Pediatric Tibia and Fibula

Uncommon, representing <5% of pediatric fractures and 11% of pediatric tibia fractures.

Peak incidence is at 3 to 6 years.

The proximal tibial physis is generally
structurally weaker than the metaphyseal region; this accounts for the
lower incidence of fractures in the tibial metaphysis.

Most common is force applied to lateral
aspect of the extended knee that causes the cortex of the medial
metaphysis to fail in tension, usually as nondisplaced greenstick
fractures of the medial cortex.

The fibula usually does not fracture, although plastic deformation may occur.

The patient typically presents with pain, swelling, and tenderness in the region of the fracture.

Motion of the knee is painful, and the child usually refuses to ambulate.

Valgus deformity is typically present.

AP and lateral views of the tibia should
be obtained, as well as appropriate views of the knee and ankle to rule
out associated injuries.

Progressive valgus angulation: May result
from a combination of factors, including disruption of the lateral
physis at the time of injury, exuberant medial callus formation that
results in fracture overgrowth, entrapment of periosteum at the medial
fracture site with consequent stimulation of the physis, or concomitant
pes anserinus injury that results in a loss of inhibitory tethering
effect on the physis, allowing overgrowth. The deformity is most
prominent within 1 year of fracture; younger patients may experience
spontaneous correction with remodeling, although older patients may
require hemiepiphysiodesis or corrective osteotomy.

Premature proximal tibial physeal
closure: May occur with unrecognized crush injury (Salter V) to the
proximal tibial physis, resulting in growth arrest. This most commonly
affects the anterior physis and leads to a recurvatum deformity of the
affected knee.

Of pediatric tibial fractures, 39% occur in the middle third.

Approximately 30% of pediatric diaphyseal
fractures are associated with a fracture of the fibula. Occasionally,
this is in the form of plastic deformation, producing valgus alignment
of the tibia.

Isolated fractures of the fibular shaft are rare and result from direct trauma to the lateral aspect of the leg.

The nutrient artery arises from the
posterior tibial artery, entering the posterolateral cortex distal to
the origination of the soleus muscle, at the oblique line of the tibia.
Once the vessel enters the intramedullary canal, it gives off three
ascending branches and one descending branch. These give rise to the
endosteal vascular tree, which anastomoses with periosteal vessels
arising from the anterior tibial artery.

The anterior tibial artery is particularly vulnerable to injury as it passes through a hiatus in the interosseus membrane.

The peroneal artery has an anterior communicating branch to the dorsalis pedis artery.

The fibula is responsible for 6% to 17%
of weight-bearing load. The common peroneal nerve courses around the
neck of the fibula, which is nearly subcutaneous in this region; it is
therefore especially vulnerable to direct blows or traction injuries at
this level.

Direct: Trauma to the leg occurs, mostly in the form of vehicular trauma or pedestrian-motor vehicle accident.

Indirect: In younger children, most
tibial fractures result from torsional forces. These spiral and oblique
fractures occur as the body mass rotates on a planted foot. The fibula
prevents significant shortening when intact, but the fracture
frequently falls into varus.

The patient typically presents with pain, swelling, and tenderness in the region of the fracture.

Motion of the knee is painful, and the child usually refuses to ambulate.

Children with stress fractures of the tibia may complain of pain on weight bearing that is partially relieved by rest.

Standard AP and lateral views of the leg should be obtained.

Radiographs of the ipsilateral ankle and knee should be obtained to rule out associated injuries.

Comparison views of the uninjured, contralateral leg may be obtained in cases in which the diagnosis is unclear.

Technetium bone scan or MRI may be obtained to rule out occult fracture.

Compartment syndrome: In pediatric tibia
fractures, compartment syndrome is most common after severe injury in
which the interosseous membrane surrounding the anterior compartment is
disrupted. Patients with elevated compartment pressures >30 mm Hg or
within 30 mm Hg of diastolic blood pressure should receive emergency
fasciotomies of all four compartments of the leg to avoid neurologic
and ischemic sequelae.

Angular deformity: Correction of deformity varies by age and gender.

Malrotation: Rotational deformity of the
tibia does not correct with remodeling and is poorly tolerated, often
resulting in malpositioning of the foot with the development of
associated ankle and foot problems. Supramalleolar osteotomy may be
required for rotational correction.

