AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

In growing children, sprains and strains often result in potentially serious growth plate fractures and physeal fractures. These same sprains and strains in active adults are relatively benign injuries. This article discusses some of the important orthopedic history relative to the physes, relevant anatomy, classification systems, and some details of physeal fractures in specific areas of the body.

For excellent patient education resources, visit eMedicine's Bone, Joint, and Muscle Center. Also, see eMedicine's patient education article Sprains and Strains.

Related eMedicine topics:
Diaphyseal Femur Fractures
Diaphyseal Tibial Fractures

Related Medscape topics:
Resource Center Fracture
Specialty Site Orthopaedics
Specialty Site Pediatrics

History of the Procedure

In the 1500s, Ambroise Pare made the earliest known reference to what is now called the growth plate when he described the "appendices" of long bones. What Pare referred to as dislocations of these appendices is now called growth plate fractures. In 1727, Stephen Hales deduced the specific location of the growth plate. He noted that the distance between drill holes he made in the diaphyses of leg bones of chickens did not increase as the birds grew. From this he correctly concluded that longitudinal growth occurred at the ends of these long bones and not in the middle.

Less than 10 years later, the study of the growth plate took a big step forward when John Belchier introduced the scientific community to an important bone-staining method using the plant product called madder. The use of madder (Rubia tinctorum) actually dates back to biblical times, when it was used as a red dying agent for clothing.

Belchier noted that the bones of madder-fed animals stained red in their growth areas. This discovery led to the extensive madder dye experiments conducted by John Hunter (1728-1793) during the late 1700s (see Image 1). Hunter studied growing chickens and clearly demonstrated that longitudinal bone growth occurred because of new bone generated by the physes at the ends of long bones. John Hunter is frequently referred to as the father of the growth plate, as he was the first to study it in such detail.

Problem

Physeal fractures (growth plate fractures) may be defined as a disruption in the cartilaginous physis of long bones that may or may not involve epiphyseal or metaphyseal bone. These injuries are classified many ways. Poland earned credit for one of the first systems in 1898; his 4-part classification system progressed from a simple epiphyseal separation to an epiphyseal separation in which it is split in two. Many other classification systems followed, including a system suggested by Petersen in 1994. This system was constructed on the basis of a population-based epidemiologic study and arranged from the physis least involved progressing to the injury that posed the greatest threat to the physis.

Many classification systems have been used throughout the world, but the Salter and Harris (SH) classification is preferred and the accepted standard in North America to facilitate communication among health care professionals.^{1, 2, 3} This system was proposed in 1963 by Robert Salter and W. Robert Harris of Toronto. The various types of fracture patterns within the SH classification are described as follows:

• SH I: This fracture typically traverses through the hypertrophic zone of the cartilaginous physis, splitting it longitudinally and separating the epiphysis from the metaphysis. When these fractures are undisplaced, they may not be readily evident on radiographs because of the lack of bony involvement. In many instances, only mild to moderate soft-tissue swelling is noted radiographically. Clinical findings may be impressive (see Image 2); however, subsequent radiographs may demonstrate physeal widening or new bone growth along physeal margins, indicating the presence of a healing fracture (see Image 3). In general, the prognosis for this type of fracture is excellent. Usually, only closed reduction is necessary for displaced fractures; however, open reduction and internal fixation may be necessary if a stable satisfactory reduction cannot be maintained.
• SH II: The fracture splits partially through the physis and includes a variably sized triangular bone fragment of metaphysis (see Image 4). This fragment is often referred to as the Thurstan Holland fragment in honor of the British radiologist, Charles Thurstan Holland, who drew attention to its existence in 1929. Periosteum on the side of the Thurstan Holland fragment often remains intact, thus facilitating reduction. This particular fracture pattern occurs in an estimated 75% of all physeal fractures, and it is the most common physeal fracture. Image 5 illustrates an SH II fracture of the distal femur.
• SH III: This fracture pattern combines physeal injury with an articular discontinuity. This fracture partially involves the physis and then extends through the epiphysis into the joint. It has the potential to disrupt the joint surface. This injury is less common and often requires open reduction and internal fixation to ensure proper anatomic realignment of both the physis and the joint surface. Poland included a fracture pattern similar to this in his scheme, in which both epiphyseal pieces were seen as free-floating fragments separated from the metaphysis. Image 6 depicts a common SH III fracture of the distal tibia, a Tillaux fracture, on CT scan.
• SH IV: This fracture runs obliquely through the metaphysis, traverses the physis and epiphysis, and enters the joint. Good treatment results for this fracture are considered to be related to the amount of energy associated with the injury and the adequacy of reduction. The Thurstan Holland sign (ie, a Thurstan Holland fragment) is also seen with this fracture pattern. Image 7 illustrates such a fracture of the proximal tibia.
• SH V: These lesions involve compression or crush injuries to the physis and are virtually impossible to diagnose definitively at the time of injury. Knowledge of the injury mechanism simply makes one more or less suspicious of this injury. No fracture lines are evident on initial radiographs, but they may be associated with diaphyseal fractures. SH V fractures are generally very rare; however, family members should be warned of the potential disturbance in growth and that, if growth disturbance occurs, treatment is still available (depending on the child's age and remaining growth potential). Images 8-9 depict the SH V fracture pattern.
• SH VI: An additional classification of physeal fractures not considered in the original SH classification but now occasionally included is SH VI, which describes an injury to the peripheral portion of the physis and a resultant bony bridge formation that may produce considerable angular deformity. This injury was suggested by Mr. Lipmann Kessel, as follows: "A rare injury of growth plate results from damage to the periosteum or perichondral ring. . . following burns or a blow to the surface of the limb, for example a run over injury."⁴ Images 10-11 illustrate the SH VI fracture pattern.

