Chapter 7: Physeal Injuries and Growth Disturbances

Karl E. Rathjen, Harry K.W. Kim

Chapter Outline

Introduction

One of the unique aspects of pediatric orthopedics is the presence of the physis (or growth plate), which provides longitudinal growth of children's long bones. Physeal injuries are a common and unique feature of children's bony injuries, in part because the physis is structurally more susceptible to loads that would produce metaphyseal or juxta-articular fractures in adults.15,28,63,81,112,117,135,137,141 Physeal injury may occur in a variety of ways in addition to trauma.14,15,19,23,26,32,38,52,65,78,88,91,123,125,136,150,154,156 Although physes, similar to the children with them, are resilient to permanent injury, uneventful outcomes are by no means assured.1,10,17,20,25,29,61,76,90,104,106,110,113,122,134,143 In this discussion of management of physeal injuries and associated growth disturbances the term physis is used rather than “growth plate.” 

Physeal Anatomy

Normal Physeal Anatomy

Gross

Five regions characterize long bones: The bulbous, articular cartilage-covered ends (epiphyses) tapering to the funnel-shaped metaphyses, with the central diaphysis interposed between the metaphyses. During growth, the epiphyseal and metaphyseal regions are separated by the organized cartilaginous physis, which is the major contributor to longitudinal growth of the bone. The larger long bones (clavicle, humerus, radius, ulna, femur, tibia, and fibula) have physes at both ends, whereas the smaller tubular bones (metacarpals, metatarsals, and phalanges) usually have a physis at one end only. 
At birth, with the exception of the distal femur and occasionally the proximal tibia, all of the epiphyses which are mentioned above are purely cartilaginous. At various stages of postnatal growth and development, a secondary ossification center forms within the epiphysis. This development helps define the radiolucent zone of the physis, which persists until the physis closes at skeletal maturation. Typical ages for appearance of the major secondary ossification centers and physeal closure are summarized in Figures 7-1 and 7-2
Figure 7-1
 
Typical age (and range) of development of the secondary ossification centers of the epiphyses in the (A) upper extremity and (B) lower extremity.
Typical age (and range) of development of the secondary ossification centers of the epiphyses in the (A) upper extremity and (B) lower extremity.
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Figure 7-1
Typical age (and range) of development of the secondary ossification centers of the epiphyses in the (A) upper extremity and (B) lower extremity.
Typical age (and range) of development of the secondary ossification centers of the epiphyses in the (A) upper extremity and (B) lower extremity.
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Figure 7-2
 
Typical age (and range) of closure of physes in the (A) upper extremity and (B) lower extremity.
Typical age (and range) of closure of physes in the (A) upper extremity and (B) lower extremity.
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Figure 7-2
Typical age (and range) of closure of physes in the (A) upper extremity and (B) lower extremity.
Typical age (and range) of closure of physes in the (A) upper extremity and (B) lower extremity.
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Microscopic Structure

Physis is highly organized, yet dynamic structure that consists of chondrocytes undergoing proliferation, differentiation, and formation of complex extracellular matrix. The extracellular matrix is composed of type II collagen fiber network, aggrecans, and noncollagenous proteins, such as cartilage oligomeric protein and matrilin-3. Type IX and XI collagens are minor collagens found in the physis. Type X collagen is also found in the physis; however, its synthesis is limited to the hypertrophic zone and is a distinguishing feature of hypertrophic chondrocyte. 
Understanding of physeal injuries requires knowledge of normal physeal morphology.135 Histologically, the physis is divided into four zones oriented from the epiphysis to the metaphysis: Germinal (reserve), proliferative, hypertrophic, and provisional calcification (Fig. 7-3). The proliferative zone is the location of cellular proliferation, whereas the hypertrophic and provisional calcification zones are characterized by extracellular matrix production, cellular hypertrophy, apoptosis, extracellular matrix calcification, and vascular invasion of the lacunae of the terminal hypertrophic chondrocytes. Collagen fiber orientation is horizontal in the germinal zone whereas it is vertical in the proliferative and hypertrophic zones, in line with growth and columnar arrangement of cells.8 Collagen content is lower in the proliferative and hypertrophic zones compared with the germinal zone. The differences in the collagen content and fiber orientation of different physeal zones have important implications in the mechanical behavior of each zone to mechanical loading.9 For instance, greater strains are observed in the proliferative and hypertrophic zones compared with the germinal zone following compression loading. 
Figure 7-3
Schematic diagram of the organization of the physis.
 
Four zones are illustrated: The germinal, proliferative, hypertrophic, and provisional calcification (or enchondral ossification) layers. Note also the groove of Ranvier and the perichondral ring of LaCroix.
Four zones are illustrated: The germinal, proliferative, hypertrophic, and provisional calcification (or enchondral ossification) layers. Note also the groove of Ranvier and the perichondral ring of LaCroix.
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Figure 7-3
Schematic diagram of the organization of the physis.
Four zones are illustrated: The germinal, proliferative, hypertrophic, and provisional calcification (or enchondral ossification) layers. Note also the groove of Ranvier and the perichondral ring of LaCroix.
Four zones are illustrated: The germinal, proliferative, hypertrophic, and provisional calcification (or enchondral ossification) layers. Note also the groove of Ranvier and the perichondral ring of LaCroix.
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The peripheral margin of the physis comprises two specialized areas important to the mechanical integrity and peripheral growth of the physis (Fig. 7-3). The zone (or groove) of Ranvier is a triangular microscopic structure at the periphery of the physis, containing fibroblasts, chondroblasts, and osteoblasts. It is responsible for peripheral growth of the physis. The perichondral ring of LaCroix is a fibrous structure overlying the zone of Ranvier, connecting the metaphyseal periosteum and cartilaginous epiphysis, and has the important mechanical function of stabilizing the epiphysis to the metaphysis. 
The epiphysis and secondary ossific nucleus must receive blood supply for viability.155 Dale and Harris46 identified two types of blood supply to the epiphysis (Fig. 7-4). Type A epiphyses (such as the proximal humeral and proximal femoral epiphyses) are nearly completely covered with articular cartilage; therefore, most of the blood supply to the epiphysis must enter from the perichondrium in a distal to proximal direction. The blood supply to these epiphyses may be easily compromised by epiphyseal separation. A complete disruption of the epiphyseal vasculature, however, may not produce an extensive ischemic damage to the physis if the metaphyseal vasculature is intact.87 The studies using multiphoton microscopy also suggest that growth plate nutrition is not unidirectional from the epiphysis to the metaphysis as traditionally believed but is contributed by the epiphyseal, metaphyseal, and circumferential perichondrial vasculature.53,161 Type B epiphyses (such as the proximal and distal tibia and the distal radius) have only a portion of their surface covered with articular cartilage and are theoretically less susceptible to devascularization from epiphyseal separation. 
Figure 7-4
Classification of epiphyseal blood supply according to Dale and Harris.
 
A: Type A epiphyses are nearly completely covered by articular cartilage. Blood supply must enter via the perichondrium. This blood supply is susceptible to disruption by epiphyseal separation. The proximal femur and proximal humerus are examples of type A epiphyses. B: Type B epiphyses are only partially covered by articular cartilage. Such epiphyses are more resistant to blood supply impairment by epiphyseal separation. The distal femur, proximal and distal tibia, and distal radius are clinical examples of type B epiphyses.
A: Type A epiphyses are nearly completely covered by articular cartilage. Blood supply must enter via the perichondrium. This blood supply is susceptible to disruption by epiphyseal separation. The proximal femur and proximal humerus are examples of type A epiphyses. B: Type B epiphyses are only partially covered by articular cartilage. Such epiphyses are more resistant to blood supply impairment by epiphyseal separation. The distal femur, proximal and distal tibia, and distal radius are clinical examples of type B epiphyses.
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Figure 7-4
Classification of epiphyseal blood supply according to Dale and Harris.
A: Type A epiphyses are nearly completely covered by articular cartilage. Blood supply must enter via the perichondrium. This blood supply is susceptible to disruption by epiphyseal separation. The proximal femur and proximal humerus are examples of type A epiphyses. B: Type B epiphyses are only partially covered by articular cartilage. Such epiphyses are more resistant to blood supply impairment by epiphyseal separation. The distal femur, proximal and distal tibia, and distal radius are clinical examples of type B epiphyses.
A: Type A epiphyses are nearly completely covered by articular cartilage. Blood supply must enter via the perichondrium. This blood supply is susceptible to disruption by epiphyseal separation. The proximal femur and proximal humerus are examples of type A epiphyses. B: Type B epiphyses are only partially covered by articular cartilage. Such epiphyses are more resistant to blood supply impairment by epiphyseal separation. The distal femur, proximal and distal tibia, and distal radius are clinical examples of type B epiphyses.
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Regulation of Growth

Various systemic (hormonal) and local (paracrine) factors, as well as the mechanical factors, regulate and influence the longitudinal growth.115 Systemic factors that influence physeal function include growth and thyroid hormones, androgen, estrogen, vitamin D, and glucocorticoids. Estrogen and not androgen controls the growth spurt and normal physeal closure at skeletal maturity in both sexes.149 Local factors that influence chondrocyte proliferation and differentiation include parathyroid hormone-related protein, Indian hedgehog protein, transforming growth factor-B, insulin-like growth factor-1, and fibroblast growth factor. In a physis, chondrocyte hypertrophy contributes most to the longitudinal growth followed by extracellular matrix production and cell division.163 The physes with more rapid growth, such as the proximal tibial physis in comparison to the proximal radial physis, have a larger increase in cell size. Experimental studies show that static, sustained loading decreases chondrocyte proliferation, cell height, and the thickness of the hypertrophic zone.158 Hueter–Volkmann law states that abnormal compression inhibits growth whereas distraction stimulates it. A varying degree of dynamic physiologic loading, however, has not been shown to significantly alter longitudinal bone growth.114 

Contributions to Longitudinal Growth and Maturation Characteristics of Selected Physes

Growth of long bones is more complex than simple elongation occurring at their ends. However, as a generality, the physes at the end of long bones contribute known average lengths in percentage of total bone growth and percentage contributions to the total length between two physes at either end of a long bone. This information has come from observations of longitudinal growth by a number of authors.1113,64,71,102 Knowledge of this information is paramount for the surgeon managing physeal injuries to long bones. Figure 7-5 outlines the generally accepted percentage of longitudinal growth contribution of pairs of physes for each long bone in the upper and lower extremities. Table 7-1 outlines the average amount of growth in millimeters per year of skeletal growth contributed by the same physes mentioned above. These are estimations only, and growth tables should be consulted when more specific information is required.12,13,64,71,102 
Figure 7-5
 
Approximate percentage of longitudinal growth provided by the proximal and distal physes for each long bone in the upper (A) and lower (B) extremities.
Approximate percentage of longitudinal growth provided by the proximal and distal physes for each long bone in the upper (A) and lower (B) extremities.
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Figure 7-5
Approximate percentage of longitudinal growth provided by the proximal and distal physes for each long bone in the upper (A) and lower (B) extremities.
Approximate percentage of longitudinal growth provided by the proximal and distal physes for each long bone in the upper (A) and lower (B) extremities.
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Table 7-1
Average Growth per Year (in mm) of Specific Physes of the Upper and Lower Extremitiesa
Location Average Growth (mm/y)
Proximal humerus 7
Distal humerus 2
Proximal radius 1.75
Distal radius 5.25
Proximal ulna 5.5
Distal ulna 1.5
Proximal femur 3.5
Distal femur 9
Proximal tibia 6
Distal tibia 5
Proximal fibula 6.5
Distal fibula 4.5
 

Data from: Arriola F, Forriol F, Canadell J. Histomorphometric study of growth plate subjected to different mechanical conditions (compression, tension and neutralization): An experimental study in lambs. Mechanical growth plate behavior. J Pediatr Orthop B. 2001; 10(4):334–338; Bright RW, Burstein AH, Elmore SM. Epiphyseal-plate cartilage. A biomechanical and histological analysis of failure modes. J Bone Joint Surg Am. 1974; 56(4):688–703; Gomes LS, Volpon JB, Goncalves RP. Traumatic separation of epiphyses. An experimental study in rats. Clin Orthop Relat Res. 1988;236:286–295; Johnston RM, James WW. Fractures through human growth plates. Orthop Trans. 1980; 4(295); Moen CT, Pelker RR. Biomechanical and histological correlations in growth plate failure. J Pediatr Orthop. 1984; 4(2):180–184; Ogden JA. Skeletal growth mechanism injury patterns. J Pediatr Orthop. 1982; 2(4):371–377; Rivas R, Shapiro F. Structural stages in the development of the long bones and epiphyses: A study in the New Zealand white rabbit. J Bone Joint Surg Am. 2002; 84-A(1):85–100; Rudicel S, Pelker RR, Lee KE, et al. Shear fractures through the capital femoral physis of the skeletally immature rabbit. J Pediatr Orthop. 1985; 5(1):27–31; Shapiro F. Epiphyseal growth plate fracture-separation: A pathophysiologic approach. Orthopaedics. 1982; 5:720–736.

