Hip Fracture in the Child

By admin Last updated Jan 30, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Hip Fracture in the Child

Hip Fracture in the Child

Paul D. Sponseller MD

Basics

Description

Fracture of the femoral neck, in the intertrochanteric or subtrochanteric region
Classification: Delbet system as popularized by Colonna (1):
- Type I
  - Transphyseal separation (femoral head separates from neck through the growth plate)
  - Can be nondisplaced (widened physis), displaced, or dislocated
  - Least common type
  - Occurs in young children
  - Many patients have dislocation of the femoral head from the acetabulum.
- Type II:
  - Transcervical
- Type III:
  - Cervicotrochanteric
- Type IV:
  - Intertrochanteric
Initial displacement seems to affect the risk of osteonecrosis most.
Anatomy:
- Blood supply:
  - At birth, the blood supply to the femoral
    head travels through the metaphyseal vessels traversing the neck,
    deriving from the medial and lateral femoral circumflex arteries.
  - The growth plate of the proximal femur prevents these vessels from penetrating the femoral head.
  - By 4 years of age, the contribution by
    the metaphyseal blood supply is negligible, and the medial femoral
    circumflex artery provides the major blood supply to the head.
  - Capsulotomy of the hip does not damage
    the femoral head’s blood supply unless the procedure violates the
    intertrochanteric notch or damages the posterosuperior or
    posteroinferior vessels along the femoral neck.
  - The ligamentum teres contributes only a small percentage of the blood supply to the femoral head.
- Bone:
  - ~1/2 of pediatric hip fractures are nondisplaced.
  - If the fracture is displaced, it is likely to be unstable.

Epidemiology

Incidence

This injury accounts for <1% of all pediatric fractures, far less than the percentage in adults (2) because the bone is so strong.

Etiology

75% of pediatric hip fractures are caused by severe trauma and high-velocity injuries (e.g., motor vehicle accidents, falls).
The remainder result from some underlying
pathologic process (e.g., fracture through a unicameral bone cyst,
aneurysmal bone cyst, or fibrous dysplasia) or child abuse.

Associated Conditions

Infants:
- Suspect child abuse.
- If the injury is a result of an automobile accident, look for associated injuries.
Children:
- Great force is required.
- Look for associated injuries.
Adolescents:
- Acute fracture occurs through the growth
  plate (SCFE), or it is a pathologic slip (look for hypothyroidism,
  renal osteodystrophy).

Diagnosis

Signs and Symptoms

Sudden pain in the hip
Inability to stand or walk
Swelling in the inguinal crease, gluteal, proximal thigh
Limb held in external rotation, flexion, and adduction to relieve capsular distention
Resistance to any movement: Active hip
motion is impossible if the fracture is displaced, and passive motion
(especially flexion, abduction, and internal rotation) is restricted
and painful.
Pain and sometimes crepitus with hip motion
Pseudoparalysis of the affected limb in infants
Extremity possibly shortened 1–2 cm

Physical Exam

Most children with femoral neck fractures are in extreme pain.
For the minority who do not have a complete fracture, pain is elicited most by internal rotation, abduction, and flexion.

Tests

Imaging

AP and lateral radiographic views of the hip may show upward and lateral displacement of the femoral shaft.
CT can be helpful for determining the direction of the femoral head dislocation.
In newborns, ultrasound may be helpful in showing a femoral neck fracture.

Differential Diagnosis

SCFE
Developmental coxa vara (this condition has a vertical cleft in the femoral neck)

Treatment

General Measures

Treatment is aimed at achieving anatomic reduction, either open or closed.
Use smooth PINS or cannulated 4.0–4.5-mm
screws in children ~2–6 years old and cannulated 6.5–7.0-mm screws in
children ≥7 years old.
Usually, a spica cast is used
postoperatively because the smaller diameter of the femoral neck in
these younger patients limits the size and number of screws that can be
placed.
If the injury is type I and one must cross the physis, use smooth PINS followed by a spica cast.
For types II–IV, screws should not cross
the physis unless the fracture cannot be stabilized without doing so;
the physis of the proximal femur grows only 3 mm per year, so fear of
limb-length discrepancy should not compromise fixation.
If the hip is dislocated, make one attempt at closed reduction, then try open reduction.
If open reduction is attempted, the
surgical approach should be in the direction of the dislocation:
Posterior for posterior dislocation, anterior for anterior dislocation.

Surgery

Type I:
- Without dislocation:
  - Gentle closed or open reduction and fixation with a screw or a pin
- With dislocation:
  - Nearly 100% develop osteonecrosis, and 80% are at risk for developing degenerative joint disease.
  - Attempt gentle closed reduction using
    longitudinal traction, abduction, and internal rotation; if that is
    unsuccessful, try immediate open reduction and pin fixation.
Type II:
- Most common type
- Most fractures are displaced.
- Osteonecrosis in ~50% (displaced fractures at higher risk than nondisplaced)
- Closed or open reduction and pin or screw fixation for both displaced and nondisplaced fractures
Type III:
- 2nd most common type
- Osteonecrosis in 25%
- Displaced:
  - Gentle closed reduction or open reduction and internal fixation
- Nondisplaced:
  - Abduction spica cast possibly adequate in
    children <8 years old, although late displacement or coxa vara is
    possible; close observation is necessary.