Injuries to the physes are more likely to occur in an active pediatric population, in part due to the greater structural strength and integrity of the ligaments and joint capsules than of the growth plates. These binding ligamentous structures are 2-5 times stronger than the growth plates at either end of a long bone and, therefore, are less often injured in children sustaining excessive external loads to the joints.

Frequency

Mann and Rajmaira collected data on 2650 long bone fractures, 30% of which involved the physes.⁵ Neer and Horowitz evaluated 2500 fractures to the physes (growth plate) and determined that the distal radius was the most frequently injured (44%), followed by the distal humerus (13%), and distal fibula, distal tibia, distal ulna, proximal humerus, distal femur, proximal tibia, and proximal fibula.⁶

According to a 1972 retrospective analysis of 330 acute physeal injuries or growth plate injuries seen over the course of 20 years, males were affected more than twice as often as females. Females were most frequently affected at a younger age than males, at age 11-12 years compared to age 12-14 years in males. These findings correspond with the growth spurts (when the physes are weakest) of the respective sexes and with males' increased willingness to engage in high-risk activities. Within this population, upper extremity injuries were more frequent than lower extremity injuries overall.

Pathophysiology

Physeal fractures (growth plate fractures) are typically believed to occur through the zone of provisional calcification but may traverse several zones depending upon the type of external load application. For instance, with application of compression-type loads, the histologic zone of failure is typically the provisional calcification portion of the hypertrophic zone. Shear forces may also cause failure in the hypertrophic zone. Tension forces lead to failure of the proliferative zone.

Clinical

Patients typically complain of what seems to be localized joint pain, often following a traumatic event (eg, fall, collision). Swelling near a joint with focal tenderness over the physis is usually present (see Image 2). Lower extremity injuries present as an inability to bear weight on the injured side; upper extremity injuries present with complaints of impaired function and reduced range of motion, quite similar to ligamentous injury. Ligamentous laxity tests of the joints of the injured side may elicit pain and positive findings similar to those indicative of joint injury. (An SH III or SH IV fracture of the distal femur is the classic example.) Do not dismiss positive joint laxity test findings as only involving the related joint tissues.

INDICATIONS

Section 3 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

SH I and SH II physeal injuries (growth plate injuries) usually can be managed adequately with closed manipulative reduction. Upon reduction, these injuries are typically stable and casting suffices. At times, periosteal flaps or other local tissue may interpose into the fracture site and inhibit complete reduction. This complication may require surgical extraction of the tissues to enable satisfactory or anatomic reduction.^{7, 1, 2}

SH III and SH IV physeal injuries represent disruption of the physis and the epiphysis as well as intra-articular fracture. Intra-articular discontinuity can lead to early degenerative arthritis, and physeal discontinuity can disturb longitudinal growth. According to Bright,⁷ proper management of SH III and SH IV injuries requires anatomic reduction and internal fixation to restore anatomic alignment of the joint surfaces and proper alignment of juxtaposing physeal surfaces. Many cases have been presented in which nondisplaced fracture fragments have migrated subsequent to cast immobilization only.