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Mechanical Features of the Physis and Patterns of Injury

An understanding of the microscopic characteristics of the physeal zones permits an understanding of the theoretical line of least resistance (and hence fracture) within the physis. The germinal and proliferative zones are characterized by an abundance of extracellular matrix, whereas the hypertrophic and provisional calcification zones are primarily cell hypertrophy, apoptosis, and vascular channels. As a consequence, fracture lines can be predicted to pass through the hypertrophic and provisional calcification zones, a finding that Salter and Harris reported in their experimental investigation in rats.138 Theoretically, Salter–Harris types I and II fractures should involve these zones only, not affecting the germinal and proliferative zones, and thus should be at lower risk for subsequent growth disturbance. However, types III and IV physeal fractures traverse the entire physis, including the germinal and proliferative zones. In addition, displacement between bone fragments containing portions of the physis may occur. Consequently, growth disturbance is more likely from type III or IV injuries. 
Not surprisingly, mechanical and clinical studies of microscopic fracture patterns have demonstrated that fracture lines through the physeal layers are more complex than this simplistic view, and often undulate through the various zones.28,63,80,112,148,159 Smith et al.148 reported a Salter–Harris type I fracture of the distal tibia examined microscopically after associated traumatic lower leg amputation. In this high-energy injury, they found that the fracture line involved all four layers of the physis, in part because of the relatively straight plane of fracture and the undulations of the physis. Bright et al.28 in a study of experimentally induced physeal fractures in immature rats, found that not only was the fracture line usually complex, involving all four layers of the physis, but also that the physis contained a number of horizontal “cracks” separate from the fracture itself. They also observed a statistically significant lower force required to produce a physeal fracture in male and prepubescent animals, which might have clinical relevance to the epidemiologic aspects of physeal fractures (see “Epidemiology”). The rate, direction, and magnitude of force are also factors that contribute to the histologic pattern of physeal fractures. Moen and Pelker,112 in an experimental study in calves, found that compression forces produced fractures in the zone of provisional calcification and metaphysis, shear caused fractures in the proliferative and hypertrophic zones, and torque produced fracture lines involving all four layers of the physis. Finally, the energy of injury is a factor in the extent of physeal injury. Distal femoral physeal fractures are a good example of the overriding significance of the energy of injury in potential for subsequent growth disturbance. High-energy mechanisms of injury are frequent in this region, and the risk of subsequent growth disturbance is high.99,134 
Our current understanding of how a bone bridge forms following a physeal injury is limited. The experimental studies show a sequence of inflammatory, fibrogenic, and osteogenic responses in the time course of bone bridge formation following a drill hole injury to the proximal tibial physis in a rat model.165 More in-depth study using microarray analysis showed that several molecular pathways including those involved with skeletal development, osteoblast differentiation, BMP signaling, and Wnt signaling are involved in the bone bridge formation.100 A better understanding of mechanisms involved with the bone bridge formation may lead to new treatments that can prevent this complication. 

Physeal Injuries

Etiology of Physeal Injuries

Physes can be injured in many ways, both obvious and subtle. Obviously, the most frequent mechanism of injury is fracture. Most commonly, physeal injury is direct, with a fracture involving the physis itself. Occasionally, physeal injury from trauma is associated with a fracture else wherein the limb segment, either as a result of ischemia125 or perhaps compression1,10,25,76,107,113,157 (see discussion of Salter–Harris type V physeal fractures below). Other mechanisms of injuries to the physes include infection,19,23,91,123 disruption by tumor, cysts,150 and tumor-like disorders, vascular insult,125 repetitive stress,7,26,39,40,98,168 irradiation,34,136 and other rare etiologies.18,32,38,141,168 

Infection

Long bone osteomyelitis or septic arthritis (particularly of the shoulder, hip, and knee) can cause physeal damage resulting in either physeal growth disturbance or frank growth arrest.14,19,23,52,65,78,88,91,123 These septic injuries may be further complicated by joint disruption resulting from associated epiphyseal destruction, articular cartilage damage, and capsular adhesions, particularly in the hip and shoulder. 
Multifocal septic arrests can produce significant deformity requiring multiple surgical procedures. The most common causes are fulminant neonatal sepsis, particularly in premature infants or those with neonatal sepsis associated with maternal diabetes, and multiple septic arrests associated with meningococcemia (Fig. 7-6). In the latter case, physeal damage may also result from the cardiovascular collapse and disseminated intravascular coagulation known as purpura fulminans.14,65,78,88 
Figure 7-6
Standing anteroposterior lower extremity radiograph of a 12-year-old boy with multifocal physeal disturbance from purpura fulminans associated with meningococcemia.
 
Radiograph abnormalities are present in the left proximal femur; both distal femoral epiphyses, including partial arrest of the left distal femoral physis; and both distal tibial epiphyses. The patient also has digital amputations and extensive soft tissue scarring resulting from this septic event.
Radiograph abnormalities are present in the left proximal femur; both distal femoral epiphyses, including partial arrest of the left distal femoral physis; and both distal tibial epiphyses. The patient also has digital amputations and extensive soft tissue scarring resulting from this septic event.
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Figure 7-6
Standing anteroposterior lower extremity radiograph of a 12-year-old boy with multifocal physeal disturbance from purpura fulminans associated with meningococcemia.
Radiograph abnormalities are present in the left proximal femur; both distal femoral epiphyses, including partial arrest of the left distal femoral physis; and both distal tibial epiphyses. The patient also has digital amputations and extensive soft tissue scarring resulting from this septic event.
Radiograph abnormalities are present in the left proximal femur; both distal femoral epiphyses, including partial arrest of the left distal femoral physis; and both distal tibial epiphyses. The patient also has digital amputations and extensive soft tissue scarring resulting from this septic event.
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Tumor

Both malignant and benign tumors and tumor-like disorders can disrupt normal physeal architecture, resulting in direct physeal destruction. In the case of malignant tumors, the extent of growth lost as the result of local irradiation or limb salvage surgery must be taken into consideration in planning and recommending the therapeutic reconstruction to be undertaken. 
Benign tumors and tumor-like conditions can result in destruction of all or part of a physis. Examples include enchondromata, either isolated or multiple (Ollier disease) (Fig. 7-7), and unicameral bone cysts.150 Growth disturbance as a consequence of physeal damage from these disorders generally cannot be corrected by surgical physeal arrest resection (see “Physeal Arrests”), and other treatment strategies must be adopted as clinically indicated. 
Figure 7-7
Valgus deformity of the distal femur associated with the presence of an enchondroma of the distal lateral femur involving the lateral physis.
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Vascular Insult

Known vascular insult is a rare cause of physeal injury.125 Partial or complete growth arrests can occur from a pure vascular injury to an extremity (Fig. 7-8). Unrecognized vascular insult may represent the mechanism of subsequent growth disturbance after an injury in an adjacent part of a limb and may play a role in Salter–Harris type V injuries; the most common location for this is the tibial tubercle after femoral shaft or distal femoral physeal fractures. In addition, ischemia may be the cause of physeal damage associated with purpura fulminans.14,65,78,88 
Figure 7-8
Physeal injury from presumed vascular insult.
 
A: The patient's leg was caught under heavy pipes rolling off a rack, resulting in stripping of the soft tissues from the distal thigh, open comminuted fracture of the distal femur, and popliteal artery injury. B: In follow-up, after arterial and soft tissue reconstruction, the patient has physeal growth arrests of the distal femur and proximal tibia. The mechanism of injury to the proximal tibial physis was presumed to be vascular because of the associated femoral artery injury.
A: The patient's leg was caught under heavy pipes rolling off a rack, resulting in stripping of the soft tissues from the distal thigh, open comminuted fracture of the distal femur, and popliteal artery injury. B: In follow-up, after arterial and soft tissue reconstruction, the patient has physeal growth arrests of the distal femur and proximal tibia. The mechanism of injury to the proximal tibial physis was presumed to be vascular because of the associated femoral artery injury.
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Figure 7-8
Physeal injury from presumed vascular insult.
A: The patient's leg was caught under heavy pipes rolling off a rack, resulting in stripping of the soft tissues from the distal thigh, open comminuted fracture of the distal femur, and popliteal artery injury. B: In follow-up, after arterial and soft tissue reconstruction, the patient has physeal growth arrests of the distal femur and proximal tibia. The mechanism of injury to the proximal tibial physis was presumed to be vascular because of the associated femoral artery injury.
A: The patient's leg was caught under heavy pipes rolling off a rack, resulting in stripping of the soft tissues from the distal thigh, open comminuted fracture of the distal femur, and popliteal artery injury. B: In follow-up, after arterial and soft tissue reconstruction, the patient has physeal growth arrests of the distal femur and proximal tibia. The mechanism of injury to the proximal tibial physis was presumed to be vascular because of the associated femoral artery injury.
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Repetitive Stress

Repetitious physical activities in skeletally immature individuals can result in physeal stress–fracture equivalents.7,39,40 The most common location for such injuries is in the distal radius or ulna, as seen in competitive gymnasts (Fig. 7-9); the proximal tibia, as in running and kicking sports such as soccer (Fig. 7-10); and the proximal humerus, as in baseball pitchers.39 These injuries should be managed by rest, judicious resumption of activities, and longitudinal observation to monitor for potential physeal growth disturbance. 
Figure 7-9
Stress injury of the distal radius and ulna in both wrists of a competitive gymnast.
 
There was no history of specific injury. The wrists were tender to touch. Note distal radial and ulnar physeal widening and irregularity.
There was no history of specific injury. The wrists were tender to touch. Note distal radial and ulnar physeal widening and irregularity.
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Figure 7-9
Stress injury of the distal radius and ulna in both wrists of a competitive gymnast.
There was no history of specific injury. The wrists were tender to touch. Note distal radial and ulnar physeal widening and irregularity.
There was no history of specific injury. The wrists were tender to touch. Note distal radial and ulnar physeal widening and irregularity.
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Figure 7-10
Stress injury of the proximal tibia in an elite soccer player.
 
A: Anteroposterior radiograph film demonstrates subtle proximal tibial physeal widening. B: Lateral radiograph shows widening, a metaphyseal Thurston–Holland fragment, and some posterior displacement of the proximal epiphysis. C: Significant radiograph improvement noted after discontinuing athletic activities for 3 months.
A: Anteroposterior radiograph film demonstrates subtle proximal tibial physeal widening. B: Lateral radiograph shows widening, a metaphyseal Thurston–Holland fragment, and some posterior displacement of the proximal epiphysis. C: Significant radiograph improvement noted after discontinuing athletic activities for 3 months.
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Figure 7-10
Stress injury of the proximal tibia in an elite soccer player.
A: Anteroposterior radiograph film demonstrates subtle proximal tibial physeal widening. B: Lateral radiograph shows widening, a metaphyseal Thurston–Holland fragment, and some posterior displacement of the proximal epiphysis. C: Significant radiograph improvement noted after discontinuing athletic activities for 3 months.
A: Anteroposterior radiograph film demonstrates subtle proximal tibial physeal widening. B: Lateral radiograph shows widening, a metaphyseal Thurston–Holland fragment, and some posterior displacement of the proximal epiphysis. C: Significant radiograph improvement noted after discontinuing athletic activities for 3 months.
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Miscellaneous (Irradiation, Thermal Injury, Electrical, Unrecognized)

Rare causes of physeal injury, usually recognized from consequent growth disturbance, include irradiation (Fig. 7-11)34,136; thermal injury, especially phalangeal physeal injury from frostbite (Fig. 7-12)32,38; burns; and electrical injuries. A recent report noted progressive genu valgum associated with obesity and theorized that repetitive microtrauma superimposed on genetic factors might play a role in growth disturbance.168 On other rare occasions, physeal growth disturbance noted on clinical findings and radiographs has no identifiable cause. Presumably, such events represent unrecognized trauma, infection, or vascular insult involving the physis. 
Figure 7-11
Proximal tibial physeal growth disturbance with angular deformity after irradiation for Ewing sarcoma.
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Figure 7-12
Premature closure of the distal phalangeal physes after a frostbite injury to the digits.
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Historical Review of Physeal Fractures

Physeal fractures have been recognized as unique since ancient times. Hippocrates is credited with the first written account of this injury. Poland (see “Classification of Physeal Fractures”) reviewed accounts of physeal injuries in his 1898 book, Traumatic Separation of the Epiphysis.132 Poland is also credited with the first classification of the patterns of physeal fracture, and the publication of his text closely followed Roentgen's discovery of radiographs in 1895. 

