INTRODUCTION

    Fractures of shaft of femur in children
account for approximately 1.6% of all fractures. These fractures can be treated
surgically or conservatively. Surgical treatment is more common in the age
group above six years. Elastic intramedullary nails have become the most
popular method of treatment of fracture shaft of femur in children(1)

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    Femoral shaft fractures are the most
incapacitating fractures in children. Conservative treatment needs
hospitalization for long time for traction followed by immobilization in hip
spica. This type of treatment is not well tolerated as well as near the end of
growth, good reduction is important because malunion is no longer correctable
by remodeling. Elastic Intramedullary Nailing considered the method of choice
for the treatment of fracture shaft of femur in children because it is
minimally invasive and gives good functional cosmetic results as well as low
risks of complications(2).

    
Elastic intramedullary nailing for treatment of fracture shaft of femur
in children has gained increasing popularity since its introduction in the 1970s. Few modifications have been made
to the original technique in the last years, which clarify the simplicity of
the technique. The unsatisfied results following the use of Elastic intramedullary
nailing are typically due to incorrect constructs, wrong indications and poor
surgeon skills. The initial indications for elastic intramedullary nailing
(ESIN) were restricted to children with polytrauma or head injury in whom
immobilization in spica or traction treatment were not practical. Now, its use
is extended to all shaft fractures of long bones in children. The indications
have been further expanded to metaphyseal fractures, comminuted fractures, and
pathological fractures(3).

   
Management of femoral shaft fractures in children using elastic
intramedullary nailing is reliable and minimally invasive, with low risk of
complications. Elastic intramedullary nailing can be used regardless of age,
body weight, site, and type of fracture. This technique has many advantages as,
it does not require postoperative cast, primary bone union with avoidance of
injury of epiphyseal growth plate, early weight bearing, and restore of limb
function(4).

   
 Angulation, mal-rotation, and shortening
are not well corrected with conservative treatment. Whatever the type of
treatment, the goals should be to stabilize the fracture, to correct the length
and alignment, to promote fracture union and to minimize complications and
discomfort for the child and family. The treatment of fracture shaft of femur
in children has shifted towards surgical treatment. Fixation of fracture shaft
of femur (SOF) in children by plate is a rigid fixation but it needs big
exposure that leads to increased blood loss and big scar formation, also it is
a load bearing device which can be complicated by refracture and can cause
growth disturbance. The elastic intramedullary nailing provides healthy
environment for healing of bone fractures with some motion leading to increased
callus formation(2).

   
Elastic intra medullary nailing is a successful choice in treatment of
femoral shaft fracture in children that enables early mobilization with
satisfactory functional results. Preoperative planning, intraoperative
technique, and postoperative care and follow up are essential in predicting
good results. The use of perioperative antibiotics is recommended to reduce the
risk of infection. During the process of cutting the ends of the nails, the
surgeon should be careful not to make the nails too prominent to decrease the
irritation of skin which lead to early removal of the nails. Parents should be
knew that mild complications are not uncommon, and that removal of the nails
may be necessary especially when symptomatic(5).     

 

 

 

 

 

 

 

AIM OF THE WORK

   
The aim of this thesis is to
evaluate the results of intramedullary nail fixation of fracture shaft of femur
in children using the elastic intramedullary nails.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

REVIEW OF LITERATURE

1.   
Anatomy of Pediatric Femur:

The femur is the longest and
strongest bone in the body and it is almost cylindrical in the major part of
its extent. The femur, as other long bones, is divided to a body, and upper and
lower extremities(6).

General Structures:

Epiphysis:

At birth the epiphysis is a
cartilaginous structure. The time for formation of the secondary ossification
center with in the epiphysis varies(7).

Ossification:

The femur has five ossification
centers:

One for the body, one for the head,
one for the greater trochanter, one for the lesser trochanter, and one for
distal part(Figer 1)(6).

The secondary ossification centers appear
in the epiphysis and separated from epiphyseal lines in the following order:

·       The distal part of the femur, at the ninth month of fetal life.

·       The head, at the end of first year of age.

·       The greater trochanter, at the fourth year of age.

·       The lesser trochanter, between 13 and 15 years of age(6).