SH V and VI physeal injuries often result in partial or complete growth arrest (physeal bar formation). As a result, physeal bar resection may be required or other surgical procedures may be necessary to prevent or correct deformity.³

RELEVANT ANATOMY

Section 4 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Technically, 2 growth plates may be considered to exist in immature long bones: the horizontal growth plate (physis) and the spherical growth plate (enables epiphyseal growth). For the purposes of this article, the horizontal growth plate is addressed. The horizontal growth plate is easily seen on radiographs of most growing long bones as a horizontal radiolucent region near the end of the bone. It may also be referred to as the cartilaginous growth plate.

The physis is an organized system of tissue located at the ends of long bones, consisting of an arrangement of chondrocytes surrounded by a matrix consisting of proteoglycan aggregates. The chondrocytes of the physis are divided into a system of zones based on different stages of maturation in the endochondral sequence of ossification and their function, as follows:

• Reserve/resting zone: This zone is immediately adjacent of the epiphysis. It consists of irregularly scattered chondrocytes with low rates of proliferation. This layer supplies developing cartilage cells and stores necessary materials (lipids, glycogen, proteoglycan aggregates) for later growth. Injury to this layer results in cessation of growth.
• Proliferative zone: Chondrocytes are flattened and stacked upon each other in well-defined columns. These cells produce necessary matrix and are responsible for longitudinal growth of the bone via active cell division.
• Hypertrophic zone: This zone is divided into maturation, degeneration, and provisional calcification zones. Cells increase in size, accumulate calcium within their mitochondria, and deteriorate, ultimately leading to cell death. Upon their death, calcium is released from matrix vesicles, impregnating the matrix with calcium salt. The calcification of the matrix is necessary for invasion of metaphyseal blood vessels, destruction of cartilage cells, and the formation of bone along the walls of the calcified cartilage matrix. No active growth occurs in this layer; columns of cells extending toward the metaphysis are at various stages of maturation. This is the weakest portion of the physis and is commonly a site of fracture or alteration (eg, widening, as in rickets).

The metaphysis, adjacent to the physis, is composed of primary and secondary spongiosa layers. Primary spongiosa is mineralized to form woven bone and is subsequently remodeled to form secondary spongiosa. Branches of the metaphyseal and nutrient arteries enter the secondary spongiosa and form closed capillary loops in the primary spongiosa.

The periphery of the physis consists of 2 elements: the groove of Ranvier and the perichondrial ring (of Lacroix). The groove of Ranvier is a wedge-shaped zone of cells contiguous with the epiphysis at the periphery. It supplies chondrocytes to the periphery of the physis, enabling lateral growth or increased width of the physis. Langenskiold proposed that cells from the reserve zone migrate into the region of the groove of Ranvier.⁸ The perichondrial ring is a dense fibrous ring that surrounds the physis and is critical to the overall stability of the growth plate. The perichondrial ring's stabilizing effect may be lost in pathologic conditions such as slipped capital femoral epiphysis (SCFE).

CONTRAINDICATIONS

Section 5 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Absolute contraindications to reduction of displaced growth plate fractures are few. They amount to the unusual situations in which the risks of sedation or general anesthesia are believed to dramatically outweigh the potential benefits of growth plate fracture reduction.

Relative contraindications to growth plate fracture reduction would be SH I or II fractures with clinically insignificant displacement. Also, fractures with perhaps somewhat greater displacement that present in a delayed fashion (perhaps 3 wk or so after injury) are contraindications. In such cases, the risks of the additional force that would have to be exerted on the growth plate must be weighed against the likelihood of spontaneous remodeling of the fracture over time.

WORKUP

Section 6 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Imaging Studies

• Many acute physeal injuries are not clearly visible on plain radiographs due to the cartilaginous-osseous nature and irregular contours of the physes.
• • Plain radiographs may depict physeal widening as the only sign of displacement. In order to help delineate the injury, 2 views (anteroposterior and lateral) are necessary. Occasionally, comparison views of the opposite extremity may be helpful. Comparison views can help establish occult separation of the physis, as in an SH I injury.
  • Radiographic stress views (varus and valgus) may be indicated in certain patients. They are not recommended in all instances, as stress maneuvers may cause further physeal damage. However, stress radiographs may be necessary in order to accurately diagnose physeal plate injury. Stress views may prove particularly useful to demonstrate separation between the epiphysis and metaphysis in injuries around the knee and elbow.⁹
• CT scans are at times necessary to delineate fragmentation and orientation of severely comminuted epiphyseal and metaphyseal fractures.¹⁰
• Bone scans are not particularly helpful, as the physes are normally relatively active on nuclear scans.
• Magnetic resonance imaging (MRI) has proven to be the most accurate evaluation tool for the fracture anatomy when performed in the acute phase of injury (initial 10 d). MRI can depict altered arrest lines and transphyseal bridging abnormalities prior to their being evident on plain radiographs.