Classification of Physeal Fractures

Poland132 proposed the first classification of physeal fractures in 1898. Modifications to Poland's original scheme have been proposed by a number of authors,25,46,49,101,117,119,126,127,130,138 including Aitken,4 Salter and Harris,138 Ogden et al.119,107 and Peterson.126,127 Classifications of physeal fractures are important because they alert the practitioner to potentially subtle radiographic fracture patterns, can be of prognostic significance with respect to growth disturbance potential, and guide general treatment principles based on that risk and associated joint disruption. To some extent, fracture pattern provides some insight into mechanism of injury and the extent of potential physeal microscopic injury (“Normal Physeal Anatomy” and “Mechanical Features of the Physis and Patterns of Injury”). 
Currently, the Salter–Harris classification, first published in 1963,138 is firmly entrenched in the literature and most orthopedists' minds. Therefore, evolution and specifics of the nature of physeal fractures of the various classification schemes are discussed relative to the Salter–Harris classification. The reader also should be aware of some deficiencies in that classification, as pointed out by Peterson.126128 

Poland Classification of Physeal Fractures

Poland's classification, published in 1898,132 consisted of four types of physeal fractures (Fig. 7-13). Types I, II, and III were the foundation of the Salter–Harris classification, as described below. Poland's type IV fracture was effectively a T-condylar fracture of the epiphysis and physis. 
Figure 7-13
Poland classification of physeal fractures compared to the Salter–Harris classification.
 
Poland type I: Epiphyseal separation without metaphyseal fragment, or extension into the epiphysis. Poland type II: Physeal fracture line extends into the metaphysis. Poland type III: Fracture extends from the articular surface to the physis and continues peripherally through the physis. Poland type IV: T-condylar fracture of the epiphysis and physis.
Poland type I: Epiphyseal separation without metaphyseal fragment, or extension into the epiphysis. Poland type II: Physeal fracture line extends into the metaphysis. Poland type III: Fracture extends from the articular surface to the physis and continues peripherally through the physis. Poland type IV: T-condylar fracture of the epiphysis and physis.
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Figure 7-13
Poland classification of physeal fractures compared to the Salter–Harris classification.
Poland type I: Epiphyseal separation without metaphyseal fragment, or extension into the epiphysis. Poland type II: Physeal fracture line extends into the metaphysis. Poland type III: Fracture extends from the articular surface to the physis and continues peripherally through the physis. Poland type IV: T-condylar fracture of the epiphysis and physis.
Poland type I: Epiphyseal separation without metaphyseal fragment, or extension into the epiphysis. Poland type II: Physeal fracture line extends into the metaphysis. Poland type III: Fracture extends from the articular surface to the physis and continues peripherally through the physis. Poland type IV: T-condylar fracture of the epiphysis and physis.
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Aitken Classification of Physeal Fractures

Aitken4 in 1936 included three patterns of physeal fracture in his classification (Fig. 7-14). His type I corresponded to Poland and Salter–Harris type II fractures, his type II to Poland and Salter–Harris type III fractures, and his type III was an intra-articular transphyseal metaphyseal–epiphyseal fracture equivalent to a Salter–Harris type IV fracture. 
Figure 7-14
Aitken classification of physeal fractures: Types I, II, and III.
 
Type III is equivalent of Salter–Harris type IV.
Type III is equivalent of Salter–Harris type IV.
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Figure 7-14
Aitken classification of physeal fractures: Types I, II, and III.
Type III is equivalent of Salter–Harris type IV.
Type III is equivalent of Salter–Harris type IV.
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Salter–Harris Classification of Physeal Fractures

Salter and Harris published their commonly used five-part classification of physeal injuries in 1963.138 The first four types were adopted from Poland (types I, II, and III) and Aitken (Aitken type III became Salter–Harris type IV) (Fig. 7-15). Salter and Harris added a fifth type, which they postulated was an unrecognized compression injury characterized by normal radiographs and late physeal closure. Peterson and Burkhart challenged the existence of true type V injuries,128 but other authors have subsequently documented its existence in some form.1,10,17,25,74,76,86,128,157 Because we believe that delayed physeal closure can occur after some occult injuries, we have chosen to retain this type of injury in our preferred classification scheme. 
Figure 7-15
Salter–Harris classification of physeal fractures.
 
In Salter–Harris type I fractures, the fracture line is entirely within the physis, referred to by Poland as type I. In Salter–Harris type II fractures, the fracture line extends from the physis into the metaphysis; described by Poland as type II and Aitken as type I. In Salter–Harris type III fractures, the fracture enters the epiphysis from the physis and almost always exits the articular surface. Poland described this injury as type III and Aitken as type II. In Salter–Harris type IV, the fracture extends across the physis from the articular surface and epiphysis, to exit in the margin of the metaphysis. Aitken described this as a type III injury in his classification. Salter–Harris type V fractures were described by Salter and Harris as a crush injury to the physis with initially normal radiographs with late identification of premature physeal closure.
In Salter–Harris type I fractures, the fracture line is entirely within the physis, referred to by Poland as type I. In Salter–Harris type II fractures, the fracture line extends from the physis into the metaphysis; described by Poland as type II and Aitken as type I. In Salter–Harris type III fractures, the fracture enters the epiphysis from the physis and almost always exits the articular surface. Poland described this injury as type III and Aitken as type II. In Salter–Harris type IV, the fracture extends across the physis from the articular surface and epiphysis, to exit in the margin of the metaphysis. Aitken described this as a type III injury in his classification. Salter–Harris type V fractures were described by Salter and Harris as a crush injury to the physis with initially normal radiographs with late identification of premature physeal closure.
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Figure 7-15
Salter–Harris classification of physeal fractures.
In Salter–Harris type I fractures, the fracture line is entirely within the physis, referred to by Poland as type I. In Salter–Harris type II fractures, the fracture line extends from the physis into the metaphysis; described by Poland as type II and Aitken as type I. In Salter–Harris type III fractures, the fracture enters the epiphysis from the physis and almost always exits the articular surface. Poland described this injury as type III and Aitken as type II. In Salter–Harris type IV, the fracture extends across the physis from the articular surface and epiphysis, to exit in the margin of the metaphysis. Aitken described this as a type III injury in his classification. Salter–Harris type V fractures were described by Salter and Harris as a crush injury to the physis with initially normal radiographs with late identification of premature physeal closure.
In Salter–Harris type I fractures, the fracture line is entirely within the physis, referred to by Poland as type I. In Salter–Harris type II fractures, the fracture line extends from the physis into the metaphysis; described by Poland as type II and Aitken as type I. In Salter–Harris type III fractures, the fracture enters the epiphysis from the physis and almost always exits the articular surface. Poland described this injury as type III and Aitken as type II. In Salter–Harris type IV, the fracture extends across the physis from the articular surface and epiphysis, to exit in the margin of the metaphysis. Aitken described this as a type III injury in his classification. Salter–Harris type V fractures were described by Salter and Harris as a crush injury to the physis with initially normal radiographs with late identification of premature physeal closure.
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Type I
Salter–Harris type I injuries are characterized by a transphyseal plane of injury, with no bony fracture line through either the metaphysis or the epiphysis. Radiographs of undisplaced type I physeal fractures, therefore, are normal except for associated soft tissue swelling, making careful patient examination particularly important in this injury. In the Olmstead County Survey of physeal fractures,129 type I fractures occurred most frequently in the phalanges, metacarpals, distal tibia, and distal ulna. Epiphyseal separations in infants occur most commonly in the proximal humerus, distal humerus, and proximal femur. If an urgency to make the diagnosis is deemed necessary for patients suspected of having a type I injury, further imaging by ultrasound, magnetic resonance imaging (MRI),36,44,79,130,147 or intraoperative arthrography may be helpful.6,67,105 Stress radiographs to document displacement are generally unnecessary and probably unwise. Ultrasound is particularly helpful for assessing epiphyseal separations in infants (especially in the proximal femur and elbow regions) without the need for sedation, anesthetic, or invasive procedure.30,48,50,73,140 
The fracture line of type I injuries is usually in the zone of hypertrophy of the physis, as the path of least resistance during the propagation of the injury (see “Normal Physeal Anatomy”) (Fig. 7-16). As a consequence, in theory, the essential resting and proliferative zones are relatively spared, and, assuming that there is no vascular insult to these zones as a consequence of the injury, subsequent growth disturbance is relatively uncommon. As discussed above, however, studies have shown this to be a simplistic view of the fracture line through a physis, and that, because of uneven loading and macroscopic undulations in the physis, any zone of the physis can be affected by the fracture line.27,80,112,137,141,148 
Figure 7-16
Scheme of theoretic fracture plane of Salter–Harris type I fractures.
 
Because the hypertrophic zone is the weakest zone structurally, separation should occur at this level. Experimental and clinical studies have confirmed that the fracture plane is more complex than this concept and frequently involves other physeal zones as well.
Because the hypertrophic zone is the weakest zone structurally, separation should occur at this level. Experimental and clinical studies have confirmed that the fracture plane is more complex than this concept and frequently involves other physeal zones as well.
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Figure 7-16
Scheme of theoretic fracture plane of Salter–Harris type I fractures.
Because the hypertrophic zone is the weakest zone structurally, separation should occur at this level. Experimental and clinical studies have confirmed that the fracture plane is more complex than this concept and frequently involves other physeal zones as well.
Because the hypertrophic zone is the weakest zone structurally, separation should occur at this level. Experimental and clinical studies have confirmed that the fracture plane is more complex than this concept and frequently involves other physeal zones as well.
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Because the articular surface and, at least in theory, the germinal and proliferative layers of the physis are not displaced, the general principles of fracture management are to secure a gentle and adequate reduction of the epiphysis on the metaphysis and stabilize the fragments as needed. 
Type II
Type II injuries have physeal and metaphyseal components; the fracture line extends from the physeal margin peripherally across a variable portion of the physis and exits into the metaphysis at the opposite end of the fracture (Fig. 7-17). The epiphyseal fragment thus comprises all of the epiphysis and some portion of the peripheral metaphysis (the Thurston–Holland fragment or sign). The physeal portion of this fracture has microscopic characteristics similar to those of type I injuries, but the fracture line exits the physis to enter the metaphysis (i.e., away from the germinal and proliferative layers) at one margin. Similar to type I injuries, these fractures should have a limited propensity to subsequent growth disturbance as a consequence of direct physeal injury. However, the metaphyseal “spike” of the diaphyseal/metaphyseal fragment may be driven into the physis of the epiphyseal fragment, which can damage the physis (Fig. 7-18). Similar to type I injuries, the articular surface is not affected and the general principles of fracture management are effectively the same. 
Figure 7-17
Fracture plane of Salter–Harris type II fractures.
 
The fracture extends from the physis into the periphery of the metaphysis.
The fracture extends from the physis into the periphery of the metaphysis.
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Figure 7-17
Fracture plane of Salter–Harris type II fractures.
The fracture extends from the physis into the periphery of the metaphysis.
The fracture extends from the physis into the periphery of the metaphysis.
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Figure 7-18
Potential mechanism of physeal arrest development after Salter–Harris type II fracture of the distal radius.
 
A: Dorsally displaced type II fracture of the distal radius. Note the evidence of impaction of the epiphyseal fragment (with the physis) by the dorsal margin of the proximal fragment metaphysis. B: One year later, there is radiographic evidence of physeal arrest formation in the distal radial physis.
A: Dorsally displaced type II fracture of the distal radius. Note the evidence of impaction of the epiphyseal fragment (with the physis) by the dorsal margin of the proximal fragment metaphysis. B: One year later, there is radiographic evidence of physeal arrest formation in the distal radial physis.
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Figure 7-18
Potential mechanism of physeal arrest development after Salter–Harris type II fracture of the distal radius.
A: Dorsally displaced type II fracture of the distal radius. Note the evidence of impaction of the epiphyseal fragment (with the physis) by the dorsal margin of the proximal fragment metaphysis. B: One year later, there is radiographic evidence of physeal arrest formation in the distal radial physis.
A: Dorsally displaced type II fracture of the distal radius. Note the evidence of impaction of the epiphyseal fragment (with the physis) by the dorsal margin of the proximal fragment metaphysis. B: One year later, there is radiographic evidence of physeal arrest formation in the distal radial physis.
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Type III
Salter–Harris type III fractures begin in the epiphysis (with only rare exception) as a fracture through the articular surface and extend vertically toward the physis. The fracture then courses peripherally through the physis (Fig. 7-19). There are two fracture fragments: A small fragment consisting of a portion of the epiphysis and physis, and a large fragment consisting the remaining epiphysis and long bone. This fracture pattern is important for two main reasons: The articular surface is involved (Fig. 7-20) and the fracture line involves the germinal and proliferative layers of the physis. In addition, type III injuries are often associated with high-energy or compression mechanisms of injury, which imply greater potential disruption of the physis and higher risk of subsequent growth disturbance. Anatomic reduction (usually open) and stabilization are required to restore the articular surface and to minimize the potential for growth disturbance. 
Figure 7-19
Scheme of fracture plane in Salter–Harris type III fractures.
 
