Orthopaedic Surgery - Femoral Shaft Fracture in the Child

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Basics

A pediatric femoral shaft fracture involves the diaphyseal portion of the femur, generally defined as a fracture occurring more than approximately 5 cm distal to the lesser trochanter and proximal to the widened distal metaphysis.

The fracture is commonly described according to its location as proximal, midshaft, or distal.

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Mechanism

The normal femur is a strong bone and usually requires substantial force to fracture.

However, femoral shaft fractures can occur after relatively low-energy trauma in infants, toddlers, or children with structurally weakened bone.

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Prevention

Prevention includes appropriate supervision and age-appropriate safety measures.

Children with a known femoral lesion or substantial bone weakness may need to avoid high-impact or contact activities that significantly increase fracture risk.

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Epidemiology

Femoral fractures occur more commonly in areas of high population density and lower socioeconomic status.

There is a bimodal age pattern, with increased frequency in children approximately 0–3 years old and 12–16 years old.

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Pathophysiology

Different fracture configurations may suggest particular mechanisms of injury, although the fracture pattern alone does not prove how the injury occurred.

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Buckle Pattern

A buckle-type injury may suggest a direct impact.

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Spiral Fracture

A spiral fracture often reflects a rotational or twisting force.

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Transverse Fracture

A transverse pattern may result from a direct blow applied from the side.

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Comminuted or Open Fracture

A comminuted or open fracture generally suggests either very high-energy trauma or markedly weakened bone.

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Post-Fracture Overgrowth

Children commonly demonstrate approximately 1–1.5 cm of femoral overgrowth during the first 18 months after fracture healing.

This phenomenon allows a degree of initial shortening to be accepted during treatment, especially in younger children.

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Etiology by Age

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Age 0–2 Years

In infants younger than approximately 12 months, nonaccidental injury must always be considered.

Other causes include falls from a height.

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Age 2–5 Years

Common mechanisms include falls from height, falls during play, and pedestrian-versus-motor vehicle injuries.

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Age 5–16 Years

Older children and adolescents more often sustain femoral shaft fractures from bicycle accidents, pedestrian trauma, motor vehicle collisions, and sports injuries.

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Associated Conditions

Some fractures occur through abnormal bone.

Important underlying disorders include osteogenesis imperfecta, unicameral bone cyst, fibrous cortical defect or nonossifying fibroma, fibrous dysplasia, and neurologic disorders such as cerebral palsy.

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Associated Traumatic Injuries

Because many femoral shaft fractures result from significant trauma, additional injuries may occur.

These include head injury, spinal fracture, upper-extremity fracture, and other lower-extremity injuries.

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Diagnosis

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History

The history should document the mechanism, timing, and circumstances of injury.

If a pathologic fracture is suspected, the child should be asked about pain before the injury, previous fractures, or known bone disease.

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Suspected Nonaccidental Injury

When abuse is a possibility, the history should be obtained carefully from caregivers and witnesses.

Important details include the child’s position before the event, the proposed mechanism, whether that mechanism is developmentally plausible, and what occurred immediately afterward.

Any inconsistency between the history and injury pattern warrants further evaluation.

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Physical Examination

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Thigh Appearance

The thigh is usually swollen and painful.

When the fracture is displaced, the limb often appears shortened and externally rotated.

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Pain With Rotation

Internal or external rotation of the leg usually causes marked pain at the fracture site.

The limb should therefore be handled gently.

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Knee Examination

The knee may be swollen even when no ligamentous injury is present.

A more complete ligament examination can be performed after the femur has been stabilized and pain has improved.

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Neurovascular Examination

Distal pulses, capillary refill, motor function, and sensation should be documented.

Neurovascular injury is uncommon but must not be missed.

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Examination for Abuse

If nonaccidental injury is suspected, the child should be examined for additional bruises, tenderness, fractures, or other signs of trauma.

Further evaluation for occult injuries should follow child-protection protocols.

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Imaging

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Plain Radiographs

Plain radiographs are usually sufficient to establish the diagnosis.

AP and lateral views should include the entire femur and adjacent joints whenever possible.

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MRI or CT

MRI or CT may be needed when an occult nondisplaced fracture, stress fracture, or underlying lesion is suspected but plain radiographs are inconclusive.

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Skeletal Survey

When nonaccidental trauma is suspected, a skeletal survey may be indicated according to the child’s age and clinical situation.

Additional imaging may be required depending on findings.

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Diagnostic Procedures

If a malignant bone lesion is suspected, biopsy should be performed before definitive surgical treatment.

This situation is uncommon but important because inappropriate fixation through an undiagnosed tumor can complicate later oncologic management.

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Pathological Findings

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Osteogenesis Imperfecta

Thin cortices and generalized bowing may suggest osteogenesis imperfecta.

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Fibrous Dysplasia

A broad area of abnormal cortical and medullary architecture may suggest fibrous dysplasia.

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Unicameral Bone Cyst

A centrally located focal lucent lesion may be consistent with a unicameral bone cyst.

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Fibrous Cortical Defect or Nonossifying Fibroma

An eccentric cortical lesion is more typical of a fibrous cortical defect or nonossifying fibroma.

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Initial Stabilization

A displaced unstable fracture should be temporarily immobilized for comfort and to limit additional soft-tissue injury.

A traction splint or long-leg splint may be used depending on the child’s size, fracture level, and associated injuries.

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Treatment

Treatment depends primarily on age, body weight, fracture location, fracture stability, degree of comminution, associated injuries, and social circumstances.

Several methods provide excellent outcomes when used in appropriately selected patients.