TREATMENT

Section 7 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Medical therapy

Physeal fractures are very commonly treated nonoperatively. Factors that affect treatment decisions include the severity of the injury, the anatomic location of the injury, the classification of the fracture, the plane of the deformity, the age of the patient, and the growth potential of the involved physis. Most SH I and II injuries can be treated with closed reduction and casting or splinting and then reexamination in 7-10 days to evaluate maintenance of the reduction.

Closed reductions through manipulation and traction need to be performed carefully, with the patient (and the patient's involved musculature) as relaxed as possible in order to avoid unnecessary wrestling of the bony components that may lead to grating of the physis on sharp metaphyseal bone fragments and potential damage to the physis. Less than satisfactory reductions are preferred over repeated attempts at reduction that may damage the germinal layer of cells within the physis. To avoid physeal damage, efforts at reduction should focus more on traction and less on forceful manipulation of the bone fragments.

Disruption of the physis may warrant restoration of its congruency in order to ensure proper joint mechanics. Angular deformities may also occur, due to malreduction or partial growth arrest. The location and direction of the deformity need to be considered when planning treatment. In general, greater angular deformity can be tolerated in the upper extremity than in the lower extremity, more valgus deformity can be tolerated than varus, and more flexion deformity can be tolerated than extension. More proximal deformities of the lower extremity (in the hip) are better compensated for than distal deformities (the knee and, least of all, the ankle). Spontaneous correction of angular deformities is greatest when the asymmetry is in the plane of flexion or extension (ie, the plane of joint motion), with function often returning to normal unless the fracture occurs near the end of growth.

The age of the patient at the time of injury is of paramount importance in helping predict clinical outcomes because more correction can be anticipated in younger patients. For instance, injuries to the physes of 14- to 15-year-old girls or 17- to 18-year-old boys are of little consequence due to their limited growth potential. As a result, any growth plate injury is unlikely to be clinically significant. However, injuries in younger children with full growth potential can cause significant problems and a wide range of clinical effects.

Surgical therapy

More severe injuries involving intra-articular fractures (SH III and IV) typically require anatomic reduction with open reduction and internal fixation that avoids crossing the physis. Smooth pins should parallel the physis in the epiphysis or metaphysis, avoiding the physis. Oblique application of pins across the physis should be considered only when satisfactory internal fixation is unattainable with transverse fixation. Any internal fixation devices should be easily removable yet adequate for internal fixation.

Type V fractures are rarely diagnosed acutely, and unfortunately, treatment is often delayed until the formation of a bony bar across the physis is evident. A high level of clinical suspicion is necessary to detect this complication early. In many cases, "early" may not be until 6 months or more after the injury.

Follow-up

Long-term follow-up is essential to determine whether or not complications will occur. Most physeal injuries (growth plate injuries) should be reevaluated in the short term to ensure maintenance of reduction and proper anatomic relationships. Some physeal fractures (growth plate fractures) are more problematic than others when it comes to risk of growth arrest. Physeal fractures that are considered to be at increased risk for growth arrest include fractures to the following growth plates:

• Distal femur
• Distal tibia
• Distal radius and ulna
• Proximal tibia
• Triradiate cartilage

After initial fracture healing has occurred, physeal fractures require additional follow-up radiographs 6 months and 12 months following injury to assess for growth disturbance. Management of such physeal fractures can thus be divided into 2 phases. The first phase involves ensuring bone healing, and the second phase is monitoring growth.

For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education article Sprains and Strains.

COMPLICATIONS

Section 8 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Growth acceleration

Growth acceleration is a possible complication of physeal injuries; however, it is uncommon. This complication usually occurs in the first 6-18 months after the initial injury. The rapid healing of the physis enables an increased vascular response that is usually of shorter duration than that for healing of bony fractures. Accelerated growth patterns also may be associated with the use of implants and fixation devices that may stimulate longitudinal growth. The greater growth is rarely significant but may require future assessment by the clinician. Treatment for this acceleration in adolescents may involve an epiphysiodesis of the longer limb to avoid producing disproportionate limbs. If more than 6 cm of correction is desired, this is not a treatment option, and the clinician may consider lengthening procedures for bilateral limb-length equilibration.

Growth arrest

Complete growth retardation or partial growth arrest may result in progressive limb-length discrepancies. Complete growth arrest is uncommon and depends on when the injury to the physis occurs in relation to the remaining skeletal growth potential. The younger the patient, the greater the potential for problems associated with growth.

