to confirm alignment.

Early Follow-Up

Patients with physeal fractures should usually be reviewed within approximately 3–5 days, particularly when substantial swelling is present.

Splint to Cast Conversion

A splint is often used initially because it accommodates swelling.

After edema has decreased, commonly after approximately 1–2 weeks, a circumferential cast may be applied if continued immobilization is required.

Weight Bearing

Lower-extremity physeal fractures are often treated with restricted or non-weight bearing until adequate stability and healing are demonstrated.

Upper-extremity injuries are generally protected with a sling or other supportive device.

Duration of Immobilization

Many uncomplicated physeal fractures heal relatively quickly because of the vascularity and remodeling potential of children.

Immobilization frequently lasts approximately 3–4 weeks, although duration varies substantially by age, fracture location, stability, and treatment method.

Medication

Analgesia should be provided according to pain severity.

Persistent or escalating pain should prompt reassessment for complications such as compartment syndrome rather than simply increasing medication.

Surgery

Goal of Reduction

Restoring appropriate alignment is one of the most important methods of reducing the risk of later deformity.

For intra-articular physeal injuries, restoration of the joint surface is also essential.

Repeated Reduction Attempts

Repeated forceful reduction attempts should be avoided because additional manipulation may further injure the growth plate.

Delayed Reduction

Forceful closed reduction performed more than approximately 5–7 days after injury is generally avoided in many physeal fractures because healing has already begun and manipulation may damage the physis.

Management should instead be individualized according to deformity, fracture type, and remaining growth.

Open Reduction

Salter-Harris III and IV fractures may require open reduction when acceptable anatomic alignment cannot be achieved by closed techniques.

Internal Fixation

Fractures that remain unstable after reduction may require percutaneous pinning, screws, or other internal fixation.

Crossing the Physis

When fixation must cross an open physis, smooth pins placed as centrally and perpendicularly as practical are generally preferred because they minimize physeal injury.

Eccentric or threaded implants crossing the physis may increase the risk of growth disturbance.

Open Fractures

Open physeal fractures require urgent antibiotics, tetanus assessment, surgical irrigation and debridement, stabilization, and orthopaedic management.

Follow-Up

Prognosis

Most growth-plate fractures heal without major difficulty.

The likelihood of growth disturbance depends on fracture type, anatomic location, degree of displacement, quality of reduction, patient age, and extent of physeal injury.

Effect of Salter-Harris Type

Higher-grade Salter-Harris injuries generally have a greater risk of subsequent growth abnormality.

Effect of Skeletal Maturity

The closer the patient is to skeletal maturity, the less remaining growth exists and therefore the smaller the potential effect of a growth arrest on final limb length.

High-Risk Anatomic Sites

The distal femoral and distal tibial physes have relatively high rates of growth disturbance and warrant particularly careful follow-up.

Lower-Risk Sites

The distal radius and proximal humerus often tolerate physeal injury better because of their substantial remodeling potential and the pattern of growth at those sites, although growth arrest can still occur.

Complications

Growth Arrest

A portion or all of the physis may stop growing prematurely.

Complete arrest can produce limb shortening, whereas partial arrest may create progressive angular deformity.

Growth Disturbance

Asymmetric growth across an injured physis may result in varus, valgus, flexion, extension, or rotational deformity, depending on the location of the arrest.

Limb-Length Discrepancy

Loss of growth from a major physis may produce clinically significant shortening of the affected limb.

Malunion

A fracture that heals in poor alignment may produce deformity even without a true growth arrest.

Growth Acceleration

Children younger than approximately 10 years may occasionally demonstrate temporary overgrowth after fracture because of increased local blood flow and stimulation of growth.

The resulting length increase is usually modest, often approximately 5–10 mm.

Patient Monitoring

Children at increased risk of growth disturbance require prolonged surveillance.

This includes Salter-Harris III–V fractures and all significant distal femoral or distal tibial physeal injuries.

Duration

Follow-up should generally continue for at least 6–12 months, and longer when substantial growth remains or there is concern for partial arrest.

Clinical Assessment

The physician should compare limb lengths, angular alignment, gait, and joint motion.

Radiographic Assessment

Follow-up radiographs should assess whether the growth plate remains open and symmetric.

A growth-arrest line, sometimes called a Harris line, may form after the injury.

If subsequent growth is normal, this line should progressively move away from the physis in a parallel and symmetric fashion.

Failure of the line to migrate normally, or asymmetric tethering toward one side of the physis, may suggest developing growth arrest.