The fracture plane extends from the physis into the epiphysis and articular surface. “Extra-articular” type III fractures in which the articular surface is intact have been reported but are quite rare.
The fracture plane extends from the physis into the epiphysis and articular surface. “Extra-articular” type III fractures in which the articular surface is intact have been reported but are quite rare.
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Figure 7-19
Scheme of fracture plane in Salter–Harris type III fractures.
The fracture plane extends from the physis into the epiphysis and articular surface. “Extra-articular” type III fractures in which the articular surface is intact have been reported but are quite rare.
The fracture plane extends from the physis into the epiphysis and articular surface. “Extra-articular” type III fractures in which the articular surface is intact have been reported but are quite rare.
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Figure 7-20
 
A: Salter–Harris type III fracture of the distal femur. B: Fixation with cannulated screws.
A: Salter–Harris type III fracture of the distal femur. B: Fixation with cannulated screws.
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Figure 7-20
A: Salter–Harris type III fracture of the distal femur. B: Fixation with cannulated screws.
A: Salter–Harris type III fracture of the distal femur. B: Fixation with cannulated screws.
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On occasion, particularly in the distal femur and the distal humerus, high-energy injuries produce either a T-condylar or other complex pattern of injury, with at least three fragments, resulting in a combination of physeal and epiphyseal injuries (Fig. 7-21). 
Figure 7-21
Complex fracture of the distal femur.
 
There is a Salter–Harris type II fracture of the distal femoral physis. In addition, there is an additional coronal plane epiphyseal fracture of the major portion of the lateral femoral condyle, not involving the physis, which was not recognized at the time of initial treatment. The type II component was treated by closed reduction and cross-pinning. The epiphyseal fracture was treated separately and subsequently by open reduction and headless screw fixation. A: Initial anteroposterior radiograph showing what appears to be simple Salter–Harris type II fracture of the distal femur. B: Lateral radiograph after reduction appears acceptable; however, careful review demonstrates the coronal plane, intra-articular fracture of the lateral condyle. C: CT scan demonstrates the epiphyseal fracture of the lateral femoral condyle. D, E: Radiograph appearance after healing of the fractures. Patient was asymptomatic and recovered full knee motion. In follow-up, the patient developed symmetric distal physeal closure not requiring further treatment.
There is a Salter–Harris type II fracture of the distal femoral physis. In addition, there is an additional coronal plane epiphyseal fracture of the major portion of the lateral femoral condyle, not involving the physis, which was not recognized at the time of initial treatment. The type II component was treated by closed reduction and cross-pinning. The epiphyseal fracture was treated separately and subsequently by open reduction and headless screw fixation. A: Initial anteroposterior radiograph showing what appears to be simple Salter–Harris type II fracture of the distal femur. B: Lateral radiograph after reduction appears acceptable; however, careful review demonstrates the coronal plane, intra-articular fracture of the lateral condyle. C: CT scan demonstrates the epiphyseal fracture of the lateral femoral condyle. D, E: Radiograph appearance after healing of the fractures. Patient was asymptomatic and recovered full knee motion. In follow-up, the patient developed symmetric distal physeal closure not requiring further treatment.
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Figure 7-21
Complex fracture of the distal femur.
There is a Salter–Harris type II fracture of the distal femoral physis. In addition, there is an additional coronal plane epiphyseal fracture of the major portion of the lateral femoral condyle, not involving the physis, which was not recognized at the time of initial treatment. The type II component was treated by closed reduction and cross-pinning. The epiphyseal fracture was treated separately and subsequently by open reduction and headless screw fixation. A: Initial anteroposterior radiograph showing what appears to be simple Salter–Harris type II fracture of the distal femur. B: Lateral radiograph after reduction appears acceptable; however, careful review demonstrates the coronal plane, intra-articular fracture of the lateral condyle. C: CT scan demonstrates the epiphyseal fracture of the lateral femoral condyle. D, E: Radiograph appearance after healing of the fractures. Patient was asymptomatic and recovered full knee motion. In follow-up, the patient developed symmetric distal physeal closure not requiring further treatment.
There is a Salter–Harris type II fracture of the distal femoral physis. In addition, there is an additional coronal plane epiphyseal fracture of the major portion of the lateral femoral condyle, not involving the physis, which was not recognized at the time of initial treatment. The type II component was treated by closed reduction and cross-pinning. The epiphyseal fracture was treated separately and subsequently by open reduction and headless screw fixation. A: Initial anteroposterior radiograph showing what appears to be simple Salter–Harris type II fracture of the distal femur. B: Lateral radiograph after reduction appears acceptable; however, careful review demonstrates the coronal plane, intra-articular fracture of the lateral condyle. C: CT scan demonstrates the epiphyseal fracture of the lateral femoral condyle. D, E: Radiograph appearance after healing of the fractures. Patient was asymptomatic and recovered full knee motion. In follow-up, the patient developed symmetric distal physeal closure not requiring further treatment.
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Type IV
Type IV fractures are effectively vertical shear fractures, extending from the articular surface to the metaphysis (Fig. 7-22A). These fractures are important because they disrupt the articular surface, violate all the physeal layers in crossing from the epiphysis to the metaphysis, and, with displacement, may result in metaphyseal–epiphyseal cross union (Fig. 7-22B).41,62 The latter occurrence almost invariably results in subsequent growth disturbance. This fracture pattern is frequent around the medial malleolus, but may occur in other epiphyses. Lateral condylar fractures of the distal humerus and intra-articular two-part triplane fractures of the distal tibia may be thought of as complex Salter–Harris type IV fractures. 
Figure 7-22
Scheme of the Salter–Harris type IV fracture.
 
A: The fracture line extends across the physis from the epiphysis and articular surface into the peripheral metaphysis. B: Displacement of the fragments can lead to horizontal apposition (and cross union) of the epiphyseal and metaphyseal bones.
A: The fracture line extends across the physis from the epiphysis and articular surface into the peripheral metaphysis. B: Displacement of the fragments can lead to horizontal apposition (and cross union) of the epiphyseal and metaphyseal bones.
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Figure 7-22
Scheme of the Salter–Harris type IV fracture.
A: The fracture line extends across the physis from the epiphysis and articular surface into the peripheral metaphysis. B: Displacement of the fragments can lead to horizontal apposition (and cross union) of the epiphyseal and metaphyseal bones.
A: The fracture line extends across the physis from the epiphysis and articular surface into the peripheral metaphysis. B: Displacement of the fragments can lead to horizontal apposition (and cross union) of the epiphyseal and metaphyseal bones.
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General treatment principles include obtaining anatomic reduction and adequate stabilization to restore the articular surface and prevent metaphyseal–epiphyseal cross union. 
Type V
The type V fracture described by Salter and Harris was not described by Poland or Aitken. Salter and Harris postulated that type V fractures represented unrecognized compression injuries with normal initial radiographs that later produced premature physeal closure. The existence of true type V injuries was questioned by Peterson128 and subsequently became a subject of debate.1,10,17,25,74,76,86,157 We believe that delayed physeal closure clearly occurs. The most common example of such an injury is closure of the tibial tubercle, often with the development of recurvatum deformity of the proximal tibia, after fractures of the femur or distal femoral epiphysis (Fig. 7-23).25,74,76 Although the mechanism of such injuries may be unclear (perhaps vascular rather than compression trauma), the traditionally held view that such injuries occurred as a result of inadvertent direct injury during the insertion of proximal tibial skeletal traction pins has been unequivocally discounted in some cases.25,74,76 Other locations and case reports of late physeal closure after extremity injury and apparently normal initial radiographs exist in the literature.1,10,17,19,111,157 By definition, this pattern of injury is unrecognized on initial radiographs. Undoubtedly, more sophisticated imaging of injured extremities (such as with MRI) will identify physeal injuries in the presence of normal plain radiographs (Fig. 7-24). Although the mechanism of injury in type V injuries may be in dispute, in our opinion, the existence of such injuries is not. 
Figure 7-23
Posttraumatic closure of the anterior proximal tibial physis after displaced Salter–Harris type II fracture of the distal femoral physis.
 
A: Lateral radiographs after reduction. No injury to the proximal tibia was noted at the time of treatment of the distal femoral injury. B: At follow-up, distal femoral physeal growth disturbance with flexion deformity is apparent. C: At skeletal maturity, proximal tibial extension deformity with sclerosis of the tibial tubercle area is evident, suggestive of arrest in this area. The patient has undergone a distal femoral extension osteotomy.
A: Lateral radiographs after reduction. No injury to the proximal tibia was noted at the time of treatment of the distal femoral injury. B: At follow-up, distal femoral physeal growth disturbance with flexion deformity is apparent. C: At skeletal maturity, proximal tibial extension deformity with sclerosis of the tibial tubercle area is evident, suggestive of arrest in this area. The patient has undergone a distal femoral extension osteotomy.
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Figure 7-23
Posttraumatic closure of the anterior proximal tibial physis after displaced Salter–Harris type II fracture of the distal femoral physis.
A: Lateral radiographs after reduction. No injury to the proximal tibia was noted at the time of treatment of the distal femoral injury. B: At follow-up, distal femoral physeal growth disturbance with flexion deformity is apparent. C: At skeletal maturity, proximal tibial extension deformity with sclerosis of the tibial tubercle area is evident, suggestive of arrest in this area. The patient has undergone a distal femoral extension osteotomy.
A: Lateral radiographs after reduction. No injury to the proximal tibia was noted at the time of treatment of the distal femoral injury. B: At follow-up, distal femoral physeal growth disturbance with flexion deformity is apparent. C: At skeletal maturity, proximal tibial extension deformity with sclerosis of the tibial tubercle area is evident, suggestive of arrest in this area. The patient has undergone a distal femoral extension osteotomy.
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Figure 7-24
MRI of patient after injury with normal radiographs.
 
MRI clearly documents the presence of a Salter–Harris type II fracture of the distal femur.
MRI clearly documents the presence of a Salter–Harris type II fracture of the distal femur.
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Figure 7-24
MRI of patient after injury with normal radiographs.
MRI clearly documents the presence of a Salter–Harris type II fracture of the distal femur.
MRI clearly documents the presence of a Salter–Harris type II fracture of the distal femur.
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Peterson Classification of Physeal Fractures

In an epidemiologic study of physeal injuries, Peterson et al.128 identified several deficiencies of the Salter–Harris classification and subsequently developed a new classification of physeal fractures (Fig. 7-25). They were not able to identify any Salter–Harris type V injuries caused by compression in this epidemiologic study, challenged their existence, and excluded that type from the classification. This classification retained Salter–Harris types I to IV as Peterson types II, III, IV, and V and added two new types.126,127 It is important to be cognizant of the two new patterns that Peterson et al. described, because they are clinically relevant. 
Figure 7-25
Peterson classification of physeal fractures.
 
Type I is a fracture of the metaphysis extending to the physis. Types II to V are the equivalents of Salter–Harris types I, II, III, and IV, respectively. Peterson type VI is epiphyseal (and usually articular surface) loss. Lawnmower injuries are a frequent mechanism for type VI injuries (see text for further discussion).
Type I is a fracture of the metaphysis extending to the physis. Types II to V are the equivalents of Salter–Harris types I, II, III, and IV, respectively. Peterson type VI is epiphyseal (and usually articular surface) loss. Lawnmower injuries are a frequent mechanism for type VI injuries (see text for further discussion).
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Figure 7-25
Peterson classification of physeal fractures.
Type I is a fracture of the metaphysis extending to the physis. Types II to V are the equivalents of Salter–Harris types I, II, III, and IV, respectively. Peterson type VI is epiphyseal (and usually articular surface) loss. Lawnmower injuries are a frequent mechanism for type VI injuries (see text for further discussion).
Type I is a fracture of the metaphysis extending to the physis. Types II to V are the equivalents of Salter–Harris types I, II, III, and IV, respectively. Peterson type VI is epiphyseal (and usually articular surface) loss. Lawnmower injuries are a frequent mechanism for type VI injuries (see text for further discussion).
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Peterson's type I is a transverse metaphyseal fracture with a longitudinal extension to the physis (Fig. 7-26). This pattern of injury is subclassified into four types, based on the extent of metaphyseal comminution and fracture pattern. 
Figure 7-26
Peterson type I injury of the distal radius.
 
These injuries typically have a benign course with respect to subsequent growth disturbance.
These injuries typically have a benign course with respect to subsequent growth disturbance.
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Figure 7-26
Peterson type I injury of the distal radius.
These injuries typically have a benign course with respect to subsequent growth disturbance.
These injuries typically have a benign course with respect to subsequent growth disturbance.
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Peterson's type VI is a partial physeal loss (Fig. 7-27). Unfortunately, this pattern of injury currently is common, largely as a consequence of lawnmower or “road-drag/abrasion” injuries. Soft tissue loss, neurovascular injury, and partial physeal loss (usually including the epiphysis so that articular impairment also results) further complicate this often devastating injury. 
Figure 7-27
Sequelae of a Peterson type VI physeal injury.
 