Premature partial growth arrest is far more common and can appear as peripheral or central closures. These can result in angular deformities and limb-length discrepancies. Premature partial arrests are produced when a bridge of bone (bone bar/bridge) forms, connecting metaphysis to epiphysis, traversing the physis. This bone bar inhibits growth, and the size and location of this bar determines the clinical deformity. For example, if the bar is located medially in the physis of the distal femur, the normal physis continues to grow laterally, producing a varus deformity (genu varum), and vice versa for a genu valgum deformity. Recent investigation into gait analysis for patients with genu valgum deformity revealed improvements in cosmesis and corrected joint kinematics with hemiphyseal stapling. Anterior bone bars in the distal femoral physis allow for normal physeal growth posteriorly but result in a genu recurvatum deformity.

Similarly, central growth arrests result in tented lesions of the physis and epiphysis due to a central osseous tether with the metaphysis, resulting in the characteristic physeal coning. As the physis tries to push the epiphysis away from the metaphysis, the bony bridge hypertrophies in an effort to overcome the increased tension placed on it. Bone tissue under constant tension usually atrophies, but in this instance, a dense reactive cortical bone develops.

Some longitudinal growth continues in patients with growth retardation, though at a much slower rate; thus, a progressive shortening of the limb occurs. Partial growth arrests may be visible on radiographs as early as 3-4 months postinjury or may be delayed as long as 18-24 months. Follow-up checks may be necessary for 1-2 years postinjury to monitor physeal healing and growth response.

Articular problems are also a possibility, particularly in physeal fractures that lead to discontinuities of the articular surface (ie, SH III, SH IV). These lesions can result in intra-articular step-offs and early degenerative joint disease if they are not properly treated and anatomically reduced. Central growth arrest can promote the physeal tenting phenomena and, ultimately, result in a deformed articular surface.

OUTCOME AND PROGNOSIS

Section 9 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

High-risk and significant-risk fractures

Distal femur fractures

Distal femoral fractures account for approximately 5% of all physeal fractures (growth plate fractures). Displacement of the fracture in the sagittal plane may be associated with neurovascular injury in the popliteal fossa and instability on closed reduction. A common mechanism of injury is hyperextension causing an anterior displacement of the epiphysis. Physeal fracture displacement in the coronal plane is not associated with other injuries, and the joint may be stable after closed reduction.¹¹

Clinically, the thigh may appear angulated and shortened as compared with the contralateral thigh; and pain, knee effusion, and soft-tissue swelling usually are severe. Hemarthrosis may be more severe in SH III and SH IV fractures, and vascular examinations may reveal diminished or absent distal pulses. Neurologic symptoms also may be evident distally due to disruption of the posterior tibial and common peroneal nerve distributions.

Injuries to the distal femoral physis may result in angular deformities. Certain levels of angulation are acceptable. Posterior angulation up to 20° remodels in children younger than 10 years; but injuries in adolescent patients do not remodel, and these patients do not tolerate this degree of angulation. Varus and valgus angulations are less acceptable; no angulation greater than 5° is acceptable for the distal femoral physis.

Treatment for distal femoral physeal fractures varies according to severity of injury. Displaced SH I or SH II fractures are treated with closed reduction and splinting with hip spica. SH III and SH IV injuries usually require anatomic reduction, which cannot be obtained with closed reduction, and are very often unstable. Operative treatment is required because even slight residual displacement can result in formation of a bone bar that causes limb-length discrepancy and angular deformity.

Complications of distal femoral fractures include growth arrest (partial or complete) with progressive angulation, shortening, or both in 30-80% of patients. Physeal fractures of the distal femur (particularly the common SH I and SH II fracture patterns) have been shown to be associated with an approximately 50% rate of growth disturbance.¹²

Because the incidence of growth arrest is high, even with satisfactory reduction, a lower extremity limb-length discrepancy of more than 2 cm may develop in one third of patients. Shortening and angulation are related more to degree of initial displacement than to the accuracy of the reduction. An angulation deformity of more than 5° may develop in one third of patients. A persistent angular deformity in the coronal plane may not correct spontaneously with further growth.

Distal tibia fractures

Fractures of the distal end of the tibia in children often involve the physis. They are of particular importance because partial growth arrest can occur and result in angular deformity, lower extremity limb-length discrepancy, incongruity of the joint surface, or a combination of these. Triplane and Tillaux fractures are the 2 distinct types of distal tibial fractures.