    

 

                    Figure(1):
Ossification  centers of  the 
femur(6)

 

 

   
The epiphyses are united to the body in a reversed order of their
appearance, that are, the lesser trochanter is first joined, then the greater
trochanter, then the head, and the last one is the distal end, which united at
twentieth year of age(6).

  
 

Physis:

    
The physis is cartilaginous and can be identified as radiolucent gap
between the metaphysis and epiphysis. As the child grows, the physis becomes
thinner and it is easier to disrupt the growth by injury(7).

 

Metaphysis:

    
The metaphysis is the wide –shaped end of the long bones. It has
increased trabecular bone and it is wider than the corresponding part of the
shaft of the bone(7).

Proximal Femur:

    
The proximal part of femur consists of head, neck, and two trochanters.
The head is globular in shape and is directed upward, medial ward and little
forwards. The head articulates with the acetabulum to form the hip joint(8).

     The Neck is the process of the bone
that connecting the head of the femur to the shaft. The neck is projecting
upwards and medially from the shaft of femur. It is also projects some degree
forward, this forward projection is known as anteversion and is variable, but
on an average from 120-140(8).

     
The Greater Trochanter: Ossification in greater trochanter begins
at 4-7 years. Epiphysiodesis of greater trochanter occurs at 14-16 years of age(8).

     
There are many muscles attached to the greater trochanter as vastus
lateralis, gluteus medius, gluteus minimus, gemelli, and piriformis, there is
also overlying compression from Tensor fascia lata(8).

     
The Lesser Trochanter: It is smaller than greater trochanter, it
projects from posteromedial side of the femur, just inferior to the neck-shaft
junction. It is site of attachment for Iliopsoas tendon(8).

 

Femoral
Diaphysis:

       The shaft of the femur is cylindrical in
form. It is wider proximal than in mid shaft and more wider distally. It is
slightly arched, convex anteriorly and concave posteriorly. On the posterior
surface of the shaft there is longitudinal ridge called linea aspera
which provides musculofascial attachment(8).

 

Distal Femur:

     
It is characterized by the presence of the medial and lateral condyles
which articulates with proximal tibia and patella to form Knee joint.
The distal femoral epiphyseal plate is the largest and most actively growing
unit in the body, contributing almost 70% of the length of the femur and 40% of
entire length of the limb(9).

     

                                     Figure(2): Anatomy of the Femur(10).

 

 

Blood Supply of The Pediatric Femur:

      The shaft of the femur has a rich blood
supply that derived from endosteal and periosteal blood vessels. The endosteal
blood supply is from two nutrient vessels, that enter the medullary canal
posteromedially at the junction of the proximal and middle thirds and the
junction of distal and middle thirds of shaft of femur. The periosteal blood
supply comes from the large muscle of the thigh, that supplying outer third of
the cortex(11).

 

 

 

                     

                    
Figure(3): Blood supply of the femur(12)

 

Fascial Compartment of The Thigh:

       There are three fascial compartments in
thigh which divide and contain the muscles of the thigh. The fascia lata is the
deep fascia of the thigh that surrounds the muscles of the thigh and forms the
outer cover of the compartments. Internally the medial and lateral
intermuscular septa divide the muscle compartments to:

1.    The anterior compartment of the thigh
contains the Sartorius muscle and the four quadriceps ( the rectus femoris,
vastus lateralis, vastus intermedius, and vastus medialis).

They are supplied by the femoral nerve.

2.    The medial compartment contains pectineus,
external obturator, gracilis, and adductors( longus, brevis, and minimus ).
They are supplied by the obturator nerve.

3.    The posterior compartment contains the
hamstring muscles (biceps femoris, semitendinosis, semimembranosus muscles).
They are supplied by the sciatic nerve(13).

 

           
Figure(4): Fascial compartments of the thigh.(14).

 

 

 

 

 

 

2.  Biomechanics:

A.Biomechanics of fracture of femur of
children:

The bones of children are different from adult bones
in many ways. Children bones are softer than adult bones ( lower mineral
content and higher water content than adult bones), so they are more elastic
than adult bone. The periosteum of children bone is  thick and well vascularized(15).

