Soft Tissue and Bony Injuries in Children

Some mixed adult and paediatric emergency department will see around 30% of attendances in the paediatric age range.

Approximately 50% of these attendances will be with trauma and skeletal injuries, with fractures accounting for around 15% of those.

Approximately 15% of these represent physeal (growth plate) injuries [1]. This approximates to one patient per day in the average sized District General Hospital.

Bone Characteristics

Fractures in children have some unique characteristics. The psychological and physical trauma aside, children also need to cope with any effects of the trauma on their future growth. The biomechanical characteristics of the growing skeleton are different [2].

Childrens bones:

• Are less brittle, more malleable
• Allow a plastic type of bowing injury

This may lead to:

A subtle bow to a bone (plastic deformation)

Fig 1: Plastic bowing fracture

An incomplete fracture (greenstick) fracture

Fig 2: Greenstick fracture

Buckle fractures

Fig 3: Buckle fracture

All occur more often in children than adults.

Other Considerations

Comminuted fractures are less common in children because:

• A childs ligaments are relatively lax compared to an adults, but they are stronger. Sprains are therefore unusual
• Instead, growth plate fractures and avulsion fractures near the ligamentous insertions are more common

The bone is more biologically active with a thick vascular periosteum so:

• Bone healing is faster in children
• Complications affecting bone healing are rarer than in adults
• The thicker periosteum usually remains intact on the concave side of the fracture
• Childrens bones remodel to a greater extent than adults do, and therefore a greater amount of angulation and displacement is acceptable in children.
• The exception to this is with intra-articular fractures where angulation or displacement are never acceptable.
• Rotational deformity does not correct readily in the young child and should always be avoided.

More biologically active bone and thick vascular periosteum has several implications:

• Decreases the amount of displacement of fractures
• Is probably a factor in the lower incidence of open fractures in children
• Allows manipulation under anaesthetic (MUA) to be achieved relatively easily without over-correction
• Also helps to stabilise any fracture reduction
• Stiffness of joints after immobilisation is less of a problem in children than in adults, partly because immobilisation is needed for shorter periods

Growth Plate Fractures

Growth plate fractures are specific injuries that occur through or near a childs growth plate (physis):

• Injuries are usually caused by torsion at the physeal region
• The physis is a cartilaginous disc between the epiphysis and metaphysis and is a weak spot
• Complications of physeal injuries include physeal arrest and limb length discrepancies
• Trauma is the most common cause of physeal arrest and the reason for it is that a bridge of bone (physeal bar) forms between the metaphysis and epiphysis
• Peripheral bars (most common pattern) lead to angular deformities

For these reasons physeal fractures are closely managed to ensure the child has adequate bone growth during and after the healing of the injury.

Salter-Harris Classification

This physeal fracture classification system was first described in 1963 by Salter and Harris [3].

Type I

Type I – transverse fracture through the physis. The epiphysis separates completely from the metaphysis.

Fig 1a: Type I transverse fracture

Fig 1b: Slipped Upper Femoral Epiphysis (SUFE) on the right in this case, which is a form of SH I injury

Fig 1c: A severe slip on the left

Type II

Type II – fracture through the physis with a detached triangular metaphyseal fragment. This is the most common type of physeal injury seen.

Fig 2a: Type II fracture through the physis with a detached triangular metaphyseal fragment

Fig 2b: SH II distal tibia

Type III

Type III – a fracture through the physis and then entering the joint through a fracture of the epiphysis. This is therefore an intra-articular fracture but it is very rare.

Fig 3a: Type III fracture through the physis and then entering the joint through a fracture of the epiphysis

Fig 3b: SH III distal tibia

Type IV

Type IV – a fracture through the epiphysis, physis and metaphysis involving all three areas and being again intra-articular.

Fig 4a: Type IV fracture through the epiphysis, physis and metaphysis

Fig 4b: SH IV distal tibia

Type V

Type V – crush injury of the physis. There may be very little evidence of this on initial x-ray but the damaged physis means abnormal appearances months or years later as the bone growth has arrested. This is rare.

Fig 5: Type V crush injury of the physis

S.A.L.T.R

The classification is numerically based upon a worsening severity such that type I and II have an excellent prognosis, although complete or partial growth arrest may occur in displaced fractures.

The excellent prognosis is due to the fact that the germinal layer is usually left intact so that growth disturbance is uncommon.

Types III and IV have a worse prognosis, as growth arrest and angular deformity are common problems. Involvement of the germinal layer make growth disturbance and functional impairment more likely if not managed correctly.