Premature proximal tibial physeal
closure: This may occur with unrecognized crush injury (Salter Type V)
to the proximal tibial physis, resulting in growth arrest. This most
commonly affects the anterior physis and leads to a recurvatum
deformity of the affected knee.

Delayed union and nonunion: Uncommon in
children, but it may occur as a result of infection, the use of
external fixation, or inadequate immobilization. Fibulectomy, bone
grafting, reamed intramedullary nailing (adolescents), and plate
fixation with bone grafting have all been described as methods to treat
tibial nonunions in the pediatric population.

Fractures of the distal third of the tibia comprise approximately 50% of pediatric tibia fractures.

Most occur in patients younger than 14 years, with the peak range of incidence in children between ages 2 and 8 years.

Distally, the tibia flares out as the
cortical diaphyseal bone changes to cancellous metaphyseal bone
overlying the articular surface. This is similar to the tibial plateau
in that there is primarily cancellous bone within a thin cortical shell.

Indirect: An axial load results from a jump or fall from a height.

Direct: Trauma to the lower leg occurs,
such as in bicycle spoke injuries in which a child’s foot is thrust
forcibly between the spokes of a turning bicycle wheel, resulting in
severe crush to the distal leg, ankle, and foot with variable soft
tissue injury.

Patients typically are unable to ambulate or are ambulatory only with severe pain.

Although swelling may be present with
variable abrasions or lacerations, the foot, ankle, and leg typically
appear relatively normal without gross deformity.

The entire foot, ankle, and leg should be
exposed to evaluate the extent of soft tissue injury and to assess for
possible open fracture.

A careful neurovascular examination is important, and the presence of compartment syndrome must be excluded.

In cases of bicycle spoke injuries,
palpation of all bony structures of the foot and ankle should be
performed as well as assessment of ligamentous integrity and stability.

AP and lateral views of the leg should be
obtained. Appropriate views of the ankle and knee should be taken to
rule out associated injuries, as well as views of the foot as indicated.

Fractures of the distal metaphysis
typically represent greenstick injuries, with anterior cortical
impaction, posterior cortical disruption, and tearing of the overlying
periosteum, often resulting in a recurvatum pattern of injury.

In severe torsional injuries with impaction or distraction forces, a spiral fracture may result.

Computed tomography is usually unnecessary, but it may aid in fracture definition in comminuted or complex fractures.

Recurvatum: Inadequate reduction or
fracture subsidence may result in a recurvatum deformity at the
fracture. Younger patients tend to tolerate this better, because
remodeling typically renders the deformity clinically insignificant.
Older patients may require supramalleolar osteotomy for severe
recurvatum deformity that compromises ankle function and gait.

Premature distal tibial physeal closure:
May occur with unrecognized crush injury (Salter Type V) to the distal
tibial physis, resulting in growth arrest.

A toddler’s fracture is by definition a spiral fracture of the tibia in the appropriate age group.

Most of these fractures occur in children younger than 2.5 years.

The average age of incidence is 27 months.

This tends to occur in boys more often than in girls and in the right leg more frequently than the left.

The distal epiphysis appears at
approximately 2 years of age; thus, physeal injuries of the distal
tibia may not be readily apparent and must be suspected.

The classic description of the mechanism
of a toddler’s fracture is external rotation of the foot with the knee
in fixed position, producing a spiral fracture of the tibia with or
without concomitant fibular fracture.

This injury has also been reported as a result of a fall.

Patients typically present irritable and nonambulatory or with an acute limp.

The examination of a child refusing to
ambulate without readily identifiable causes should include a careful
history, with attention to temporal progression of symptoms and signs
(e.g., fever), as well as a systematic evaluation of the hip, thigh,
knee, leg, ankle, and foot, with attention to points of tenderness,
swelling, or ecchymosis. This should be followed by radiographic
evaluation as well as appropriate laboratory analysis if the diagnosis
remains in doubt.

In the case of a toddler’s fracture, pain
and swelling are variable on palpation of the tibia. These features are
usually appreciated over the anteromedial aspect of the tibia, where
its subcutaneous nature allows for minimal soft tissue protection.

AP and lateral views of the leg should be obtained.

