Paediatric Orthopaedics

A Self-directed Learning PackageMater Children’s Emergency DepartmentBrady / Reilly updated 2011

Fractures in Children

• Children’s fractures are unique due to their immature skeleton.

• This module will take you through some common and important fractures, helping you to recognise and describe them.

• You will also learn about fractures and conditions that are less common, but very important not to miss.

Common FracturesThe sites of the most common fractures vary with each age group. [Pictures from Thornton, Gill

“Children’s Fractures”

Saunders 1999]

Epiphysis

Epiphyseal plate (Physis)

Metaphysis

Diaphysis

Parts of a Long BoneYou will need to know these for describing fractures in children.

Salter-Harris Classification

Describing FracturesWhen describing a fracture, follow the following formula:

1. open or closed2. bone/s involved3 .part of bone involved – midshaft/distal third/metaphysis/epiphysis4. type of fracture –bowing

-buckle-greenstick (with or w/o cortical or periosteal breach)-transverse-oblique-spiral-comminuted

5. displacement – direction of displacement of distal fragment relative to proximal fragment eg palmar or volar/dorsal, anterior/posterior

6. angulation – the angle the distal fragment makes with the main axis of the bone eg ‘distal fragment angulated 20 degrees posteriorly’

7. Presence or absence of associated dislocation8. Presence or absence of associated neurovascular injury

For example…This is a closed greenstick-type fracture of the distal radius with minimal displacement and 10 degrees of dorsal angulation of the distal fragment.

10

Example 2

This is a closed transverse fracture of the distal third of the radius and ulna. The distal fragment of the ulnar fracture is displaced dorsally and both distal fragments are angulated to approximately 30 degrees.

Remember that displacement and angulation are different – displacement means that there is lateral translation or distraction or shortening of the two fracture fragments relative to one another, angulation means they are bent!

30

Example 3

Dislocations without fractures are described in a similar way, but instead of the bone, it is the involved joint that is described.

This is a closed dislocation of the metacarpophalangeal joint of the thumb with dorsal displacement of the distal fragment/proximal phalanx.

Upper Limb Fractures

We will now work through the most important upper limb fractures:

• Supracondylar fracture• Dislocated elbow• Medial epicondyle fracture• Fractured radius and ulna • Distal radial fracture• Fractured metacarpals• Fractured scaphoid• Monteggia fracture-dislocation

Supracondylar Fracture

• Unique to children under 10, rare in adults• Most common elbow fracture in children• Caused by a fall on the outstretched hand,

with hyperextension of the elbow• The fracture is at the lower end of the

humerus, above the medial and lateral epicondyles

• May be radiologically subtle• Missed fractures may result in permanent

neurovascular injuries or elbow deformity

Supracondylar fractures• Supracondylar fractures are important because of

the associated high incidence of nerve and vessel injury

• The brachial artery and the median, radial and ulnar nerves can all be kinked or torn by the fracture fragment as they run in front of and behind the elbow joint

• All must be clinically evaluated and documented in every patient

• Brachial artery injury may manifest as delayed capillary refill, a cold pale hand or absent pulses at the wrist

• Median nerve injury (most common) may manifest as inability to flex the interphalangeal joint of the thumb or sensory loss

• To diagnose a supracondylar fracture it is important to know the Elbow Rules

Cubital fossa nerves and artery

Radial N S: dorsal forearm

M: Finger gun gestureMedian N S: radial palm M: OK gestureUlnar N S: ulnar forearm

M: Cross fingersBrachial A: radial and

ulnar pulses and hand perfusion

Elbow Rule #1A line drawn through the radial head always

intersects the capitellum in both AP and lateral views

Radial head

capitellum

capitellum

Radial head

Every time you see an elbow xray, just think to yourself:

radial headcapitellum, radial headcapitellum.

Elbow Rule #2A line drawn along the anterior aspect of the humerus (the Anterior Humeral Line) should intersect the middle third of the capitellum.

Capitellum

Elbow Rule #3A posterior fat pad (a black lucency posterior to the distal humerus), if visible in a true lateral film, indicates a fracture.

Normal elbow Supracondylar fracture

Posterior fat padNo fat pad

Radiographic Findings

In most supracondylar fractures, the anterior humeral line does not pass through the middle third of the capitellum, but anterior to it.

In addition, there is a visible posterior fat pad

The radial head and the capitellum are usually still aligned, because the fracture is above this level

In this fracture there is posterior angulation and displacement of the distal fragment

Supracondylar Fracture

Anterior humeral line

This xray shows a suprandylar fracture with posterior displacement, angulation and rotation of the distal fragment.

Dislocated ElbowGenerally, this is not a tricky diagnosis clinically or radiologically. The xray shows a dislocation of the right elbow joint with posterior displacement of the radius and ulna.