Additionally special attention should be paid to types III and IV because of the intra-articular component.

Type V fractures have poor prognosis. This crushing type of injury was not originally described by Salter and Harris. It is rare and has a poor prognosis due to disruption of the blood supply to the epiphysis.

Unfortunately, this is usually diagnosed retrospectively when limb deformity becomes apparent.

Learning bite

Children have physes and any injury involving this region must be treated carefully in case of later growth disturbance. The physes are weak links in the growing skeleton and account for the difference between the location of fractures in children and adults.

All these biomechanical properties change with age and there are characteristic injury patterns for different age groups [4]. For example, a fall on the outstretched hand:

The risk of a child sustaining a fracture with a given amount of force is no different from adults. The pattern of injury that is sustained (buckle fractures, torus fractures, greenstick fractures) is different but a full history of mechanism of injury, height fallen, force sustained and degrees of rotation, etc, should always be ascertained, just as with adults.

The hallmark features for the presence of a fracture are the same as in adults. These include:

• Bony tenderness
• Crepitus
• Loss of function
• Deformity

Swelling is often seen with sprains or simple soft tissue injuries and is not diagnostic. If in any real doubt as to the presence of fracture or not then x-ray should be obtained.

Sprains

A sprain in an adult is a tear, or stretch, of a ligament:

• Most common around the ankle though may occur in the shoulder, knee, wrist or fingers
• Less common in children because the developing childs ligaments are very strong and relatively lax
• Trauma tends to cause damage at the bony attachment of the ligament which is often around the physeal plate area

Learning bite

The Ottawa ankle rules, used in adults to distinguish sprains from fractures, apply to children down to the age of 5 years and have been validated for such use in an ED setting [5].

The Ottawa ankle rules

Ankle X-ray is only required if there is any pain in the malleolar zone and any one of the following:

• Bone tenderness along the distal 6 cm of the posterior edge of the tibia or tip of the medial malleolus, OR
• Bone tenderness along the distal 6 cm of the posterior edge of the fibula or tip of the lateral malleolus, OR
• An inability to bear weight both immediately and in the emergency department for four steps.
• Additionally, the Ottawa ankle rules indicate whether a foot X-ray series is required. It states that it is indicated if there is any pain in the midfoot zone and any one of the following:
• Bone tenderness at the base of the fifth metatarsal (for foot injuries), OR
• Bone tenderness at the navicular bone (for foot injuries), OR
• An inability to bear weight both immediately and in the emergency department for four steps.

Certain groups are excluded, in particular pregnant women, and those with diminished ability to follow the test (for example due to head injury or intoxication). Several studies strongly support the use of the Ottawa Ankle Rules in children over 6 (98.5% sensitivity);[2] however, their usefulness in younger children has not yet been thoroughly examined.

Greenstick Fractures

A greenstick fracture is an incomplete fracture of the bone, with the cortex disrupted on one side but intact on the other. It is likened to the effect seen when a young green branch is snapped but only breaks on one side.

The break occurs on the outer side of the bend (tension) while the inside remains in continuity (in compression).

Depending on the degree of bend, the greenstick fracture must be bent back into a proper position (reduced) and then held in that position, generally by plaster of paris fixation.

Greenstick fractures can take a long time to heal because they tend to occur in the middle, slower growing part of the bone, whereas buckle fractures tend to occur towards the physes and will heal faster.

Clinical signs and symptoms may be subtle, greenstick fracture may be evident on x-ray only as a small irregularity and is often only visible in one plane.

Even when these fractures are moderately angulated reduction is relatively simple, as the strong cortex holds while the fracture is manipulated back to a normal position, and the intact cortex allows maintenance of a good position.

Buckle Fractures

The word torus is derived from the Latin word tori meaning swelling. Buckle fractures or torus fractures are extremely common injuries.

With softer bones, one side of the bone may buckle upon itself without disrupting the cortex of the other side.

Buckle fracture of the distal radius

This AP view shows a small kink, or buckle, in the cortices on either side of the affected bone. The lateral, however, shows that the cortical breach is isolated to just the dorsal surface. (Click on the image to enlarge).

Immobilisation in POP is advisable for pain relief.

Some centres use simple wrist splintage to manage distal radial buckle fractures of the type seen on Image 1 (no ulnar involvement).

It has been shown to be safe to manage these conservatively, with no fracture clinic follow up, such is the nature of the remodelling and long term result.

Buckles can occur almost anywhere.