An internal oblique radiograph of the leg may be helpful for demonstration of a nondisplaced spiral fracture.

Occasionally, an incomplete fracture may
not be appreciated on presentation radiographs but may become
radiographically evident 7 to 10 days after the injury as periosteal
new bone formation occurs.

Technetium bone scans may aid in the
diagnosis of toddler’s fracture by visualization of diffusely increased
uptake throughout the tibia. This may be differentiated from infection,
which tends to produce a localized area of increased uptake.

A long leg cast for 2 to 3 weeks followed
by conversion to a short leg walking cast for an additional 2 to 3
weeks is usually sufficient.

Manipulation is generally not necessary because angulation and displacement are usually minimal and within acceptable limits.

Complications of toddler’s fractures are
rare owing to the low-energy nature of the injury, the age of the
patient, and the rapid and complete healing that typically accompanies
this fracture pattern.

Rotational deformity: Toddler’s fractures
may result in clinically insignificant rotational deformity of the
tibia as the fracture slides minimally along the spiral configuration.
This is usually unnoticed by the patient but may be appreciated on
comparison examination of the lower limbs.

Most tibia stress fractures occur in the proximal third.

The peak incidence of tibia stress fractures in children is between the ages of 10 and 15 years.

Most fibula stress fractures occur in the distal third.

The peak incidence of fibula stress fractures in children is between the ages of 2 and 8 years.

The tibia is more often affected than the fibula in children; the opposite is true in adults.

An acute fracture occurs when the force
applied to a bone exceeds the bone’s capacity to withstand it. A stress
fracture occurs when a bone is subjected to repeated trauma with a
strain that is less than what would have produced an acute fracture.

With microtrauma, osteoclastic tunnel
formation increases to remodel microcracks. New bone formation results
in the production of immature, woven bone that lacks the strength of
the mature bone it replaced, predisposing the area to fracture with
continued trauma.

Stress fractures in older children and adolescents tend to be as a result of athletic participation.

Distal fibula stress fractures have been
referred to as the “ice skater’s fracture,” because of the repeated
skating motion that results in a characteristic fibular fracture
approximately 4 cm proximal to the lateral malleolus.

Patients typically presents with an antalgic gait that is relieved by rest, although younger patients may refuse to ambulate.

The pain is usually described as insidious in onset, worse with activity, and improved at night.

Swelling is generally not present,
although the patient may complain of a vague ache over the site of
fracture with tenderness to palpation.

Knee and ankle range of motion are usually full and painless.

Occasionally, the patient’s symptoms and signs may be bilateral.

Muscle sprains, infection, and
osteosarcoma must be excluded. Exercise-induced compartment syndrome
overlying the tibia may have a similar clinical presentation.

AP and lateral views of the leg should be
obtained to rule out acute fracture or other injuries, although stress
fractures are typically not evident on standard radiographs for 10 to
14 days after initial onset of symptoms.

Radiographic evidence of fracture repair
may be visualized as periosteal new bone formation, endosteal
radiodensity, or the presence of “eggshell” callus at the site of
fracture.

Technetium bone scan reveals a localized
area of increased tracer uptake at the site of fracture and may be
performed within 1 to 2 days of injury.

Computed tomography rarely demonstrates
the fracture line, although it may delineate increased marrow density
and endosteal/periosteal new bone formation and soft tissue edema.

Magnetic resonance imaging may demonstrate a localized band of very low signal intensity continuous with the cortex.

Stress fractures may be classified as
complete versus incomplete or acute versus chronic or recurrent. They
rarely are displaced or angulated.

The treatment of a child presenting with a tibia or fibula stress fracture begins with activity modification.

The child may be placed in a long leg
(tibia) or short leg (fibula) cast, initially non–weight bearing with a
gradual increase in activity level. The cast should be maintained for 4
to 6 weeks until the fracture site is nontender and radiographic
evidence of healing occurs.

Nonunion may be addressed with open excision of the nonunion site with iliac crest bone grafting or electrical stimulation.

Recurrent stress fractures: These may be
the result of overzealous training regimens, such as for gymnastics or
ice skating. Activity modification must be emphasized to prevent
recurrence.

Nonunion: Rare, occurring most commonly in the middle third of the tibia.