Medial Epicondyle Injuries

•The medial epicondyle is the third ossification centre in the elbow, becoming visible at around 6 years of age.

•Injuries usually occur when the elbow is forcibly abducted, and the medial epicondyle is pulled away from the lower end of the humerus by the ulnar collateral ligament.

•On AP view, the medial epicondyle should lie within 3mm of the distal humerus. If it is further away than this, it is likely to have been avulsed.

•On lateral view the medial epicondyle should not be visible, as it is obscured by the capitellum. If you can see it in a true lateral, it’s not in the right place.

•If in doubt, xray the opposite side to compare

Medial epicondyle fracture

Medial epicondyle

Medial Epicondyle Fracture

Normal elbow

Gap less than 3mm

Extensive soft tissue swelling Gap >3mmAvulsed medial epicondyle

Fractured Radius and UlnaThese fractures may be very obvious clinically and

radiologically. This xray shows fractures of the mid-shaft of the radius and ulna with dorsal angulation of 80 degrees with minimal displacement of the distal fragments because the dorsal cortex and periosteum of the bones are still intact.

80

These fractures can also be very subtle – shown here is a greenstick fracture of the distal radius with ulnar bowing – a fracture type unique to children.

Radial greenstick fracture

Radial greenstick fracture

Ulnar bowing

Distal Radial FractureAgain, these fractures may be very obvious, as shown at left, or just a subtle buckle (torus) fracture

Fractured Fifth Metacarpal

Epiphyseal plate

Fracture

Fractured Scaphoid

Scaphoid fractures are uncommon in children

When they do occur, it is in the more skeletally mature child (usually greater than 10 years)

Fracture across waist of scaphoid

Monteggia Fracture-dislocation

In its most common variant, this is a fracture of the distal ulna associated with a dislocation of the radial head at the elbow. This is an uncommon injury, but the radial head dislocation is often missed, making it important to know what to look for.

Generally, the ulnar fracture is obvious. Due to the close relationship between radius and ulna, the resultant shortening should prompt a search for a balancing radial defect.

The radial head dislocation becomes apparent if you follow the ‘radial headcapitellum’ rule.

This particular fracture-dislocation is usually treated with closed reduction under general anaesthesia. Other variations of disruption/dislocation occur.

Monteggia Fracture-dislocation

Ulnar fracture

Capitellum

Radial head

Lower Limb Fractures

• Fractured femur• Fractured tibial spine• Fractured tibia• Ankle fractures• Slipped upper femoral epiphysis

(SUFE)

Fractured FemurThis is usually an unequivocal diagnosis. This xray shows a transverse fracture of the midshaft of the left femur with lateral displacement of the distal fragment, but with minimal angulation. That is, the distal fragment has moved sideways from the fracture site but has not angled away from the long axis of the bone.

Fractured Tibial SpineThis fracture is the paediatric equivalent of the anterior cruciate ligament tears seen in adults. Because ligaments have maximal tensile strength in childhood, the bone at the site of insertion fractures (or avulses) first. Because these fractures are subtle on AP view, they can be missed. However, as with all joints, an effusion after trauma in the paediatric population usually indicates significant, often bony disruption and should always be referred to the orthopaedic team.

Fracture line just visible on AP view

Fracture line more apparent on lateral

Fractured Tibia

Spiral fractures of the tibia are relatively common in toddlers as they are learning to walk. As the child gets older, however, considerably more force is required to fracture the tibia.

Note that the fracture is quite difficult to see on the lateral film. Remember all fractures require a minimum of two views, and the joints above and below need to be visualised.

Ankle FracturesWith all ankle fractures, remember that the tibia and fibula often fracture together (like the radius and ulna) and a fracture in one should prompt a thorough search for a fracture in the other.

The fibula in particular may fracture at a site distant from the site of the tibial fracture. The entire length of the fibula needs to be xrayed so as not to miss this.

This fracture is described on the next slide.

Ankle FracturesThis fracture looks difficult to describe, but if you follow the formula it makes it easier.

This is a closed fracture of the distal left tibia and fibula. The tibial fracture extends through the epiphyseal plate and into the metaphysis of the tibia (Salter Harris type II fracture). The distal fragment is displaced laterally and is angulated to 30 degrees.

The fibula shows two greenstick fractures of the distal shaft. The fractures are not displaced but are angulated to 30 degrees.

30

30

Tibial fracture line

Fibular fracture sites

Ankle Fractures

This is a Tillaux fracture of the

ankle –the adolescent equivalent of an avulsion fracture of the medial malleolus in a child (again, as the ligaments are so strong the bone fractures first).

