In countries such as South Africa, trauma-related injuries are common occurrences. There are approximately 20 non-fatal incidents that result in disability for each violent fatality (Groenewald et al., 2008; South African Medical Research Council, 2008). Motor cycle, motor vehicle and pedestrian vehicle accidents, as well as assault, are listed as the main causes of injury in adults. Many of these patients are critically injured and require extensive treatment in an intensive care unit (ICU).

The American College of Surgeons’ national trauma data bank indicated that, in 2013, motor vehicle-related injuries accounted for 27% of cases in the data bank, especially in persons aged 19. Across the data bank, the leading two causes of death were fall-related injury followed by motor vehicle-related injury. Case fatality rates were reported to increase with the severity of injury sustained (National Trauma Data Bank Report, 2013). Multiple orthopaedic injuries account for approximately 10% of inpatient rehabilitation admissions in the USA (Uniform Data System for Medical Rehabilitation, 2004; Dubov et al., 2008).

High-energy injuries, such as road traffic accidents or a fall from a height, may result in traumatic brain injury or spinal cord injury together with pelvic, femoral shaft or tibial plateau fractures, as well as hip or knee dislocations in young adults. Elderly patients may sustain pelvic, femur or tibial plateau fractures from low energy injuries, such as a simple fall (Ip, 2008).

Common sites of injury in children with polytrauma are the head, chest, abdomen, genitourinary and musculoskeletal systems. Mortality in these children is usually associated with traumatic brain, abdominal or chest injuries (Kay and Skaggs, 2006; Abdelgawad and Kanlic, 2011).

The most common orthopaedic injuries in children with polytrauma are open fractures (about 10% of fractures in children with multiple injuries), compartment syndrome, pelvic injuries, multiple bone fracture, fracture-associated vascular injuries and spinal injuries (Abdelgawad and Kanlic, 2011). In the setting of high-energy or multiple traumas, children should always be assumed to have a spinal injury unless proven otherwise (Skaggs and Flynn, 2006). The presence of a pelvic fracture indicates that the child has been exposed to high-energy trauma and careful exclusion of other injuries is essential (Abdelgawad and Kanlic, 2011).

Most fractures are sustained during falls, motor vehicle accidents and other accidental injuries, including crush injuries (Rennie et al., 2007). However, non-accidental injury (NAI) should always be suspected in children presenting with multiple injuries, unless a clear and validated history to the contrary is obtained (Kemp et al., 2008; Abdelgawad and Kanlic, 2011). Warning signs of NAI include humeral fractures in children under three years and femur or tibia and fibula fractures in children less than 18 months of age (Pandya et al., 2009; Abdelgawad and Kanlic, 2011). Other fracture locations with a high specificity for NAI include the ribs, scapula, lateral end of the clavicle and vertebrae. In addition, the presence of fractures in different stages of healing, digital fractures in non-mobile children and bilateral fractures should raise a high index of suspicion for NAI (Jayakumar et al., 2010).

The mechanical properties of bone slowly degrade with age. There is net bone mass loss and increased brittleness with decreased ability to absorb energy, leading to an increased fracture risk. The most significant change in ageing bone is the ease with which a fracture progresses through the bone (Hipp and Hayes, 2009). Fragility fractures, such as neck of femur fractures, become more common as age progresses. Increasing age has been shown to play a role in the inhibition of fracture healing (Gaston and Simpson, 2007).

There are a number of differences between paediatric and adult bone structure that influence the injuries incurred during trauma. Children have a thicker periosteum, which commonly results in an intact periosteum on one side of the bone following a fracture, making closed reduction easier. The intact periosteum decreases the amount of fracture displacement, even in response to high-energy trauma. However, the limited bulk in children (fat and muscle mass) means that the bone is often more vulnerable to injury, as it is less protected than in adults (Musgrave and Mendelson, 2002). In children, a larger sub-periostial haematoma forms, which, together with the thicker periosteum, enhances the rapid formation of callus and hence bone healing (Gaston and Simpson, 2007).

Incidents such as a fall or direct blow to the elbow often result in a fracture of the radial head, the radial neck or both. Direct violence to the forearm, such as when warding off a blow during assault, results in shaft fractures of the radius or ulna. Commonly, fracture of one leads to dislocation of the other. A Monteggia fracture is a fracture of the ulna with dislocation of the radial head and is the most common fracture-dislocation injury in the forearm. Conversely, a Galeazzi fracture is a fracture of the radial shaft accompanied by a dislocation of the distal radio-ulna joint (McRae, 2006; Dandy and Edwards, 2009).

In the long term following complex pelvic fractures, patients may experience lingering pain, pelvic instability, leg length discrepancies, nerve and soft tissue damage and difficulty in sitting or, for females, giving birth (Adams and Hamblen, 2005; Hall and Brody, 2005).

Because the pelvis in children is more elastic than adults (requiring higher force to fracture), pelvic fractures in young children are rare (Musgrave and Mendelson, 2002). Most pelvic fractures that do occur in children are stable, with no widening of the symphysis pubis or sacroiliac joints (Abdelgawad and Kanlic, 2011). The vast majority of pelvic fractures in children can be managed without surgical intervention, but associated serious injury may cause significant morbidity and mortality, with the mortality rate for children with closed pelvic fractures being as high as 9% and up to 50% in children with ‘open book’ pelvic fractures (Musgrave and Mendelson, 2002; Skaggs and Flynn, 2006).