In a triplane fracture classification, 2 types of fractures exist: 2-part and 3-part fractures. A 2-part fracture is a type of SH IV fracture that primarily occurs when the medial portion of the distal tibial epiphysis is closed. Three-part fractures are a combination of SH II and SH III fractures that occur when only the middle portion of the distal tibial epiphysis is closed. This injury involves fracture of the anterolateral portion of the epiphysis of the distal tibia (similar to Tillaux fracture) and fracture of a large posterior fragment comprising the posterior and medial portions of the tibial epiphysis plus a large metaphyseal fragment of variable size; the fibula also may be fractured. These injuries most commonly occur just before epiphyseal closure and are due to external rotation forces.

Tillaux fractures are SH III fractures involving avulsion of the anterolateral tibial epiphysis. This portion of epiphysis is involved because the physis of the distal tibia closes in the middle first. The medial portion then closes, and finally, the lateral portion closes. This injury occurs in older adolescents, after the middle and medial parts of epiphyseal plate have closed but before the lateral part closes (usually in adolescents aged 12-15 y). Since this fracture occurs in adolescents with relatively mature growth plates, minimal potential exists for deformity due to growth plate injury.

Treatment of displaced SH III and SH IV fractures of the distal tibia require open reduction. This injury leads to premature physeal closure unless it is anatomically reduced. Development of an angular deformity is possible. Varus deformities, secondary to an osseous bridge formation on the medial aspect of the plate, are the most common complications found with distal tibia growth plate injuries. Limb shortening is the second most common problem associated with these injuries.

Kling et al, when evaluating distal tibial physeal fractures that required open reduction, suggested that SH III, SH IV, and perhaps SH II fractures of the distal end of the tibia commonly cause disturbance of growth in the tibia and that anatomic reduction of the physis by closed or open means may decrease the incidence of these disturbances of growth, including shortening and varus angulation of the ankle.¹³ SH IV fracture of the distal tibia has indeed been associated with premature physeal closure unless anatomically reduced, usually with internal fixation. 

A high rate of premature physeal closure (PPC) has been reported to occur in SH type I or II fractures of the distal tibia.  Rohmiller et al reported a PPC rate of 39.6% in SH type I or II fractures of the distal tibia physis and determined that fracture displacement following reduction was the most important determinant of PPC development.¹  Barmada et al investigated the incidence and predictors of PPC after distal tibia SH type I and II fractures and found that when residual gapping of the physis was greater than 3 mm following reduction, the incidence of PPC was 60%; when the physeal gap was less than 3 mm, there was a 17% incidence of PPC. Upon open reduction of residual gapping, the periosteum was found to be entrapped within the physis, thereby preventing closure of the gap and preventing appropriate recreation of the anatomy.¹⁴

Distal radius and ulna fractures

Physeal injuries of the distal ulna occur much less frequently than those of the distal radius, but physeal injuries of the distal ulna are associated with a higher incidence of growth arrest, due to the ulna deriving 70-80% of its longitudinal growth from its distal physis. As a result, growth arrest can cause significant ulnar shortening.

The distal radial physis is the most frequently injured physis in children, usually occurring in children aged 6-10 years. Children typically sustain the injury by falling on an outstretched hand. A great majority of these injuries are SH I and SH II fractures. The distal radial and ulnar physes provide 75-80% of total growth of the forearm, so potential for remodeling and correction of any deformity is excellent.¹⁵ Lee et al found that significant distal radial growth disturbance occurred in about 7% of physeal fractures¹⁶; the rate of distal ulnar growth arrest following physeal fracture is probably at least as high.

The acceptable amount of residual displacement for distal radial and ulnar fractures is not specifically known; however, 30% physeal displacement heals readily, and 50% displacement may often completely remodel in 1.5 years.

Proximal tibia fractures

While fractures involving the tibia and fibula are the most common lower extremity pediatric fractures, those involving the proximal tibial epiphysis are among the most uncommon but have the highest rate of complications. When displacement occurs, the popliteal artery is vulnerable. At the tibial metaphysis, the artery is just posterior to the popliteus muscle. Moore and Mackenzie found that in SH I injuries, half are nondisplaced and diagnosed by stress radiographs.¹⁷ SH I injuries occur at an earlier age (average age 10 y). SH II are the most common type, and one third are nondisplaced. SH III injuries are often associated with lateral condyle fractures or medial collateral ligament (MCL) injury. SH IV injuries are often associated with angular deformity. SH V injuries are usually diagnosed retrospectively. Anterior physis closure can cause significant genu recurvatum.