A: Anteroposterior radiograph of distal femur of a young girl who suffered a Peterson type VI injury. This particular injury was the result of direct abrasion of the distal femur when the unrestrained child was ejected from a car. B: CT scan 1 year after injury demonstrates the development of a peripheral physeal arrest with valgus deformity.
A: Anteroposterior radiograph of distal femur of a young girl who suffered a Peterson type VI injury. This particular injury was the result of direct abrasion of the distal femur when the unrestrained child was ejected from a car. B: CT scan 1 year after injury demonstrates the development of a peripheral physeal arrest with valgus deformity.
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Figure 7-27
Sequelae of a Peterson type VI physeal injury.
A: Anteroposterior radiograph of distal femur of a young girl who suffered a Peterson type VI injury. This particular injury was the result of direct abrasion of the distal femur when the unrestrained child was ejected from a car. B: CT scan 1 year after injury demonstrates the development of a peripheral physeal arrest with valgus deformity.
A: Anteroposterior radiograph of distal femur of a young girl who suffered a Peterson type VI injury. This particular injury was the result of direct abrasion of the distal femur when the unrestrained child was ejected from a car. B: CT scan 1 year after injury demonstrates the development of a peripheral physeal arrest with valgus deformity.
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Author's Preferred Treatment

We believe that the Salter–Harris classification remains an easily recognized and recalled classification scheme embracing most physeal injuries and continue to use it to describe most physeal fracture patterns. It provides generally useful prognostic and treatment guidelines. We encourage the continued recognition of the Salter–Harris type V physeal injury as a delayed, indirect, or occult injury–induced physeal closure, whose mechanism may be compression, other unrecognized direct injury, or vascular insult. We also believe that Peterson types I and VI physeal fractures are not classifiable by the Salter–Harris scheme and refer to them as Peterson types I and VI fractures, respectively. 

Epidemiology of Physeal Fractures

In several population surveys reporting the frequency and distribution of childhood fractures, including physeal injuries,101,111,129,164 20% to 30% of all childhood fractures were physeal injuries. The phalanges represent the most common location of physeal injuries. 
In our opinion, the most useful epidemiologic study of physeal fractures is the Olmstead County Survey.129 This study of the frequency of physeal fractures in a stable population base was performed between 1979 and 1988, in Olmstead County, Minnesota. The most relevant components are summarized in Tables 7-2 and 7-3. During the study period, 951 physeal fractures were identified: 37% of fractures occurred in the finger phalanges, with the next most common site the distal radius; 71% fractures occurred in the upper extremity; 28% in the lower; and 1% in the axial skeleton. Other salient findings of the Olmstead County survey included a 2:1 male-to-female ratio and age-related incidence by gender (peak incidence at age 14 in boys and 11 to 12 in girls) (Fig. 7-28). The Adelaide, Australia, survey by Mizuta et al.111 had similar findings: 30% of physeal fractures were phalangeal, males outnumbered females approximately 2:1, and the prepubertal age groups had the highest relative frequency of physeal fracture. 
 
Table 7-2
Frequency of Physeal Fracture by Location
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Table 7-2
Frequency of Physeal Fracture by Location
Skeletal Site Number Percent
Phalanges (fingers and toes) 411 43.4
Distal radius 170 17.9
Distal tibia 104 11
Distal fibula 68 7.2
Metacarpal 61 6.4
Distal humerus 37 3.9
Distal ulna 27 2.8
Proximal humerus 18 1.9
Distal femur 13 1.4
Metatarsal 13 1.4
Proximal tibia 8 0.8
Proximal radius 6 0.6
Clavicle (medial and lateral) 6 0.6
Proximal ulna 4 0.4
Proximal femur 1 0.1
Proximal fibula 1 0.1
 

Modified from Peterson HA, Madhok R, Benson JT, et al. Physeal fractures: Part I. Epidemiology in Olmsted County, Minnesota, 1979–1988. J Pediatr Orthop. 1994; 14:423–430.

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Table 7-3
Distribution of Physeal Fracture Patterns by Salter–Harris and Peterson Types I and VI Classificationa
Fracture Type Number Percent
Salter–Harris I 126 13.2
Salter–Harris II 510 53.6
Salter–Harris III 104 10.9
Salter–Harris IV 62 6.5
Peterson I 147 15.5
Peterson VI 2 0.2
 

Modified from Peterson HA, Madhok R, Benson JT, et al. Physeal fractures: Part I. Epidemiology in Olmsted County, Minnesota, 1979–1988. J Pediatr Orthop. 1994; 14:423–430.

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Figure 7-28
Relative frequency of physeal fractures by age and sex according to the Olmstead County survey by Peterson et al.
 
Peak incidence age 14 in boys, and 11 to 12 in girls.
 
(From Poland J, ed. Traumatic Separation of the Epiphysis. London: E. Smith and Company; 1898.)
Peak incidence age 14 in boys, and 11 to 12 in girls.
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Figure 7-28
Relative frequency of physeal fractures by age and sex according to the Olmstead County survey by Peterson et al.
Peak incidence age 14 in boys, and 11 to 12 in girls.
(From Poland J, ed. Traumatic Separation of the Epiphysis. London: E. Smith and Company; 1898.)
Peak incidence age 14 in boys, and 11 to 12 in girls.
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Evaluation of Physeal Fractures

Modalities available for the evaluation of physeal injuries include plain radiographs, computed tomography (CT) scans, and MRI scans36,44,60,79,80,130,147 arthrography,6,47,67,105,166 and ultrasound.30,48,50,73,140 Plain radiographs remain the preferred initial modality for the assessment of most physeal injuries. Radiographs should be taken in true orthogonal views and as a default include the joint both above and below the fracture unless clinical examination rules out areas of pathology, that is, a very distal both bone fracture may not need radiographs of the elbow if clinical examination of the elbow is normal. If a physeal injury is suspected, dedicated views centered over the suspected physis should be obtained to decrease parallax and increase detail. Oblique views may be of value in assessing minimally displaced injuries. 
Although plain radiographs provide adequate detail for the assessment and treatment of most physeal injuries, occasionally greater anatomic detail is necessary. CT scans provide excellent definition of bony anatomy, particularly using reconstructed images. They may be helpful in assessing complex or highly comminuted fractures, as well as the articular congruency of minimally displaced fractures (Fig. 7-29). MRI scans are excellent for demonstrating soft tissue lesions and “bone bruises” which may not be seen using standard radiation techniques. 
Figure 7-29
CT scans with or without reconstructed images can be helpful in the assessment of physeal fractures.
 
Coronal (A) and sagittal (B) plane reconstructions of a triplane fracture of the distal tibia.
Coronal (A) and sagittal (B) plane reconstructions of a triplane fracture of the distal tibia.
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Figure 7-29
CT scans with or without reconstructed images can be helpful in the assessment of physeal fractures.
Coronal (A) and sagittal (B) plane reconstructions of a triplane fracture of the distal tibia.
Coronal (A) and sagittal (B) plane reconstructions of a triplane fracture of the distal tibia.
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Arthrography, MRI, and ultrasound have been used to assess the congruency of articular surfaces. Arthrography and MRI may help define the anatomy in young patients with small or no secondary ossification centers in the epiphyses.6,47,67,105,166 Ultrasonography is occasionally useful for diagnostic purposes to identify epiphyseal separation in infants (Fig. 7-30).30,47,48,50,73 
Figure 7-30
Ultrasonography can be useful as a noninvasive investigation confirming intra-articular effusion or epiphyseal separation, particularly in infants.
 
A: Anteroposterior radiograph of a 2-month-old infant with bilateral hip pain and generalized irritability. Septic arthritis is included in the differential diagnosis. B: Ultrasonographic image of the right hip demonstrates a femoral head contained in the acetabulum, without significant hip effusion. C: This ultrasonographic image demonstrates separation of the proximal epiphysis from the femoral metaphysis. The diagnosis is nonaccidental trauma. D: One month later, radiograph demonstrates extensive periosteal reaction bilaterally. E: At 18 months of age, radiograph demonstrates remarkable remodeling, without evidence of physeal growth disturbance or epiphyseal abnormality.
A: Anteroposterior radiograph of a 2-month-old infant with bilateral hip pain and generalized irritability. Septic arthritis is included in the differential diagnosis. B: Ultrasonographic image of the right hip demonstrates a femoral head contained in the acetabulum, without significant hip effusion. C: This ultrasonographic image demonstrates separation of the proximal epiphysis from the femoral metaphysis. The diagnosis is nonaccidental trauma. D: One month later, radiograph demonstrates extensive periosteal reaction bilaterally. E: At 18 months of age, radiograph demonstrates remarkable remodeling, without evidence of physeal growth disturbance or epiphyseal abnormality.
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Figure 7-30
Ultrasonography can be useful as a noninvasive investigation confirming intra-articular effusion or epiphyseal separation, particularly in infants.
A: Anteroposterior radiograph of a 2-month-old infant with bilateral hip pain and generalized irritability. Septic arthritis is included in the differential diagnosis. B: Ultrasonographic image of the right hip demonstrates a femoral head contained in the acetabulum, without significant hip effusion. C: This ultrasonographic image demonstrates separation of the proximal epiphysis from the femoral metaphysis. The diagnosis is nonaccidental trauma. D: One month later, radiograph demonstrates extensive periosteal reaction bilaterally. E: At 18 months of age, radiograph demonstrates remarkable remodeling, without evidence of physeal growth disturbance or epiphyseal abnormality.
A: Anteroposterior radiograph of a 2-month-old infant with bilateral hip pain and generalized irritability. Septic arthritis is included in the differential diagnosis. B: Ultrasonographic image of the right hip demonstrates a femoral head contained in the acetabulum, without significant hip effusion. C: This ultrasonographic image demonstrates separation of the proximal epiphysis from the femoral metaphysis. The diagnosis is nonaccidental trauma. D: One month later, radiograph demonstrates extensive periosteal reaction bilaterally. E: At 18 months of age, radiograph demonstrates remarkable remodeling, without evidence of physeal growth disturbance or epiphyseal abnormality.
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Treatment

The general tenets of physeal fracture management are essentially the same as those for injuries not involving the physis, including radiographs of all areas with abnormal physical findings. Physeal injuries involving neurovascular compromise or impending compartment syndrome should be managed emergently. In most cases, stabilization of the physeal fractures will help facilitate management of the soft tissue injury. 

General Principles of Treatment

In general, fractures in children, including physeal injuries, heal more rapidly than in adults, and they are less likely to experience morbidity or mortality from prolonged immobilization. In addition, children are also often less compliant with postoperative activity restrictions, making cast immobilization a frequently necessary adjunct to therapy. 
Physeal fractures, like all fractures, should be managed in a consistent methodical manner that includes a general assessment and stabilization of the polytraumatized patient, evaluation of the neurovascular and soft tissue status of the traumatized limb; what constitutes an “acceptable” reduction is dictated in part by the fracture pattern and remodeling potential of the fracture. Intra-articular fractures (such as Salter–Harris types III and IV) require anatomic reduction to restore the articular surface and prevent epiphyseal–metaphyseal cross union. Salter–Harris types I and II fractures, particularly those that are the result of low-energy injuries, have minimal risk of growth disturbance (excepting injuries of the distal femur and proximal tibia) and excellent remodeling potential in most patients; in such patients, the surgeon must be cautious not to create physeal injury by excessively forceful or invasive reductions. When performing a closed reduction of physeal fractures the aphorism “90% traction, 10% translation” is useful to minimize iatrogenic injury to the physis which may occur as a physis grinds against a sharp bony metaphysis. 

Complications of Physeal Fractures

Except for the possibility of subsequent growth disturbance, the potential complications of physeal injuries are no different than other traumatic musculoskeletal injuries. Neurovascular compromise and compartment syndrome represent the most serious potential complications.29,122 It is important to remember that, although a high degree of suspicion and diligence may avoid some of these potentially devastating complications, they can occur even with “ideal” management. Infection and soft tissue loss can complicate physeal fracture management, just as they can in other fractures. The one complication unique to physeal injuries is growth disturbance. Most commonly, this “disturbance” is the result of a tethering (physeal bar or arrest) that may produce angular deformity or shortening. However, growth disturbance may occur without an obvious tether or bar and growth acceleration also occurs (Fig. 7-31). Finally, growth disturbance may occur without recognized injury to the physis. 
Figure 7-31
Growth deceleration in the absence of a true physeal arrest.
 