Hip dislocation may result from dashboard injuries during motor vehicle accidents, with energy transmitted up the femoral shaft into the hip joint. It may also occur with falls from a height or assault to the back of someone who is kneeling (McRae, 2006). Posterior dislocation of the hip (adduction and internal rotation abnormality) is most commonly seen with high-energy injury. Central hip dislocation may occur with acetabular fractures (Ip, 2008).

Anterior knee dislocation commonly occurs and is associated with significant knee ligament damage, vascular injury (especially the popliteal artery), common peroneal nerve palsy, displacement of menisci and fractures of the tibial spine (McRae, 2006; Ip, 2008).

Knee dislocations are rarely seen in children. They usually follow high-energy injuries and are more prevalent in older children and adolescents. There is a high risk of associated neurovascular injury, compartment syndrome and multiple ligamentous injury (Musgrave and Mendelson, 2002).

Any direct blow to the patella may result in joint cartilage damage, with or without fracture or dislocation. In the long term, patients may develop cartilage breakdown. Some may even develop erosion of the joint cartilage, with the associated development of degenerative joint disease.

Patellar sleeve injuries, characterised by avulsion of the patellar ligament from the distal pole of the patella, are unique to children and should be considered in any trauma patient who does not have full active knee extension (assuming the child is generally able to move actively) (Skaggs and Flynn, 2006; Staheli, 2006).

Ipsilateral fractures of the femur and tibia (combinations of diaphyseal, metaphyseal and intra-articular fractures) are called floating knee injuries. Floating knee injuries are generally the result of high-energy impact in the polytrauma patient. Concomitant knee ligament injury is often identified (Lundy and Johnson, 2001; Ip, 2008).

The tibial plateau is injured with violent blows (inwardly or outwardly) to the lateral side of the knee during weight bearing (also known as axial loading). This type of injury may occur as the result of a pedestrian vehicle or motor vehicle accident or with a fall from a height. Injuries that accompany tibial plateau fractures include meniscus, ligament and patella injuries (Ip, 2008).

Direct trauma to the lateral side of the lower leg can result in fracture of the fibula alone. Dislocation of the fibula head may lead to peroneal nerve injury (Wheeles, 2012). Direct trauma to the lower leg (e.g. fall from a height) may result in a fracture of the tibia alone. Open fractures are common with tibial fractures in which the subcutaneous section of the tibia is injured. The popliteal artery may be damaged with fractures of the upper tibia. Commonly, both the tibia and fibula are fractured with road traffic accidents (McRae, 2006; Dandy and Edwards, 2009).

Foot injuries account for up to 6% of all children’s fractures, with about half involving the metatarsal bones. Soft tissue injuries are relatively common, owing to the vulnerability of the paediatric foot (Musgrave and Mendelson, 2002).

In many hospitals a fracture is described by site of anatomical injury, e.g. undisplaced fractured head of humerus; however, various classification systems for fractures can be used in orthopaedic practice to describe injury severity and the need for surgical intervention. Some of the most commonly used classification systems in clinical practice are discussed in this section.

The most commonly used classification system is the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification of fractures of long bones. This complex system describes fractures of the humerus, radius and ulna, femur, tibia and fibula. Fracture types are described as least severe (Type A), intermediate (Type B) or most severe (Type C). This classification is used for each fracture that the patient suffers from. Comminuted fractures are generally described as Type B and complex fractures as Type C (McRae, 2006).

The Waddell-Fraser classification system is used to determine the severity of floating knee injuries. Two types of injuries are identified with subcategories (Ip, 2008):

The Schatzker classification is the most popular system used to describe tibial plateau fractures. Types IV–VI are related to high-energy impact injuries (Ip, 2008).

The aim is to achieve anatomic reduction of the physis without further injury that could affect growth.

Open fractures are graded according to the Gustilo-Anderson classification system, which takes into account the amount of energy, extent of soft tissue injury and contamination in order to grade fracture severity (Gustilo et al., 1984). This classification system is still widely utilised and is described below.

Avascular necrosis refers to the death of bone cells due to a lack of blood supply. This complication occurs more frequently in younger adults (aged 45 or less) and typically affects the femoral head, knee, talus, humeral head and scaphoid (Gao et al., 2013). Avascular necrosis results mostly from glucocorticoid therapy, alcohol abuse, long smoking history and blood clotting disorders.

Fat embolism syndrome develops when fat molecules accumulate in the lung parenchyma and peripheral circulation. The syndrome develops within 72 hours of fractures of the long bones and pelvis or major trauma. It is more frequent in closed than open fractures (Gupta and Reilly, 2007). Patients with fat embolism syndrome develop distinct changes related to the respiratory system, neurological changes and petechial skin rash. Respiratory system changes include dyspnoea, tachypnoea and hypoxaemia, and some patients may require mechanical ventilation (MV) (Gupta and Reilly, 2007). Neurological changes develop after the onset of respiratory distress and may range from mild confusion to severe seizures (Gupta and Reilly, 2007). Petechial rash typically develops in the conjunctiva, oral mucus membranes, neck, axilla and skin folds of the upper body (Gupta and Reilly, 2007).