Complications of these injuries include vascular insufficiency and peroneal nerve palsy, however transient.

Triradiate cartilage fractures

Traumatic disruptions of the acetabular triradiate cartilage occur infrequently and may be associated with progressive acetabular dysplasia and subluxation of the hip. The volume of cartilage in a child's acetabulum allows a greater capacity for energy absorption than in adults. Thus, in children, fractures of the acetabulum are consistently the result of high-energy trauma. Unfortunately, a younger age at the time of injury is associated with a greater chance of developing acetabular dysplasia.

Disruption of the acetabular triradiate cartilage in patients older than 12 years results in minimal subsequent growth disturbance; however, in younger patients, acetabular growth abnormality is a frequent complication. Growth abnormalities include shallow acetabula and progressive subluxation of the hip.

Triradiate cartilage injuries occurring during adolescence result in fewer growth changes in acetabular morphology and hip joint congruencies. However, in younger children, especially those who are younger than 10 years, acetabular growth abnormality is a frequent complication of this injury and may result in a shallow acetabulum similar to that seen in patients with developmental dysplasia of the hip (DDH). By the time patients reach skeletal maturity, disparate growth increases the incongruity of the hip joint and may lead to progressively more severe subluxation of the hip. Acetabular reconstruction may be necessary to correct the gradual subluxation of the femoral head.

Bucholz et al found 9 patients with triradiate physeal-cartilage injury who were classified according to the degree of displacement and the probable type of growth-plate disruption.¹⁸ They determined that 2 main patterns of injury occurred. The first was a shearing (SH I or II) growth mechanism injury, with central displacement of the distal portion of the acetabulum. This injury pattern seemed to have a favorable prognosis for continued normal acetabular growth, although occasional premature closure of the triradiate physes occurred. The other pattern appeared to be a crushing SH V growth mechanism injury; this type has a poor prognosis, with premature closure of the triradiate physes occurring secondary to the formation of a medial osseous bridge. Prognosis is dependent on the age of the patient at the time of injury and on the extent of chondro-osseous disruption.

Stubbed great toe

Images 12-13 illustrate the respective radiographic and clinical appearance of an injury that has been termed the pediatric stubbed great toe. It is a somewhat occult open fracture due to the fact that the growth plate of the distal phalanx is remarkably close to the nail plate. When a subungual hematoma occurs in conjunction with a growth plate fracture, this does in fact represent an open fracture. In the great toe (or at times lesser toes), this injury has been termed a Pinckney fracture or Pinckney lesion.¹⁹ In the hand, such fractures of the terminal phalanx may be called Seymour fractures.²⁰

FUTURE AND CONTROVERSIES

Section 10 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Growth plate transplantation

Several experiments have been performed to evaluate the efficacy of interpositioning materials (eg, bone wax, fat, cartilage, silicon rubber, polymethylmethacrylate) into defects resulting from physeal bar excision. No single material has been deemed superior in the prevention of physeal bar reformation. Cartilage may prove ideal, and several possible sources for graft material exist, but each has associated difficulties such as the following:

• Apophyseal cartilage may lack the growth potential of epiphyseal cartilage.
• Laboratory-procured chondrocyte allograft transplants may take a long time to develop and may not have any real possibility for interhuman transfer due to the impending immune response.
• In physeal cartilage transfer, difficulties abound in procuring and transferring physes from one site to another.

Tissue engineering

Most of the research involved in cartilage regeneration has focused on articular cartilage, but much of what may be learned through research may be applicable to growth plate cartilage. At present, no reliable means of regeneration exists. Cartilage is unable to regenerate itself, partly because of its low cellularity and lack of vascular supply. In addition, chondrocytes in articular cartilage are well differentiated, and the number of multipotent progenitor cells is relatively low. As a result, cartilage is able to heal the margins of damage but does not form a scar to join the edges of the defect together.

Many tissue-engineering strategies have been developed, including implantation of chondrogenic cells at various developmental stages into the defect site, implantation of cartilage itself (ie, osteochondral autograft/mosaic arthroplasty), cartilage transplantation, and allogenic grafts. Periosteal and perichondrial tissue grafts have been considered because of their stockpile of multipotent osteochondral progenitor cells. The use of scaffolds to provide a substrate for chondroprogenitor cell attachment and migration across cartilaginous defects has been studied as well.

These techniques have had variable success. Tissue scaffolding has proven effective at overcoming some deficiencies in tissue engineering. Collagen, a natural tissue, and poly-lactide-co-glycolide (PLGA), a polymer that elicits small acute immune responses, have shown promise as cartilage repair scaffolds. Chitin has recently been determined to be effective as a scaffolding for attaching and carrying stem cells for the repair of growth plate defects.

