eMedicine Specialties > Orthopedic Surgery > Pediatrics

Growth Plate (Physeal) Fractures: Follow-up

Author: Charles T Mehlman, DO, MPH, Director, Musculoskeletal Outcomes Research, Associate Professor, Division of Pediatric Orthopedic Surgery, Cincinnati Children's Hospital Medical Center
Coauthor(s): Matthew E Koepplinger, DO, Assistant Professor, Department of Orthopaedic Surgery, Baylor College of Medicine; Staff Physician, Department of Orthopaedic Surgery, Ben Taub General Hospital, Houston
Contributor Information and Disclosures

Updated: Aug 12, 2008

Outcome and Prognosis

High-risk and significant-risk fractures

Distal femur fractures

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

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

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

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

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

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

Distal tibia fractures

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

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

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

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

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

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

Distal radius and ulna fractures

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

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

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

Proximal tibia fractures

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

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

Triradiate cartilage fractures

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

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

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

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

Stubbed great toe

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

Future and Controversies

Growth plate transplantation

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

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

Tissue engineering

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

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

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

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

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

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