In this section
The history of the injury is often inadequately taken and documented. The history should include the mechanism of injury (e.g. fall on outstretched hand), velocity, direction of force and any unique features of the incident. The height of a fall or the nature of the collision during sport may give important information as to the type of severity of the injury.Fractures can be caused by indirect or direct forces:
There are four main situations in which the history can be anything but straightforward. These are non-accidental injury (NAI), occult injury, pathological fracture and stress fracture.
Gain the child's confidence by examining the uninjured side first, then move to the injured limb, remote from the site of pain, and then examine the part in question.Look for deformity, swelling, tenderness and breaks in the skin (Figure 22). Evaluate the neurovascular status.
Figure 22: Skin breach in an open supracondylar fracture. Notice the proximity of the median nerve and brachial artery to the fracture site.
The presence or absence of active movements can be helpful in infants. Those with a painful injury to the arm, for example, will often hold it so still compared with the normal side as to give the impression of paralysis. "Pseudoparalysis" in the leg is noted by the absence of normal kicking movements.The antalgic gaitChildren with a painful injury in the lower limb will automatically modify their walking to minimise pain. This varies from complete refusal to walk to walking with a characteristic limp, or "antalgic gait" (which means pain-avoidance gait). They spend less time on the sore leg, putting the foot down gently with the hip, knee, and ankle flexed to reduce impact and pain. The principal causes of antalgic gait in children are injury, infection (osteomyelitis or septic arthritis) and tumour.
Is there localised tenderness?Displaced fractures are easily recognised by localised swelling, bruising and deformity - it is not necessary to test for tenderness.Buckle injuries and undisplaced physeal injuries can be difficult to recognise visually. This is when the sign of local tenderness is very useful and often neglected. Radiographs will reveal the injury; however this presupposes that the likely site of injury can be precisely identified, otherwise the area of interest may not be included in the radiographs or the views are of such poor quality as to be non-diagnostic. Clinical examination, looking for local tenderness, should always precede radiology.Is there neurovascular compromise?Neurovascular injury is commonly seen in supracondylar fractures of the humerus and displaced fractures, or physeal injuries near the knee. The most common causes of compartment syndrome in children are forearm fractures and tibial fractures. Serial documentation of the peripheral pulses and compartment status from first arrival in ED is vital to deciding the urgency of management. Injured children can be uncooperative because of pain and anxiety. However, a basic motor examination can usually be conducted by showing the child the action, asking them to do the same movement first on the uninjured side, then on the injured side (Figure 23). Sensory examination (Figure 24) is more difficult. The absence of sweating in the hand and fingers follows sensory loss. After a supracondylar fracture, if the median and ulnar nerves are working, the fingers will feel moist because of increased sympathetic outflow secondary to pain and anxiety. By comparison, fingers with an impaired nerve supply feel distinctly dry.
Figure 24: Sensory nerve supply of the hand. Sensory examination is difficult. The absence of sweating indicates an impaired nerve supply.
Standard projections: Anteroposterior (AP) and lateral radiographs About 95% of fractures in children are diagnosed and managed with information from plain radiographs. Radiology comes after history and examination. Deciding on what radiology is needed is easy and logical after a history and examination. The area of localised tenderness is the best guide to the radiographic area of interest. In addition, it is important to consider x-raying the joints above and below. A fracture of the femur may occasionally be associated with a dislocation of the hip. A fracture of the ulna is often associated with a dislocation of the radial head (Monteggia fracture-dislocation). Analgesia and temporary (radiolucent) splinting is good for the child, the parent(s) and the radiographer. Requests to x-ray the whole limb are usually made as a substitute for history and examination. This exposes the child to unnecessary radiation and the resulting films are often not diagnostic. Non-standard projections In certain specific injuries oblique views are chosen to supplement the standard AP and lateral views. These are particularly helpful in three settings:
It is helpful to use standard terminology to describe what has been seen on x-ray for the purposes of documentation and especially for communication if a child requires referral to another department or to another facility. This is summarised in Table 3.
Figure 25: A) Measuring angulation in a distal radial fracture B) Measuring angulation and displacement in a femoral shaft fracture.
Table 3: Steps in describing a fracture on x-ray
The cartilaginous parts of epiphyses are not calcified and are not visualised on plain films. The cartilaginous epiphysis can be outlined with injected contrast material when more detailed information is required (Figure 27). It is sometimes apparent that a child has a displaced fracture or epiphyseal injury to the distal humerus, although the precise anatomical diagnosis cannot be made with certainty on a plain film. If the child requires a general anaesthetic for reduction or fixation, a contrast arthrogram can be performed, as a preliminary procedure. The alternative is an MRI scan, which is also very effective in visualising soft tissues, including cartilage. MRI in younger children usually requires anaesthesia.
This technique utilises a bone-seeking isotope such as technetium-99m phosphate, which identifies areas of bone with increased blood flow. It has the advantage of delivering a low radiation dose and is highly sensitive but not specific. Fractures, infections and tumours may all be "hot" on a bone scan. Bone scans can pinpoint the site of an occult (stress) facture in the proximal tibia or a toddler's fracture, which cannot always be seen radiographically. In the child with multiple injuries, the technique is a very sensitive means of revealing the presence of occult injuries. Bone scans are superior to plain x-rays to detect rib fractures at the costovertebral junction, undisplaced fractures and subperiosteal haemorrhages in NAI.
CT provides three dimensional imaging. It is the preferred method of assessing head injuries, fractures of the spine and pelvis and in areas where plain x-rays tend not to provide adequate definition (Figure 28). CT exposes the child to more radiation than plain films or a bone scan. It should only be requested when the risk justifies the anticipated benefits. Most children do not require a general anaesthetic for a CT examination because scan times are relatively brief. Severely injured children require full clinical assessment, resuscitation, analgesia and stabilisation prior to scanning.
MRI is a highly sensitive technique that provides detailed three dimensional imaging of both bone and soft tissues. It is therefore the definitive tool to assess the degree of injury to the brain and spinal cord after major trauma. The example that illustrates its unique value is that of spinal cord injury without radiological abnormality (SCIWORA). MRI is useful in distinguishing between stress fracture, osteomyelitis and bone tumour. The major advantages of MRI over CT are the ability to image soft tissues and the absence of ionising radiation. The major disadvantage of MRI in the acute setting is the scanning time and the need for anaesthesia in the majority of children.
Radiological appearance of callus formation, which is evidence that a fracture is healing, is seen in children from seven to 14 days after injury (Figure 33). This depends on the age of the child and nature of the injury. The younger the child, the earlier will callus be seen.
Clinical union is said to be present when the bone is no longer painful and does not deform under load. Radiological union, on the other hand, describes the healing process rather than a time point or event. Hence definitions of delayed union or non-union tend to be rather arbitrary. They are usually defined in relation to the "average time" to union for the particular fracture in question, given the child's age. These complications are rare in childhood.