Some studies have combined gene therapy and tissue-engineering approaches to regenerate articular cartilage defects in the hope of application toward epiphyseal cartilage repair. One such study employed a retroviral vector to introduce the human bone morphogenic protein-7 (BMP-7) complementary DNA into periosteal-derived rabbit mesenchymal stems cells. BMP-7 stimulates the synthesis of type II collagen and aggrecan. Grafts containing the BMP-7 gene modified cells consistently showed complete or near-complete articular cartilage regeneration at 8 and 12 weeks; grafts from control groups exhibited poor regeneration.

The future also holds promise for specific intracellular signaling approaches to posttraumatic disturbances of the growth plate. At the University of Massachusetts, Leboy et al found that important regulators of physeal chondrocyte hypertrophy include special bone morphogenic proteins: activated cytoplasmic proteins (called Smads) and multifunctional transcription factors (called Runx proteins).²¹ Another potent stimulator of embryonic epiphyseal cartilage is growth differentiation factor 5 (GDF-5). Buxton and colleagues found that GDF-5 promotes both cell adhesion and proliferation during limb development.²²

MULTIMEDIA

Section 11 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Media file 1:  Growth plate (physeal) fractures. John Hunter (1728-1793), the "father of the growth plate."
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Media file 2:  Growth plate (physeal) fractures. Clinical appearance of the knee of a patient with a minimally displaced Salter-Harris I fracture of the distal femur. Impressive swelling was noted adjacent to the joint, but no evidence of intra-articular swelling was present. The patient was markedly tender to palpation about the distal femoral physis.
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Media file 3:  Growth plate (physeal) fractures. Anteroposterior radiograph of the knee of the patient from Image 2. Note subtle physeal widening confirming the diagnosis of a Salter-Harris I fracture of the distal femur.
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Media file 4:  Growth plate (physeal) fractures. Anteroposterior ankle radiograph demonstrating an impressively displaced Salter-Harris II fracture of the distal tibial epiphysis (along with comminuted fracture of distal fibular diaphysis).
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Media file 5:  Growth plate (physeal) fractures. Displaced Salter-Harris II fracture of the distal femur. The large Thurstan Holland (metaphyseal) fragment may serve an important fixation point for either a Steinmann pin or a lag screw.
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Media file 6:  Growth plate (physeal) fractures. Multiple computed tomography (CT) scan images depicting a displaced Salter-Harris III fracture of the distal anterolateral tibial epiphysis (ie, Tillaux fracture).
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Media file 7:  Growth plate (physeal) fractures. Displaced Salter-Harris IV fracture of the proximal tibia. The lateral portion of the epiphysis (with the Thurstan Holland fragment) and the medial portion of the epiphysis are independently displaced (ie, each are free-floating fragments).
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Media file 8:  Growth plate (physeal) fractures. The Salter-Harris V fracture pattern must be strongly suspected whenever the mechanism of injury includes significant compressive forces. This is the initial injury radiograph of a child's ankle that was subjected to significant compressive and inversion forces. It demonstrates minimally displaced fractures of the tibia and fibula with apparent maintenance of distal tibial physeal architecture.
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Media file 9:  Growth plate (physeal) fractures. Follow-up radiograph of the ankle of the child in Image 8. This radiograph depicts growth arrest secondary to the Salter-Harris V nature of the injury. Note the markedly asymmetric Park-Harris growth recovery line, indicating that the lateral portion of the growth plate continues to function and the medial portion does not.
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Media file 10:  Growth plate (physeal) fractures. Mortise radiograph demonstrating somewhat subtle physeal injury to distal tibia. The Salter-Harris VI pattern may be suspected based upon history and physical examination findings. In this case, the radiograph indicates that it is quite likely that a small portion of the peripheral medial physis (as well as a small amount of adjacent epiphyseal and metaphyseal bone) has been avulsed.
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Media file 11:  Growth plate (physeal) fractures. Clinical photograph of the patient from Image 5. This mechanism of injury and physical examination findings are consistent with the Salter-Harris VI physeal injury pattern. Some may also refer to this injury type as a Kessel fracture.
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Media file 12:  Growth plate (physeal) fractures. Radiographic evidence of a pediatric stubbed great toe.
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Media file 13:  Growth plate (physeal) fractures. Clinical appearance of a pediatric stubbed great toe. Note the subungual hematoma, representative of an open fracture.
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Media type:  Photo

REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

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