Without knowing the eponymous name for it though, you could describe it as a closed fracture of the medial distal left tibial epiphysis with minimal displacement and no angulation. The fracture line extends from the epiphyseal plate to the tibio-talar joint space.epiphysis

Fracture line

Slipped Upper Femoral Epiphysis = SUFE

Slipped upper femoral epiphysis is a condition where the there is displacement of the femoral head relative to the femoral neck through the epiphyseal plate. The underlying multi-factorial vulnerability to shear stress may cause gradual cumulative slippage, or the epiphysis may slip acutely. It is the most common hip problem of adolescence.

This disorder is important because early diagnosis improves outcome. Initial missed diagnosis is the rule, with the average time to diagnosis of 6 to 10 months.

SUFE eventually occurs in the opposite hip in 60% of patients.Obese adolescent boys are most at risk, but SUFE can occur

in any adolescent (8-15 years).Clinically there will be hip, knee or groin pain with or without a

history of trauma. In some 50% of patients, hip pain never develops and the primary symptom is isolated knee pain referred from the hip.

Treatment is usually surgical.

SUFEThe radiologic findings can be subtle but become more obvious when the correct views are obtained. While the AP can appear normal, the head should “mushroom” out over the neck. As you can see in this case the frog-leg lateral clearly shows the slippage of the femoral head t the level of the epiphyseal plate.

AP view Frog-leg lateral view

Cervical Spine Injuries

You will learn about:• How to assess xrays of the cervical spine• Teardrop fracture• Jefferson fracture

Cervical Spine - 7 bones and 3 views

2

3

4

5

6

7

1

T1

A minimum of three views showing all seven cervical vertebra is the minimum requirement for an adequate assessment of the cervical spine. The three views are AP, lateral down to C7/T1 junction, and an open mouth peg view.

Cervical Spine Imaging Note that for optimal neutral positioning in the

supine position, children under 10 with suspected spinal injury must have a foam thoracic elevation device (TED) inserted as part of routine spinal immobilisation [to counter-balance their large heads].

Without this, hyperflexion and false positive radiological findings, such as increased prevertebral soft tissue thickening and pseudo-subluxation, are more common.

Pandie et al 2010 BMJ

Cervical Spine- the 4 lines

Anterior vertebral line

Posterior vertebral line

Spinous process line

Spino-laminar line

Start with the lateral. Trace the 4 lines below, looking for any part of the vertebrae that are out of alignment. The lines become more curved as you go from anterior to posterior.

Cervical spine – the soft tissues

Next look at the soft tissues.

The maximal allowable width of the pre-vertebral soft tissue space is:

- one half the vertebral body width from C1 to C4

- one whole vertebral body width from C4 to C7

Increased width of the pre-vertebral space of a properly positioned cervical spine suggests swelling, eg from a fracture or ligamentous injury.

Cervical Spine – vertebral bodies

The next step is to trace around individual vertebral bodies in turn, looking for irregularities in the usual rectangular shape.

Look particularly for wedge or compression fractures, with irregular loss of height, or teardrop fractures of the anterior inferior corner of the vertebral body. These are important because although small, they indicate significant ligamentous injury and hence potential instability.

Teardrop Fracture

The next thing to assess on a lateral film is the pre-dental space – that is, the space between the anterior border of the peg, and the anterior arch of C1. Anything greater than 5mm (child or adult) is abnormal and suggests instability of the transverse ligament

Cervical spine - AP

Next assess the AP view.

The main things to look for in this view are:

-that the spinous processes line up

-that the vertebral bodies are symmetrical and have no obvious fracture

-that the vertebrae are evenly spaced

Cervical Spine - peg

Odontoid process

Body of C2

Lateral masses of C1

Lastly assess the peg view. Look for a well-centred film with the peg lining up with the gap between the front incisors. This film is slightly rotated.Next look at the space either side of the peg – this should be symmetrical.Then look at the outside edge of the lateral masses of C1 – this should line up with the outside edge of C2.

C1/C2 FractureNote that the anterior and posterior vertebral lines are abnormal, and the soft tissue spaces very widened. The peg has fractured and has tilted forward, as has the anterior arch of C1. This will cause angulation and compression of the spinal cord at the level of C2.

Jefferson Fracture

A Jefferson fracture is a burst fracture of C1. Think of C1 as peppermint lifesaver – it is impossible to break it in only one place. The ring will always break in at least 2 places. This fracture occurs due to compression – a fall from a height, or hitting the head on the roof of the car in a motor vehicle accident. This film shows a widened pre-dental space from an associated ligamentous instability.

Jefferson FractureOn the peg view, it is apparent that the space either side of the peg is widened and asymmetrical. In addition, the lateral masses do not align with the lateral borders of C2 – they have been laterally displaced.

Well done! You’re finished.