P.189

Type IV:
- Open reduction and internal fixation with pediatric hip compression screw fixation.
Surgical pearls:
- Use a fluoroscopy table or a fracture table and an image intensifier.
- A straight lateral approach is used.
  - If intracapsular open reduction is
    needed, types II and III can be via a proximal extension of the tensor
    fascia lata–gluteus interval.
  - Type I and high type II: Use the anterior iliofemoral approach
- The reduction maneuver includes traction and internal rotation.
- Unacceptable reduction is indicated by a varus position or excessive displacement on AP and lateral views.
- No displacement of the width of the femoral neck should be accepted because additional varus angulation is likely.
- Instrumentation:
  - Types I, II, and III: Use 2–3 cannulated screws of appropriate size for age (3).
  - Type IV: Use a hip compression screw device with a side plate.
- Nonoperative option: Reduce with 3–6
  weeks of skeletal traction and then immobilization in hip abduction
  cast for a total treatment course of 12 weeks.
- Patient age:
  - For patients 7–12 years old, use
    pediatric hip screw fixation, followed by hip spica cast for 8–12 weeks
    after surgery, depending on the stability of fixation.
  - For patients ≥13 years old, treat as an
    adult: The hip screw and side plate may cross the physis, and no
    postoperative immobilization is required.
- Timing of surgery:
  - Within 24 hours
  - Type I fracture with dislocation requires immediate treatment
  - No conclusive data on the effect of timing on osteonecrosis
- Implant removal:
  - No absolute time limit exists for removal of hardware.
  - However, it usually is removed within
    12–18 months of injury, if the fracture has healed, to prevent bony
    overgrowth or refracture at the base of the implant.

Pediatric Considerations

Neonatal epiphysiolysis:
- If recognized initially, use skin traction to restore alignment.
- If recognized after callus formation is visible radiographically, use simple immobilization.
- Open surgical reduction is not advised
  because these injuries in newborns tend to remodel if the physis does
  not close prematurely.
- Close observation is necessary; a low incidence of osteonecrosis is noted.

Follow-up

Prognosis

The outcome is determined by the degree of damage to the blood supply.

Complications

Complications occur in as many as 60% of patients (3,4).
Most complications of pediatric hip fractures are influenced by the changing blood supply of the proximal femoral epiphysis.
AVN (osteonecrosis):
- Most common, most devastating complication
- May affect epiphysis, both epiphysis and metaphysis, or metaphysis alone
- Develops in 42% of hip fractures in children within 9–12 months after injury (4):
  - Type I, nearly 100%
  - Type II, 52%
  - Type III, 27%
  - Type IV, 14%
- Initial displacement of the fracture, fracture types I and II, and age (>10 years) are associated with increased risk.
- Treatment:
  - Motion and containment are maintained.
  - Osteotomies to rotate the less-deformed
    or less-involved portion into the weightbearing region may improve
    congruity and symptoms.
- Ratliff (5) classification of osteonecrosis in children, with current commentary (3,4):
  - Type I: Total involvement and collapse of
    the femoral head; worst prognosis; most common injury; injury to all
    lateral epiphyseal vessels
  - Type II: Involvement of a portion of the
    epiphysis accompanied by minimal collapse of the femoral head;
    localized injury to the anterolateral femoral head
  - Type III: Increased sclerosis of the
    femoral neck from the fracture line to the physis, but sparing of the
    femoral head; injury to the metaphyseal vessels
Nonunion:
- Occurs in 5–8% of fractures (similar to the risk in adults) (3,4).
- Closed treatment of types II and III is associated with an increased incidence of coxa vara and nonunion (3,4).
- Internal fixation after acceptable
  reduction decreases the incidence of nonunion because it does not allow
  varus angulation or late displacement.
Coxa vara:
- Secondary to growth-arrest of the proximal femoral physis or to malunion
- If the neck shaft angle is <110°, it will not correct with remodeling.
- Subtrochanteric valgus osteotomy, bone
  grafting, and internal fixation can give excellent long-term results if
  no osteonecrosis is present.
Premature closure of the physis:
- A slight leg-length inequality results.
- It occurs even without internal fixation crossing the physis.
- Closure often is related to osteonecrosis.
- The proximal femoral physis contributes
  growth of only 3 mm per year (~15% of total length of extremity) but,
  if osteonecrosis and premature closure occur, a substantial limb-length
  discrepancy can develop.
- Follow with yearly scanograms and hand
  and wrist radiographs for bone age, with plotting on Moseley charts;
  consider epiphysiodesis of contralateral limb if substantial
  limb-length inequality develops.
- In rare cases, symptomatic trochanteric overgrowth in children >8 years old can require trochanteric transfer.

References

1. Colonna PC. Fracture of the neck of the femur in children. Am J Surg 1929;7:793–797.

2. Pring ME, Rang M, Wenger DR. Pelvis and hip. In: Rang M, Pring ME, Wenger DR, eds. Rang’s Children’s Fractures, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2005:165–179.

3. Cheng JCY, Tang N. Decompression and stable internal fixation of femoral neck fractures in children can affect the outcome. J Pediatr Orthop 1999;19:338–343.

4. Morsy HA. Complications of fracture of the neck of the femur in children. A long-term follow-up study. Injury 2001;32:45–51.

5. Ratliff AHC. Fractures of the neck of the femur in children. J Bone Joint Surg 1962;44B:528–542.

Additional Reading

Gray DW. Trauma to the hip and femur in children. In: Sponseller PD, ed. Orthopaedic Knowledge Update: Pediatrics 2. Rosemont, IL: American Academy of Orthopaedic Surgeons, 2002:81–91.

Miscellaneous

Codes

ICD9-CM

820.08 Pediatric hip fracture

FAQ

Q: What is the most serious complication of femoral neck fracture in children?

A: AVN, which is an increased risk with greater displacement and with more proximal fracture.