This patient sustained concurrent ipsilateral femoral shaft and Salter–Harris type IV distal femoral epiphyseal fractures. A: Anteroposterior radiograph of the healed femur. Both fractures were treated with internal fixation. B: The patient developed valgus deformity of the distal femur because of asymmetric growth of the distal femoral physis. Note that the distance between the screws on either side of the physis has increased asymmetrically, confirming asymmetric growth rather than cessation of growth laterally. C: The angular deformity was treated with medial distal femoral epiphyseal stapling.
This patient sustained concurrent ipsilateral femoral shaft and Salter–Harris type IV distal femoral epiphyseal fractures. A: Anteroposterior radiograph of the healed femur. Both fractures were treated with internal fixation. B: The patient developed valgus deformity of the distal femur because of asymmetric growth of the distal femoral physis. Note that the distance between the screws on either side of the physis has increased asymmetrically, confirming asymmetric growth rather than cessation of growth laterally. C: The angular deformity was treated with medial distal femoral epiphyseal stapling.
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Figure 7-31
Growth deceleration in the absence of a true physeal arrest.
This patient sustained concurrent ipsilateral femoral shaft and Salter–Harris type IV distal femoral epiphyseal fractures. A: Anteroposterior radiograph of the healed femur. Both fractures were treated with internal fixation. B: The patient developed valgus deformity of the distal femur because of asymmetric growth of the distal femoral physis. Note that the distance between the screws on either side of the physis has increased asymmetrically, confirming asymmetric growth rather than cessation of growth laterally. C: The angular deformity was treated with medial distal femoral epiphyseal stapling.
This patient sustained concurrent ipsilateral femoral shaft and Salter–Harris type IV distal femoral epiphyseal fractures. A: Anteroposterior radiograph of the healed femur. Both fractures were treated with internal fixation. B: The patient developed valgus deformity of the distal femur because of asymmetric growth of the distal femoral physis. Note that the distance between the screws on either side of the physis has increased asymmetrically, confirming asymmetric growth rather than cessation of growth laterally. C: The angular deformity was treated with medial distal femoral epiphyseal stapling.
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Physeal Growth Disturbance

An uncommon but important complication of physeal fracture is physeal growth disturbance.106,113,134 The potential consequences of physeal growth disturbance include the development of angular deformity, limb length inequality, epiphyseal distortion, or various combinations of these. Development of these abnormalities, if any, depends on the physis affected, location within the affected physis, the duration of time present, and the skeletal maturity of the patient. Frequently, further surgery, often repeated and extensive, is required to correct or prevent deformity caused by an established growth disturbance.27,31,69,84,89,93,139,162 

Etiology

Disturbance of normal physeal growth may result from physical loss of the physis (such as after Peterson type VI injuries), from disruption of normal physeal architecture and function without actual radiograph loss of the physis, or by the formation of a physeal arrest, also called bony bridges or physeal bars.159 Careful identification of the nature of physeal growth disruption is important, because treatment strategies may differ based on the etiology of growth disturbance and the presence or absence of a true growth arrest. 
Growth disturbance as a result of physeal injury may result from direct trauma (physeal fracture)106,113,134 or associated vascular disruption.125 Infection,19,23 destruction by a space-occupying lesion such as unicameral bone cyst or enchondroma,150 infantile Blount disease,18 other vascular disturbances (such as purpura fulminans),14,65,78,88 irradiation,17,136 and other rare causes21,32,38 also may result in physeal growth disturbance or physeal arrest. 

Evaluation

Physeal growth disturbance may present as a radiographic abnormality noted on serial radiographs in a patient known to beat risk after fracture or infection, clinically with established limb deformity (angular deformity, shortening, or both), or occasionally incidentally on radiographs obtained for other reasons. The hallmark of plain radiographic features of physeal growth disturbance is the loss of normal physeal contour and the sharply defined radiolucency between epiphyseal and metaphyseal bones. Frank physeal arrests typically are characterized by sclerosis in the region of the arrest. If asymmetric growth has occurred, there may be tapering of a growth arrest line to the area of arrest,68,118 angular deformity, epiphyseal distortion, or shortening (Fig. 7-32). Physeal growth disturbance without frank arrest typically appears on plain radiographs as a thinner or thicker physeal area with an indistinct metaphyseal border because of alteration in normal enchondral ossification. There may be an asymmetric growth arrest line indicating angular deformity, but the arrest line will not taper to the physis itself (Fig. 7-33).118 This indicates altered physeal growth (either asymmetric acceleration or deceleration) but not a complete cessation of growth. This distinction is important, because the consequences and treatment are different from those caused by complete growth arrest. 
Figure 7-32
Harris growth arrest line tapering to the physis at the level of the growth arrest can serve as an excellent radiograph confirmation of the presence of the true growth arrest.
 
Although most commonly noted on plain radiographs, these arrest lines can be seen on CT scans and MRIs as well. A: Anteroposterior radiograph of the distal tibia after Salter–Harris type IV fracture demonstrates a Harris growth arrest line (arrows) tapering to the medial distal tibial physis, where a partial physeal arrest has formed. B: Harris growth arrest line (arrows) as noted on CT. CT scans with coronal (C) and sagittal (D) reconstructions corrected for bone distortion provide excellent images of the location and size of arrest.
Although most commonly noted on plain radiographs, these arrest lines can be seen on CT scans and MRIs as well. A: Anteroposterior radiograph of the distal tibia after Salter–Harris type IV fracture demonstrates a Harris growth arrest line (arrows) tapering to the medial distal tibial physis, where a partial physeal arrest has formed. B: Harris growth arrest line (arrows) as noted on CT. CT scans with coronal (C) and sagittal (D) reconstructions corrected for bone distortion provide excellent images of the location and size of arrest.
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Figure 7-32
Harris growth arrest line tapering to the physis at the level of the growth arrest can serve as an excellent radiograph confirmation of the presence of the true growth arrest.
Although most commonly noted on plain radiographs, these arrest lines can be seen on CT scans and MRIs as well. A: Anteroposterior radiograph of the distal tibia after Salter–Harris type IV fracture demonstrates a Harris growth arrest line (arrows) tapering to the medial distal tibial physis, where a partial physeal arrest has formed. B: Harris growth arrest line (arrows) as noted on CT. CT scans with coronal (C) and sagittal (D) reconstructions corrected for bone distortion provide excellent images of the location and size of arrest.
Although most commonly noted on plain radiographs, these arrest lines can be seen on CT scans and MRIs as well. A: Anteroposterior radiograph of the distal tibia after Salter–Harris type IV fracture demonstrates a Harris growth arrest line (arrows) tapering to the medial distal tibial physis, where a partial physeal arrest has formed. B: Harris growth arrest line (arrows) as noted on CT. CT scans with coronal (C) and sagittal (D) reconstructions corrected for bone distortion provide excellent images of the location and size of arrest.
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Figure 7-33
In this case, the asymmetric growth arrest line is noted in the proximal tibial metaphysis on CT scan.
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Figure 7-33
Asymmetric growth arrest line that does not taper to the physis is a strong indication of the presence of physeal growth disturbance without frank physeal arrest.
In this case, the asymmetric growth arrest line is noted in the proximal tibial metaphysis on CT scan.
In this case, the asymmetric growth arrest line is noted in the proximal tibial metaphysis on CT scan.
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If a growth arrest is suspected on plain radiographs in a skeletally immature child, further evaluation is often warranted. CT scanning with sagittal and coronal reconstructions (orthogonal to the area of interest) may demonstrate clearly an area of bone bridging the physis between the epiphysis and the metaphysis (Fig. 7-32C,D). MRI is also a sensitive method of assessing normal physeal architecture (Fig. 7-34).36,51,60 Revealing images of the physis and the region of physeal growth disturbance can be obtained using three-dimensional spoiled recalled gradient echo images with fat saturation or fast spin echo proton density images with fat saturation (Fig. 7-35). MRI has the additional advantage of the opportunity to assess the organization of the residual physis that may indicate its relative “health.” This assessment may be helpful in cases of infection, irradiation, or tumor to determine if arrest resection is feasible based on the integrity of the remaining physis. With either CT or MRI, physeal arrests are characterized by an identifiable bridge of bone between the epiphysis and the metaphysis, whereas growth disruption without arrest demonstrates some degree of loss of normal physeal contour and architecture without the bony bridge or physeal bar. 
Figure 7-34
MRI scan of a patient with traumatic lateral distal femoral partial growth arrest.
 
Note Harris arrest line tapering to the site of the arrest.
Note Harris arrest line tapering to the site of the arrest.
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Figure 7-34
MRI scan of a patient with traumatic lateral distal femoral partial growth arrest.
Note Harris arrest line tapering to the site of the arrest.
Note Harris arrest line tapering to the site of the arrest.
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Figure 7-35
MRI scan (three-dimensional spoiled recalled gradient echo images with fat saturation) provides excellent visualization of the affected area and some sense of the integrity of the residual physis.
This patient has infantile Blount disease.
This patient has infantile Blount disease.
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Although definitive assessment of physeal growth disturbance or arrest may require advanced imaging, further evaluation by plain radiographs is also beneficial. Radiographs of the entire affected limb should be obtained to document the magnitude of angular deformity. Existing limb length inequality should be assessed by scanogram. An estimation of predicted growth remaining in the contralateral unaffected physis should be made based on a determination of the child's skeletal age and reference to an appropriate growth table.1113,64,71,72,102 

Physeal Arrests

Whenever a bridge of bone develops across a portion of physis, tethering of the metaphyseal and epiphyseal bone together may result (Table 7-4). Partial physeal arrests can result in angular deformity, joint distortion, limb length inequality, or combinations of these, depending on the location of the arrest, the rate and extent of growth remaining in the physis involved, and the health of the residual affected physis. Although these partial arrests are not common, their presence usually requires preventive or corrective surgical treatment to minimize the long-term sequelae of the disturbance of normal growth they can create (Fig. 7-36). 
 
Table 7-4
Potential Causes of Physeal Arrest Formation
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Table 7-4
Potential Causes of Physeal Arrest Formation
Physeal fracture
Traumatic vascular disruption
Transphyseal infection
Vascular collapse associated with infection (purpura fulminans)
Infantile Blount disease
Irradiation
Unicameral bone cyst
Enchondroma
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Figure 7-36
Physeal arrests create variable amounts of limb shortening, angular deformity, and epiphyseal distortion, depending on the duration of the arrest, the physis affected, and the size of the arrest.
 
A long, standing film of the lower extremities with the hip, knee, and ankle joints included provides an overall assessment of angular deformity and shortening.
A long, standing film of the lower extremities with the hip, knee, and ankle joints included provides an overall assessment of angular deformity and shortening.
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Figure 7-36
Physeal arrests create variable amounts of limb shortening, angular deformity, and epiphyseal distortion, depending on the duration of the arrest, the physis affected, and the size of the arrest.
A long, standing film of the lower extremities with the hip, knee, and ankle joints included provides an overall assessment of angular deformity and shortening.
A long, standing film of the lower extremities with the hip, knee, and ankle joints included provides an overall assessment of angular deformity and shortening.
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Classification

Partial physeal arrests can be classified by etiology and by anatomic pattern. Potential etiologies of physeal arrest are summarized in Table 7-4 and include physeal fracture, Blount disease, infection, tumor, frostbite, and irradiation. Physeal arrests also can be classified based on the anatomic relationship of the arrest to the residual “healthy” physis. Three basic patterns are recognized (Fig. 7-37): Central, peripheral, and linear. A central arrest is surrounded by a perimeter of normal physis, like an island within the remaining physis. Central arrests are most likely to cause tenting of the articular surface, but also may result in angular deformity, if eccentrically located, and limb length inequality (Fig. 7-38). A peripheral arrest is located at the perimeter of the affected physis. This type of arrest primarily causes progressive angular deformity and variable shortening. A linear arrest is a “through-and-through” lesion with anatomic characteristics of both a central and peripheral arrest; specifically, the affected area starts at the perimeter of the physis and extends centrally with normal physis on either side of the affected area. Linear arrests most commonly develop after Salter–Harris type III or IV physeal fractures of the medial malleolus. 
Figure 7-37
Anatomic classification of physeal arrests.
 
Central arrests are surrounded by a perimeter of normal physis. Peripheral arrests are located at the perimeter of the physis. Linear arrests are “through-and-through” lesions with normal physis on either side of the arrest area.
Central arrests are surrounded by a perimeter of normal physis. Peripheral arrests are located at the perimeter of the physis. Linear arrests are “through-and-through” lesions with normal physis on either side of the arrest area.
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Figure 7-37
Anatomic classification of physeal arrests.
Central arrests are surrounded by a perimeter of normal physis. Peripheral arrests are located at the perimeter of the physis. Linear arrests are “through-and-through” lesions with normal physis on either side of the arrest area.
Central arrests are surrounded by a perimeter of normal physis. Peripheral arrests are located at the perimeter of the physis. Linear arrests are “through-and-through” lesions with normal physis on either side of the arrest area.
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Figure 7-38
Central arrests are characterized by tenting of the articular surface.
 