Fig 2: Distal femoral buckle	Fig 3: Proximal tibial buckle

Injuries unique to children include the following:

Pulled elbow

A straight pull on the arm of a child under the age of 4 years, if forceful enough, is likely to result in a pulled elbow.

• This is unique to children because the relatively small, immature radial head is able to sublux under the relatively lax annular ligament
• Classic presentation is with the arm usually held straight or slightly flexed and resisting passive movements of flexion but particularly pronation and supination
• A simple manoeuvre reduces the subluxation without the need for any investigation
• If x-rayed, the elbow will appear normal. A large gap is apparent between the epiphyses of the proximal radius and the capitellum, normally because they are not fully ossified
• Children grow out of this condition as the radial head develops and it is said to be very unusual after the age of 4 years, and not to be seen at all after the age of 6 years

Toddlers fracture

This is unique to children due to the mechanism of injury and soft malleable bone. The toddler, still learning to walk, is relatively unsteady on the feet. A fall with the foot planted firmly on the floor will lead to a rotational force as the child falls. Management of toddler fracture would not necessarily require a POP – mostly indicated for pain relief/mobility, can often be managed conservatively.

• An undisplaced spiral or oblique distal tibial fracture is characteristic
• These are often very difficult to see on initial x-ray. Sometimes theyre even invisible
• X-ray at 10 days often shows the healing fracture, soft tissue swelling and/or periosteal reaction. Management is then simple, with long leg POP for 2-3 weeks sufficient if required for pain control.
• These are a differential diagnosis to consider in the presentation of the limping child

Tillaux fracture

This is an uncommon fracture, unique to adolescents because the distal tibial physis fuses from the lateral to the medial side. Beyond 16 years, the physis is closed and these injuries are not seen.

It occurs in the ankle of the young person (between a narrow window of 14-16 years only) when a forced hyper-flexion and/or supination occurs at the ankle.

The fracture extends from the tibial diaphysis through the distal tibial physis anteriorly (SH II), but also medially out through the physis (SH II) and inferiorly through the epiphysis (SH III). This component is therefore intra-articular.

Caution is required with Tillaux fractures because the Ottawa ankle rules applied to these injuries can miss them. This is because it is not uncommon for the patient to be able to weight bear and the defined bony points are non-tender. The tenderness is usually elicited at the anterior ankle joint line which Ottawa does not describe.

Risk of Abuse

A high index of suspicion is needed to make a diagnosis concerning any form of abuse. The highest percentage of child abuse occurs between birth and 2 years of age [1].

Children most at risk of abuse include:

• Firstborns
• Unplanned births
• Premature children
• Stepchildren

Children with an increased risk of abuse include:

• Children in a single-parent home
• Children of parents who abuse alcohol or drugs
• Children of parents who were themselves abused
• Children of unemployed parents
• Children of families of lower economic status
• Children of parents who have a history of psychiatric illness

Children of all socioeconomic backgrounds can suffer physical abuse or neglect.

Signs of Abuse

Features to watch out for, that may raise concerns of abuse:

• An unusual or questionable history
• A changing history
• The finding of multiple skin bruises or burns
• Multiple Emergency Department attendance
• Late or delayed presentations to the ED

Knowledge of the injury patterns suggestive of NAI in children is essential. The most common locations (but least specific) for fractures due to child abuse are the humerus, tibia and femur [6].

The differential diagnosis in cases of suspected child abuse include true accidental injury, osteogenesis imperfecta and metabolic bone disease. Skeletal survey is a useful initial imaging modality but should be undertaken by the in-patient team after referral. The Emergency Department doctors job is to consider NAI. If concerned at all, refer the child on.

NAI consider it or miss it!

1. Jenabzadeh AR, Haddad FS. Principles of paediatric injuries. Br J Hosp Med (Lond). 2006 Nov;67(11):M202-3.
2. Currey JD, Butler G. The mechanical properties of bone tissue in children. J Bone Joint Surg Am. 1975 Sep;57(6):810-4. PMID: 1158919.
3. Salter RB, Harris WR. Injuries involving epiphyseal plates. J Bone Joint Surg Am; 1963; 45:587-622.
4. Landin LA. Fracture patterns in children. Analysis of 8,682 fractures with special reference to incidence, etiology and secular changes in a Swedish urban population 1950-1979. Acta Orthop Scand Suppl. 1983;202:1-109.
5. Libetta C, Burke D, Brennan P, Yassa J. Validation of the Ottawa ankle rules in children. Emergency Medicine Journal; 1999; 16(5)242-4.
6. Beaty JH. Orthopaedic aspects of child abuse. Curr Opin Pediatr 9; 1997; 1003.