According to these features of bone of children, there
are four types of fractures seen in children:

             
i.     Backle ( or torus ) fracture, occurs due to
axial compression of bone at diaphyseal metaphyseal junction.

          
ii.     Bowing fracture: diaphysis appears to be
bent without evidence of

fracture line.

       
iii.     Green Stick fracture: The fracture involves
one cortex and its periosteum.

         
iv.   Hair Line fracture: The fracture is often
not displaced and it is with in its periosteum(16).

 

 

 

In addition to these types of fractures there are many
other types that are also seen in adults, such as:

·             
Transverse fracture: caused by bending.

·             
Oblique fracture: caused by axial compression and
bending.

·                  
Spiral fracture: caused by rotational injury.

·             
Comminuted fracture (15).

 

     
Figure(5): Patterns of fractures of femur with different forces(15).

 

 

 

 

Certain Characteristics of Pediatric
Fractures:

1.   Pediatric fractures heal faster than adult
fractures.

2.   The periosteum is thicker than that of
adult and its blood supply is better.

3.   The fractures of children are more stable
than that of adult.

4.   Remodeling of bone occurs in pediatric but
not in adult.

5.   Healing of fractures in children may occur
with over growth resulting in lengthening of fractured bone(15).

 

 

Displacement of Fracture Fragments:

 

The displacement of fracture fragments is
affected by(17):

                                         
I.           
Direction of trauma causing fracture.

                                      
II.           
The effect of gravity.

                                  
III.           
Action of the muscles of the thigh.

 

I. Fracture of proximal third of the femur:

The short proximal fragment is flexed by the action of
iliopsoas muscle, abducted by the action of the gluteus medius, and externally
rotated by short rotators (obturator internus and externus) and gluteus
maximus.

The distal fragment is pulled proximally by hamstring
and quadriceps muscles. And adducted by adductors of the thigh. This action
leads to overriding of the fragments(18,19).

 

II. Fracture of middle third of the femur:

The displacements in fracture of the middle third are
not constant, but there is tendency for the proximal fragment to be flexed and
distal fragment to be displaced posteriorly(18,19).

 

III. Fracture of distal third of femur:

 

Gastrocnemius muscle is the main deforming muscle, it
originates from the posterior wall of the lower third of the femur. It pulls
the distal fragment posteriorly. The proximal fragment is displaced anteriorly
and distally(18,19).

 

 

 

 

 

 

 

 

 

 

 

Figure(6):
Displacement of  fracture fragments by
the action of the attached muscles(20).

 

 

 

 

 

 

B. Biomechanics of Elastic Nails:

     The use of elastic
intramedullary nails (ESIN) for fracture shaft of femur in children are
biological minimally invasive technique of fixation of fractures that aims to
achieve reduction and stabilization of fracture site(21).

     The biomechanical principle
of elastic nails is based on the symmetrical bracing action of the two nails
inserted through the metaphysis of the femur, each nail bears against the inner
surface of the bone at three points to get three point fixation(22,23).

      Stabilization is achieved
with elastic intramedullary nails that have been pre-contoured to provide some
elastic properties. This enables the nail to give sufficient stability to allow
early mobilization and partial weight bearing. So, elastic intramedullary nail
is a biological and child – comfortable method of fixation for different types
of fractures of shaft of femur in children(21,24).

      Elastic intramedullary nails
produce less unwanted effects on the healing of the fracture and the growth process
than other more invasive procedures(21).

      Elastic nails allow useful
forces like compression-traction force to act on the fracture site, also it
prevents the unwanted harmful forces as torsional and shearing forces which
reduce callus formation(24).

Stability Provided by Elastic Nails(21):

·      
Axial stability: The round force of the pre-bent nails tend
to reduce the fragments to the original position.

·      
Translation stability: Parallel nails with good cortical contact
prevent translation.

·      
Rotational stability:  Rotational
rebound force bring  the fragments back
to the correct position.

 

  

Figure(7): How elastic nail achieves axial, rotational, and
translational stability(21).

 

 

 

 

 

 

Figure(8):  Symmetrical 
action  of  both 
nails to achieve stability(21).