Variable shortening and angular deformity will develop, depending on the size and location of the arrest.
Variable shortening and angular deformity will develop, depending on the size and location of the arrest.
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Figure 7-38
Central arrests are characterized by tenting of the articular surface.
Variable shortening and angular deformity will develop, depending on the size and location of the arrest.
Variable shortening and angular deformity will develop, depending on the size and location of the arrest.
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Management

Several management alternatives are available. It is important to be aware of these and to weigh carefully the appropriateness of each for the individual situation. 
Prevention of Arrest Formation
Ideally, the surgeon should be proactive in the prevention of physeal arrest formation. Most commonly, this can be accomplished by adhering to the general treatment principles of physeal fractures: Gentle, anatomic, and secure reduction of the fracture, especially Salter–Harris types III and IV injuries. Damaged, exposed physes can be protected by immediate fat grafting,57 similar to the principle of interposition material insertion for the resection of established arrests (see following discussion). Although there is little evidence to support the practice, the most common situation in which this technique is utilized during open reduction of medial malleolar fractures, where comminution or partial physeal damage is identified during reduction. 
Some experimental work152 indicates that nonsteroidal anti-inflammatory medications (specifically indomethacin) given for a period of time after physeal injury may prevent formation of physeal arrest. There is, however, no clinical study supporting this experimental study, so the use of nonsteroidal anti-inflammatory medications is empiric and not common clinical practice. 
Partial Physeal Arrest Resection
Conceptually, surgical resection of a physeal arrest (sometimes referred to as physiolysis or epiphysiolysis) restoring normal growth of the affected physis is the ideal treatment for this condition.27,31,41,59,84,89,92,93,106,121,161 The principle is to remove the bony tether between the metaphysis and the physis and fill the physeal defect with a bone reformation retardant, anticipating that the residual healthy physis will resume normal longitudinal growth.27,59,89,92,93,121 However, this procedure can be technically demanding, and results in our practice are modest (see comment below). To determine if this procedure is indicated, careful consideration must be given to the location and extent of the arrest and the amount of longitudinal growth to be potentially salvaged (see discussion below). 
Physeal Distraction
Physeal arrests have been treated with the application of an external fixator spanning the arrest and gradual distraction until the arrest “separates.”35,45 Angular deformity correction and lengthening can be accomplished after separation as well. However, distraction injury usually results in complete cessation of subsequent normal physeal growth at the distracted level.55 Furthermore, the fixation wires or half pins may have tenuous fixation in the epiphysis or violate the articular space, risking septic arthritis. Thus, this modality is rarely used. 
Repeated Osteotomies during Growth
The simplest method to correct angular deformity associated with physeal arrests is corrective osteotomy in the adjacent metaphysis. Of course, neither significant limb length inequality nor epiphyseal distortion that may result from the arrest is corrected by this strategy. However, in young patients with a great deal of growth remaining in whom previous physeal arrest resection has been unsuccessful or is technically not possible, this treatment may be a reasonable interim alternative until more definitive completion of arrest and management of limb length inequality is feasible. 
Completion of Epiphysiodesis and Management of Resulting Limb Length Discrepancy
An alternative strategy for the management of physeal arrests is to complete the epiphysiodesis to prevent recurrent angular deformity or epiphyseal distortion and manage the existing or potential limb length discrepancy appropriately. Management of the latter may be by simultaneous or subsequent lengthening of the affected limb segment or contralateral epiphysiodesis if the existing discrepancy is tolerable and lengthening is not desired. We believe that this course of management is specifically indicated if arrest resection has failed to result in restoration of longitudinal growth and in patients in whom the amount of growth remaining does not warrant an attempt at arrest resection. In our opinion, this treatment should be considered carefully in all patients with a physeal arrest. 

Physeal Arrest Resection

Based on our experience with the results of physeal arrest resection, the factors discussed in the following sections should be considered before determining if physeal arrest resection is indicated. 

Etiology of the Arrest

Arrests caused by trauma or infantile Blount disease have a better prognosis for resumption of normal growth, compared to those secondary to infection, tumor or tumor-like conditions, or irradiation are less likely to demonstrate growth after resection. 

Anatomic Type of the Arrest

Central and linear arrests have been reported to be more likely to demonstrate resumption of growth after resection,31 but our experience has not supported this observation. 

Physis Affected

Because proximal humeral and proximal femoral lesions are difficult to expose, a technically adequate resection is less likely in these areas. In our institutional experience, (currently unpublished) distal femoral bars have a poorer prognosis for growth after resection, whereas those of the distal tibia have a more favorable prognosis for the resumption of growth. 

Extent of the Arrest

The potential for resumption of longitudinal growth after arrest resection is influenced by the amount of physeal surface area affected.27,31,84 Arrests affecting more than 25% of the total surface area are unlikely to grow, and, except in patients in whom significant growth potential remains, alternative treatment strategies should be used. 

Amount of Growth Remaining in the Physis Affected

Some authors31,84,89,92,93,124 have stated that 2 years of growth remaining based on skeletal age determination is a prerequisite for arrest resection to be considered. Based on our results with this procedure, we find that 2 years of growth remaining is an inadequate indication for physeal arrest resection. We believe that the decision to perform arrest resection should be made on a combination of the calculated amount of growth remaining in the affected physis and the likelihood of resumption of growth. Scanogram (Fig. 7-39) will document the existing discrepancy, determination of skeletal age and consultation with the growth remaining tables for the affected physis1113,61,74,102 will allow calculation of the predicted discrepancy. 
Figure 7-39
Scanogram indicates the existing limb length inequality.
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Preoperative Planning and Surgical Principles

If physeal arrest resection is considered appropriate, some planning is required to maximize the opportunity for resumption of longitudinal growth. 
First, the extent and location of the arrest relative to the rest of the physis must be carefully documented. The most cost-effective method to accurately evaluate an arrest is with reconstructed sagittal and coronal CT images to provide views orthogonal to the affected physis. MRI may also be used and, with recent advancements in the capability to identify and quantify physeal arrests, may soon become the imaging study of choice. We currently prefer three-dimensional spoiled recalled gradient echo images with fat saturation or fast spin echo proton density images with fat saturation to visualize the physis. CT images allow precise delineation of bony margins and, at the current time, is cheaper than MRI. An estimation of the affected surface area can be computed with the assistance of the radiologist using a modification of the method of Carlson and Wenger (Fig. 7-40).37 The procedure should be planned with consideration of the principles discussed in the following section. 
Figure 7-40
Reconstructed MRIs allow estimation of the percentage of surface area of the physis affected by a growth arrest.
 
This workstation reconstruction delineates the perimeter of normal physis (border 2) and that of the physeal arrest (border 1). Surface area affected can be calculated from these reconstructions.
This workstation reconstruction delineates the perimeter of normal physis (border 2) and that of the physeal arrest (border 1). Surface area affected can be calculated from these reconstructions.
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Figure 7-40
Reconstructed MRIs allow estimation of the percentage of surface area of the physis affected by a growth arrest.
This workstation reconstruction delineates the perimeter of normal physis (border 2) and that of the physeal arrest (border 1). Surface area affected can be calculated from these reconstructions.
This workstation reconstruction delineates the perimeter of normal physis (border 2) and that of the physeal arrest (border 1). Surface area affected can be calculated from these reconstructions.
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Minimize Trauma

The arrest must be resected in a manner that minimizes trauma to the residual physis. Central lesions should be approached either through a metaphyseal window (Fig. 7-41) or through the intramedullary canal after a metaphyseal osteotomy. Peripheral lesions are approached directly, resecting the overlying periosteum to help prevent reformation of the arrest. Intraoperative imaging (fluoroscopy) is needed to keep the surgeon oriented properly to the arrest and the residual healthy physis. Care to provide adequate visualization of the surgical cavity is essential, because visualization is usually difficult even under “ideal” circumstances. A brilliant light source, magnification, and a dry surgical field are very helpful. An arthroscope can be inserted into a metaphyseal cavity to permit a circumferential view of the resection area.103 A high-speed burr worked in a gentle to-and-fro movement perpendicular to the physis is usually the most effective way to gradually remove the bone composing the arrest and expose the residual healthy physis (Fig. 7-42). By the end of the resection, all of the bridging bone between the metaphysis and the epiphysis should be removed, leaving a void in the physis where the arrest had been, and the perimeter of the healthy residual physis should be visible circumferentially at the margins of the surgically created cavity (Fig. 7-43). Recently, intraoperative CT has been reported to be an effective adjuvant to guide bar resection.83 
Figure 7-41
 
A: Central arrests are approached through a metaphyseal “window” or the medullary canal after metaphyseal osteotomy. B: The arrest is removed, leaving in its place a metaphyseal–epiphyseal cavity with intact physis surrounding the area of resection.
A: Central arrests are approached through a metaphyseal “window” or the medullary canal after metaphyseal osteotomy. B: The arrest is removed, leaving in its place a metaphyseal–epiphyseal cavity with intact physis surrounding the area of resection.
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Figure 7-41
A: Central arrests are approached through a metaphyseal “window” or the medullary canal after metaphyseal osteotomy. B: The arrest is removed, leaving in its place a metaphyseal–epiphyseal cavity with intact physis surrounding the area of resection.
A: Central arrests are approached through a metaphyseal “window” or the medullary canal after metaphyseal osteotomy. B: The arrest is removed, leaving in its place a metaphyseal–epiphyseal cavity with intact physis surrounding the area of resection.
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Figure 7-42
After complete resection, the healthy physis should be evident circumferentially within the cavity produced by the arrest resection.
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Figure 7-43
 
A: After the bar is resected, metallic markers are inserted in the epiphysis and metaphysis. B: Following marker placement fat graft is placed in the resection bed.
A: After the bar is resected, metallic markers are inserted in the epiphysis and metaphysis. B: Following marker placement fat graft is placed in the resection bed.
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Figure 7-43
A: After the bar is resected, metallic markers are inserted in the epiphysis and metaphysis. B: Following marker placement fat graft is placed in the resection bed.
A: After the bar is resected, metallic markers are inserted in the epiphysis and metaphysis. B: Following marker placement fat graft is placed in the resection bed.
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Prevent Reforming of Bridge Between Metaphysis and Epiphysis

A bone-growth retardant or “spacer” material should be placed in the cavity created by the arrest resection to prevent reforming of the bony bridge between the metaphysis and the epiphysis. Four compounds have been used for this purpose either clinically or experimentally: Autogenous fat,31,84,89,9295,162 methyl methacrylate,22,84,124 silicone rubber,27 and autogenous cartilage.16,18,56,66,85,97 Silicone rubber is no longer available and, to our knowledge, autogenous cartilage has been used only experimentally as a press-fit plug or cultured chondroblasts. Currently, only autogenous fat graft, harvested either locally or from the buttock, and methyl methacrylate are used clinically. Autogenous fat has at least a theoretic advantage of the ability to hypertrophy and migrate with longitudinal and interstitial growth (Fig. 7-44).94,95 Methyl methacrylate is inert, but provides some immediate structural stability.33 This feature may be important with large arrest resections in weight-bearing areas, as in the proximal tibia in association with infantile Blount disease (Fig. 7-45). However, embedded methyl methacrylate, especially products without barium to clearly delineate its location on radiograph, can be extremely difficult to remove and can jeopardize bone fixation if subsequent surgery is required. Pathologic fracture associated with methyl methacrylate migration from the metaphysis to diaphysis has also been reported.142 A number of recent studies have looked at the possibility of “grafting” the resected area of physis with chondrocytes or stem cells. Although promising, these techniques have not yet become clinically available and remain predominantly a research endeavor in laboratory animals.43,75,96,131,153,167 
Figure 7-44
Fat used as an interposition material in partial physeal arrest resection can persist and hypertrophy during longitudinal growth.
 
A: Radiograph appearance after traumatic distal radial physeal arrest resection. B: Appearance 5 years later. Longitudinal growth between the metallic markers is obvious. The fat-filled cavity created at physeal arrest resection has persisted and elongated with distal radial growth.
A: Radiograph appearance after traumatic distal radial physeal arrest resection. B: Appearance 5 years later. Longitudinal growth between the metallic markers is obvious. The fat-filled cavity created at physeal arrest resection has persisted and elongated with distal radial growth.
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Figure 7-44
Fat used as an interposition material in partial physeal arrest resection can persist and hypertrophy during longitudinal growth.
A: Radiograph appearance after traumatic distal radial physeal arrest resection. B: Appearance 5 years later. Longitudinal growth between the metallic markers is obvious. The fat-filled cavity created at physeal arrest resection has persisted and elongated with distal radial growth.
A: Radiograph appearance after traumatic distal radial physeal arrest resection. B: Appearance 5 years later. Longitudinal growth between the metallic markers is obvious. The fat-filled cavity created at physeal arrest resection has persisted and elongated with distal radial growth.
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Figure 7-45
Resection of substantial physeal arrests in weight-bearing areas may allow subsidence of the articular surface.
 