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Physical Therapy

Formal physical therapy is particularly useful in children older than approximately 8–10 years.

Younger children generally regain motion and function rapidly without structured therapy.

Weight-bearing status depends on the treatment method and stage of fracture healing and should be directed by the treating orthopedic surgeon.

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Medication

Strong analgesics, including opioids, may be required during the early period after injury.

Pain generally decreases substantially after the first few weeks.

NSAID use should be individualized, particularly when there is concern about effects on fracture healing.

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Immediate Spica Casting

Immediate hip spica casting is commonly used in younger children, particularly those 6 years of age or younger and under approximately 32 kg.

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Technique

The cast extends from the trunk to the involved lower extremity and may include one or both legs.

It may be applied in the emergency department or operating room under sedation or anesthesia.

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Acceptable Alignment

In younger children, approximately 2.5 cm of shortening and 10–15° of angular deformity can often be accepted because of subsequent remodeling and femoral overgrowth.

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Healing

Union is usually achieved within approximately 6–8 weeks.

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Traction Followed by Spica Casting

Historically, children were often treated with 2–3 weeks of traction followed by application of a spica cast.

This method provides good control of length and alignment but requires prolonged hospitalization and is used much less frequently today.

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Flexible Intramedullary Nails

Flexible intramedullary nails are commonly used in children approximately 5–11 years old with appropriately located, relatively length-stable fractures.

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Limitations

They are less suitable for fractures very near the proximal or distal femur and for highly comminuted or length-unstable patterns.

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Postoperative Immobilization

Some children do not require a cast after flexible nailing.

Implants are often removed after healing, commonly several months later.

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External Fixation

External fixation is used mainly for severe open fractures, major soft-tissue injury, or selected unstable injuries.

It is typically used in children approximately 5–16 years of age.

Healing may be somewhat slower than with intramedullary fixation, and the risk of refracture after frame removal is higher.

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Plate Fixation

Plate fixation may be performed through an open or minimally invasive approach.

It is especially useful for comminuted, very proximal, very distal, or length-unstable fractures that are not ideal for flexible nails.

Plate failure is uncommon but possible.

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Rigid Intramedullary Nailing

Rigid intramedullary nails are generally reserved for older children and adolescents, commonly those older than about 10–11 years depending on size and skeletal maturity.

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Entry Point

Piriformis fossa entry should be avoided in skeletally immature patients because of the risk of injury to the femoral head blood supply and subsequent osteonecrosis.

Modern lateral trochanteric entry is preferred.

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Advantages

Rigid nails provide strong fixation and can allow earlier weight bearing in appropriately selected adolescents.

Implant removal may be considered in younger teenagers after healing.

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Follow-Up

Patients are commonly reviewed every 4–8 weeks until fracture healing is established.

Serial radiographs are usually required.

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Return to Sports

Sports and high-impact activity should be avoided until the fracture has healed adequately and strength and motion have recovered.

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Implant Removal

Flexible nails and some other implants are often removed after union.

The timing depends on implant type, symptoms, age, and surgeon preference.

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Long-Term Follow-Up

Follow-up may continue for up to approximately 2 years in younger children to monitor for overgrowth, limb-length discrepancy, or angular deformity.

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Referral for Physical Therapy

Physical therapy referral is appropriate when the child is not recovering expected range of motion, gait, or strength, or when special complications are present.

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Prognosis

Most children regain full function after treatment.

The pediatric femur has substantial healing and remodeling capacity, particularly in younger patients.

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Associated Knee Ligament Injury

Concomitant knee ligament injury can occasionally produce long-term impairment, especially in younger children.

The knee should therefore be examined both at the time of fracture stabilization and after healing, with MRI obtained if clinically indicated.

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Complications

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Nonunion

Nonunion is rare after closed pediatric femoral shaft fracture, occurring in less than approximately 1% of cases.

The rate is substantially higher in severe open fractures, historically around 10–20%.

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Malunion

Children tolerate more angular deformity than adults because of remodeling.

Approximately 15–20° of angulation may be acceptable proximally, while roughly 10° may be acceptable distally, depending on patient age and plane of deformity.

Remodeling is most reliable in children younger than approximately 10 years.

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Shortening

Up to approximately 2.5–3 cm of shortening may sometimes be accepted in younger children because subsequent overgrowth can compensate for part of the discrepancy.

Expected overgrowth is commonly around 1–1.5 cm.

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Persistent Limb-Length Discrepancy

If significant inequality remains, options such as contralateral epiphysiodesis or other limb-length procedures may be considered depending on remaining growth.

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Neurovascular Injury

Neurovascular injury is most commonly associated with open or high-energy fractures.

Femoral artery injury and thigh compartment syndrome are uncommon but serious complications.

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Infection

The risk of infection after operative treatment is low, historically around 1% in closed injuries, but rises substantially with open fractures and severe soft-tissue damage.

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Osteonecrosis

Osteonecrosis of the femoral head is a recognized complication of older-style rigid intramedullary nails inserted through the piriformis fossa.

This entry point should therefore be avoided in skeletally immature patients.

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Ligament Injury

Knee ligament injuries may coexist with the femur fracture and can be difficult to diagnose acutely.

The knee should be reassessed once the fracture is stable.

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Patient Monitoring

During the first 1–2 days, serial neurovascular examinations should be performed.

Monitoring should include distal perfusion, motor and sensory function, swelling, pain, and signs of compartment syndrome.

Subsequent visits should assess fracture alignment, callus formation, limb length, rotational alignment, knee function, and return of normal gait and activity.