 

 

 

 

 

 

 

3.   Pediatric
Femoral Shaft Fracture:

 

Epidemiology:

    Fracture shaft of femur
account for 1-2% ( 1.6% )of all fractures in children. Males sustain this
fracture 25% more than females. There are two peaks of incidence, one peak
incidence at 2-3 years of age and the other peak in adolescence. The incidence
of fracture shaft of femur is decreased in late childhood because
the thickness of femoral cortex increases rapidly after 5 years of age(25).

    The annual rate  of incidence of all types of fracture of
femur was 26 per 100000 for all age groups, and boys are more affected than
girls(26).

 

Mechanism of
injury:

    Fracture of shaft of femur
that occurs in early childhood tend to be occurred due to low energy injury (
such as falls ). Because of weakness of the bone at this stage of age caused by
thin cortex of the bone and woven bone composition, less injury is required to
produce fracture(20).

     Children in older age group (
adolescent ) constitute the other peak of fracture shaft of femur. The injuries
are associated with higher energy injuries as road traffic accidents (RTA)(20).

     Pathological fractures of
shaft of femur are relatively rare in children but may occur in cases of generalized
osteopenia in infants or young children with osteogenesis imerfecta and
conditions as cerebralpalsy, myelomeningocele and bone tumours(27)

Classification of fracture:

 

     Fracture of shaft of femur in
are classified as(28):

(A). According to the morphology of fracture:

·      
Transverse, spiral, or oblique.

·      
Comminuted or non-comminuted (simple).

Figure(9):
Types of fracture shaft of femur(29).

    (B). Open
or Closed Fractures:

      Open fractures are classified according
to Gustilo’s  classification system.

Gustilo’s Classification of Open
Fracture(30):

Type I:  Wound is clean and less than 1cm.

Type II:  Wound from 1-10cm.

Type IIIa:

·    
Wound is more than
10cm.

·    
Adequate soft tissue
for coverage.

·    
Segmental and
comminuted fractures even if the wound is less than 10cm.

·    
Contaminated wounds.

Type IIIb:   The fracture is associated with extensive
periosteal stripping

                     and requires soft tissue
transfer.

Type IIIc:    The fracture is associated with vascular
injury.

 

                     Figure(10): Gustilo’s
classification of open fracture(31).

 

 

 

 

 

 

 

      AO Classification of fracture:

    An AO pediatric comprehensive
classification of long bone fracture had been developed. The diagnosis includes
the distinction between epiphyseal (E), metaphyseal (M), or diaphyseal (D)
fractures. The AO classification allows good documentation of fracture. A
complete mid shaft fracture of the femur has the following code: 32-D/3.1(32).                 

    Bone 3 = Femur

 
  Segment 2= 
Midshaft

 
  Type D = Diaphysis

    Child code 3 = Complete

    Severity code 1 = Simple(32).

Treatment of Fracture
Shaft of Femur:

      The fracture shaft of femur in children
can be treated by many methods depending on age of child(33).

      The traditional method of treatment of
fracture shaft of femur is traction followed by a spica cast(33).

      Commonly used methods are(33):

A.  Conservative
methods:

·      
Skin or skeletal
traction.

·      
Immediate hip spica.

·      
Traction followed by
spica.

 

B.  
Surgical methods:

·      
External fixation.

·      
Open reduction and
internal fixation.

·      
Intramedullary
nailing.

 

    Due to advantages of surgical treatment as
early mobilization and decreased period of hospitalization, the popularity of
surgical treatment is largely increased(34).

     Elastic Intramedullary Nailing:

    It is popular, less invasive technique for
treatment of fracture shaft of femur in children with low risk of complication
and short period of hospitalization(35).

 

 
  Indication of elastic nails(36):

Elastic nails can be used in
children with fracture shaft of femur if the fracture was:

·      
Transverse fracture.

·      
Short oblique
fracture.

·      
In children with
poly-trauma.

·      
Concomitant head
injury.

·      
In cases with minimum
comminution.

·      
Open fracture of type
A and B

 

 

 

  
Contraindications of elastic nails(36):

Elastic nails can not be used in
the following cases:

·      
Long spiral
fractures.

·      
Highly comminuted
fractures.

·      
Patients with over
weight.

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