This is of particular concern in the proximal tibia of patients with infantile Blount disease. A: Early postoperative radiograph after partial physeal arrest resection in an obese patient with infantile Blount disease. B: One year later, the metallic markers are actually closer together, in addition to demonstrating increased varus. Subsidence of the medial proximal tibial articular surface is the likely explanation of this radiograph finding. Protected weight bearing or methyl methacrylate as the interposition material may be indicated in such cases.
This is of particular concern in the proximal tibia of patients with infantile Blount disease. A: Early postoperative radiograph after partial physeal arrest resection in an obese patient with infantile Blount disease. B: One year later, the metallic markers are actually closer together, in addition to demonstrating increased varus. Subsidence of the medial proximal tibial articular surface is the likely explanation of this radiograph finding. Protected weight bearing or methyl methacrylate as the interposition material may be indicated in such cases.
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Figure 7-45
Resection of substantial physeal arrests in weight-bearing areas may allow subsidence of the articular surface.
This is of particular concern in the proximal tibia of patients with infantile Blount disease. A: Early postoperative radiograph after partial physeal arrest resection in an obese patient with infantile Blount disease. B: One year later, the metallic markers are actually closer together, in addition to demonstrating increased varus. Subsidence of the medial proximal tibial articular surface is the likely explanation of this radiograph finding. Protected weight bearing or methyl methacrylate as the interposition material may be indicated in such cases.
This is of particular concern in the proximal tibia of patients with infantile Blount disease. A: Early postoperative radiograph after partial physeal arrest resection in an obese patient with infantile Blount disease. B: One year later, the metallic markers are actually closer together, in addition to demonstrating increased varus. Subsidence of the medial proximal tibial articular surface is the likely explanation of this radiograph finding. Protected weight bearing or methyl methacrylate as the interposition material may be indicated in such cases.
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Marker Implantation

Metallic markers should be implanted in the epiphysis and metaphysis at the time of arrest resection to allow reasonably accurate estimation of the amount of longitudinal growth that occurs across the operated physis, as well as to identify the deceleration or cessation of that growth (Fig. 7-46). We believe that precise monitoring of subsequent longitudinal growth is an important aspect of the management of patients after arrest resection. First, resumption of longitudinal growth may not occur despite technically adequate arrest resection in patients with good clinical indications. Perhaps more importantly, resumption of normal or even accelerated longitudinal growth may be followed by late deceleration or cessation of that growth.69 It is imperative that the treating surgeon be alert to those developments, so that proper intervention can be instituted promptly. Embedded metallic markers serve those purposes admirably. 
Figure 7-46
Intraosseous metallic markers in the epiphysis and metaphysis spanning the area of arrest resection allow sensitive radiographic documentation of the presence and extent of growth after arrest resection and permit early detection of the cessation of restored longitudinal growth.
 
This patient had a small central arrest of the lateral portion of the distal femoral physis after a Salter–Harris type IV fracture. A: Injury films show a mildly displaced Salter–Harris type IV fracture of the lateral distal femur. B: Several years later, a small central arrest has developed involving a portion of the lateral distal femoral physis. A tapering growth arrest line is faintly visible. C: The posterior location of the partial arrest can be seen on the sagittal CT reconstructions. D: After arrest resection through a metaphyseal window, a cavity is evident in the region of the original bar. Metallic markers have been placed in the metaphysis and epiphysis. E: Three years after arrest resection, substantial growth has occurred, as documented by the increased distance between the markers. However, on radiographs taken at 4 years postoperatively, no further growth was documented. This event was treated by completion of the epiphysiodesis and contralateral distal femoral epiphysiodesis to prevent the development of limb length discrepancy from developing.
This patient had a small central arrest of the lateral portion of the distal femoral physis after a Salter–Harris type IV fracture. A: Injury films show a mildly displaced Salter–Harris type IV fracture of the lateral distal femur. B: Several years later, a small central arrest has developed involving a portion of the lateral distal femoral physis. A tapering growth arrest line is faintly visible. C: The posterior location of the partial arrest can be seen on the sagittal CT reconstructions. D: After arrest resection through a metaphyseal window, a cavity is evident in the region of the original bar. Metallic markers have been placed in the metaphysis and epiphysis. E: Three years after arrest resection, substantial growth has occurred, as documented by the increased distance between the markers. However, on radiographs taken at 4 years postoperatively, no further growth was documented. This event was treated by completion of the epiphysiodesis and contralateral distal femoral epiphysiodesis to prevent the development of limb length discrepancy from developing.
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This patient had a small central arrest of the lateral portion of the distal femoral physis after a Salter–Harris type IV fracture. A: Injury films show a mildly displaced Salter–Harris type IV fracture of the lateral distal femur. B: Several years later, a small central arrest has developed involving a portion of the lateral distal femoral physis. A tapering growth arrest line is faintly visible. C: The posterior location of the partial arrest can be seen on the sagittal CT reconstructions. D: After arrest resection through a metaphyseal window, a cavity is evident in the region of the original bar. Metallic markers have been placed in the metaphysis and epiphysis. E: Three years after arrest resection, substantial growth has occurred, as documented by the increased distance between the markers. However, on radiographs taken at 4 years postoperatively, no further growth was documented. This event was treated by completion of the epiphysiodesis and contralateral distal femoral epiphysiodesis to prevent the development of limb length discrepancy from developing.
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Figure 7-46
Intraosseous metallic markers in the epiphysis and metaphysis spanning the area of arrest resection allow sensitive radiographic documentation of the presence and extent of growth after arrest resection and permit early detection of the cessation of restored longitudinal growth.
This patient had a small central arrest of the lateral portion of the distal femoral physis after a Salter–Harris type IV fracture. A: Injury films show a mildly displaced Salter–Harris type IV fracture of the lateral distal femur. B: Several years later, a small central arrest has developed involving a portion of the lateral distal femoral physis. A tapering growth arrest line is faintly visible. C: The posterior location of the partial arrest can be seen on the sagittal CT reconstructions. D: After arrest resection through a metaphyseal window, a cavity is evident in the region of the original bar. Metallic markers have been placed in the metaphysis and epiphysis. E: Three years after arrest resection, substantial growth has occurred, as documented by the increased distance between the markers. However, on radiographs taken at 4 years postoperatively, no further growth was documented. This event was treated by completion of the epiphysiodesis and contralateral distal femoral epiphysiodesis to prevent the development of limb length discrepancy from developing.
This patient had a small central arrest of the lateral portion of the distal femoral physis after a Salter–Harris type IV fracture. A: Injury films show a mildly displaced Salter–Harris type IV fracture of the lateral distal femur. B: Several years later, a small central arrest has developed involving a portion of the lateral distal femoral physis. A tapering growth arrest line is faintly visible. C: The posterior location of the partial arrest can be seen on the sagittal CT reconstructions. D: After arrest resection through a metaphyseal window, a cavity is evident in the region of the original bar. Metallic markers have been placed in the metaphysis and epiphysis. E: Three years after arrest resection, substantial growth has occurred, as documented by the increased distance between the markers. However, on radiographs taken at 4 years postoperatively, no further growth was documented. This event was treated by completion of the epiphysiodesis and contralateral distal femoral epiphysiodesis to prevent the development of limb length discrepancy from developing.
View Original | Slide (.ppt)
This patient had a small central arrest of the lateral portion of the distal femoral physis after a Salter–Harris type IV fracture. A: Injury films show a mildly displaced Salter–Harris type IV fracture of the lateral distal femur. B: Several years later, a small central arrest has developed involving a portion of the lateral distal femoral physis. A tapering growth arrest line is faintly visible. C: The posterior location of the partial arrest can be seen on the sagittal CT reconstructions. D: After arrest resection through a metaphyseal window, a cavity is evident in the region of the original bar. Metallic markers have been placed in the metaphysis and epiphysis. E: Three years after arrest resection, substantial growth has occurred, as documented by the increased distance between the markers. However, on radiographs taken at 4 years postoperatively, no further growth was documented. This event was treated by completion of the epiphysiodesis and contralateral distal femoral epiphysiodesis to prevent the development of limb length discrepancy from developing.
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Author's Observation

It has been our clinical observation that even patients who have significant resumption of growth following arrest resection will experience premature cessation of longitudinal growth of the affected physis relative to the contralateral uninvolved physis. We believe that even if growth resumes after bar resection, the previously injured physis will cease growing before the contralateral physis. Thus, the percent of predicted growth might be expected to decrease over the length of follow-up. 
Our experience with physeal arrest resection prompted several conclusions and treatment recommendations. 
  •  
    On average, approximately 60% of physeal arrests demonstrate clear radiograph evidence of resumption of longitudinal growth of the affected physis after physeal arrest resection.
  •  
    There is a correlation between the amount of surface area of the physis affected and the prognosis for subsequent longitudinal growth after arrest resection. Physeal arrests affecting less than 10% of the surface area of the physis have a better prognosis than larger arrests.
  •  
    Langenskiöld stage VI infantile Blount disease has results comparable to posttraumatic physeal arrests.
  •  
    Etiologies other than posttraumatic and infantile Blount disease have poor prognoses for subsequent growth.
  •  
    Central and peripheral arrests have equivalent prognoses with respect to resumption of growth.
  •  
    Early growth resumption may be followed by cessation of longitudinal growth before skeletal maturity. As a consequence, patients must be evaluated regularly until skeletal maturity with some reliable method (such as metaphyseal and epiphyseal radiograph markers) to detect such development as promptly as possible.
We believe that physeal bar resection has a role to play in patients with significant longitudinal growth remaining. However, the benefits of such surgery must be weighed against the actual amount of growth remaining, and the etiology, location, and extent of the physeal arrest must be considered. The appropriate time to add a corrective osteotomy to bony bar resection is controversial. Generally, when the angular deformity is more than 10 to 15 degrees from normal, corrective osteotomy should be considered. 

Growth Disturbance without Arrest

Recognition

Growth disturbance may also occur without physeal arrest. Both growth deceleration and, less frequently, acceleration have been reported. Growth deceleration without arrest is characterized radiographically by the appearance of an injured physis (usually relative widening of the physis with indistinct metaphyseal boundaries). There may be associated clinical or radiographic deformity if the disturbance is severe and long standing. It is important to make a distinction between growth deceleration without complete cessation and true physeal arrest, because management and outcome are typically different in these two disorders. The concept of growth deceleration without arrest is most readily appreciated in patients with adolescent Blount disease and the milder stages of infantile Blount disease. Recently, growth deceleration without physeal arrest has also been reported to produce distal femoral valgus deformity in obese adolescents.146 Growth deceleration may also occur after infection and physeal fracture. In contrast to physeal arrests, there is no sclerotic area of arrest on plain radiographs (Fig. 7-33). A growth arrest line, if present, may be asymmetric but will not taper to the physis, thereby suggesting growth asymmetry but not complete arrest. Furthermore, in some cases, deformity will not be relentlessly progressive and can actually improve over time. 
Growth acceleration most classically occurs following proximal tibial fracture in young patients resulting in valgus deformity which usually spontaneously resolves.77,82,120,145,146,169 Interestingly, it has also recently been reported to occur in patients younger than 10 years who have had curettage of benign lesions of the proximal tibial metaphysis.70 

Management

The diagnosis of physeal growth disturbance is usually made incidentally by noting physeal abnormality on radiographs during physeal fracture follow-up or after a diagnosis of frank physeal arrest has been excluded during the evaluation of a patient with angular deformity and physeal abnormality on plain radiographs. Once a growth disturbance has been identified in a patient, its full impact should be assessed by determining the presence and extent of limb length inequality and the calculated amount of potential growth remaining for the affected physis. 
In some cases, the radiographic abnormality is stable and only longitudinal observation is required. This observation must be regular and careful, because progressive deformity will require treatment. If angular deformity is present or progressive, treatment options include hemiepiphysiodesis or physeal “tethering” with staples, screws, or tension plates24,42,54,58,108,109,116,144,151,160 and corrective osteotomy, with or without completion of the epiphysiodesis. In the absence of frank arrest formation, hemiepiphysiodesis or “tethering” the affected physis with staples, screws, or tension plates on the convex side may result in gradual correction of the deformity. If correction occurs, options include completion of the epiphysiodesis (with contralateral epiphysiodesis if necessary to prevent the development of significant leg length deformity) and removal of the tethering device with careful longitudinal observation for recurrence or overcorrection of deformity. Although there have been numerous publications regarding the various techniques and implants for physeal tethering, there is to date no solid evidence to support one technique. One pitfall to avoid is that a “tethering” technique (staples, plate, screw) opposite a known partial physeal arrest is unlikely to lead to correction of angular deformity, and is likely to lead to a complete growth arrest. 
Corrective osteotomy is the other option for the management of growth disturbance with established angular deformity. Angular deformity correction in the early stages of infantile and adolescent Blount disease is known to result in resolution of the physeal growth disturbance in some patients, both on radiographs and clinically. We are unaware of confirmation of similar outcome when the etiology of growth disturbance is infection or trauma, although it may occur. Thus, the treating surgeon must decide whether to perform epiphysiodesis of the affected physis (with contralateral epiphysiodesis, if appropriate) to prevent recurrence or to ensure careful longitudinal observation of the growth performance of the affected physis until skeletal maturity. 

Summary

Physeal fractures are one of the unique aspects of pediatric orthopedics. These injuries are common and usually have a favorable outcome without long-term sequelae. Physeal fractures must be treated gently and expertly to maximize restoration of normal limb function and longitudinal growth. Depending on the severity and nature of physeal injury, longitudinal follow-up to identify the development of physeal growth disturbance is important. 

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