Fractures and dislocations

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24.2 Fractures and dislocations

Fracture patterns in childhood

In the previous chapter the impact of development (behavioural and physiological) on musculoskeletal pathology was broadly outlined (see Table 24.1.1). With respect to injury, this means different points of cleavage or deformation from a given injury mechanism, and an extra anatomical structure (the physis) to consider when analysing the effects of trauma and the future outcome of a given disruption.

Fig. 24.2.1 shows the frequency of common fractures presenting to a children’s emergency department (ED). Within different age subgroups, the distribution varies thus:

The majority of ED paediatric fracture presentations occur at the distal radius and ulna. This is one of the top ten ED diagnoses for children in Australia. Many displaced forearm fractures can be reduced under sedation by emergency staff with appropriate training and follow-up, making this a most valuable area of expertise.

Paediatric limb fractures, depending on the angle of force to which they have been subjected, can occur to shaft, metaphysis, or physeal region. The different quality of developing bone means that even injuries to shaft and metaphysis tend to have different patterns of deformation, including ‘torus’ or buckle injuries, bowing, and greenstick fractures. The importance of this awareness for the emergency physician is best illustrated by the Monteggia equivalent injury in which ‘shortening’ from proximal radial dislocation is ‘matched’ by ulnar bowing. The resultant injury has no radiologically obvious ‘fracture’ in the traditional sense but has serious consequences if not recognised and reduced (Fig. 24.2.2).

The Salter–Harris classification (Fig. 24.2.3) remains the most useful way of describing the pattern of cleavage with respect to the physis. In reality, types 1 and 5 represent mechanical force patterns (separation and compression) rather than a radiological pattern as, unless there is lateral translation or adjacent bony or soft-tissue deformation, the physis may appear radiologically normal in these injuries. An example of Salter–Harris type 1 injuries with lateral shift is the so-called ‘slipped distal radial epiphysis’ (Fig. 24.2.4). The disorder of slipped upper femoral epiphysis (SUFE) has been discussed in Chapter 24.1 as, although minor trauma may precipitate an acute slippage, the cleavage is due to an abnormal physeal predisposition and should not be looked upon as truly traumatic.

Salter–Harris type 2 injuries are the most common physeal injury pattern seen, the metaphyseal corner (the ‘Thurston-Holland’ fragment) ranging in size from a barely visible fragment to an extensive triangle. Injuries through the epiphysis itself, Salter–Harris types 3 and 4, are more worrying in their prognosis because they are intra-articular as well as involving the physis. The classic example of a Salter–Harris type 3 injury is the Tillaux fracture (Fig. 24.2.5), while lateral condylar fractures at the elbow are Salter–Harris 4 in type.

Table 24.2.1 shows some examples of the corresponding injury occurring in adults and children for a given mechanism. This table illustrates the maxim that children tend to fracture rather than ‘sprain’, as the physis is the weakest point of the musculoskeletal continuum, i.e. a ligament will avulse its bony origin or insertion rather than tearing. In some cases, this is to the child’s advantage, as the cellular architects of bone development which contribute to its mechanical weakness contribute to rapid healing and extensive remodelling. A midshaft femoral fracture, for example, will heal in 2–3 weeks in an infant, whereas the same disruption will take 12 weeks to union in a teenager.

Table 24.2.1 Examples of paediatric vs. adult outcomes of common fall mechanisms (different paediatric injuries occur at different ages depending on planes of weakness). The ligaments in children provide greater resistance to shear injury than the growing bone, so avulsion type injuries occur in place of ligamentous tears or dislocations.

Mechanism Adult injury Paediatric injury Fall onto point of shoulder AC separation Lateral clavicular fracture Shoulder extension/compression Shoulder dislocation Proximal humeral fracture Fall on hand, elbow hyperextension Elbow dislocation Supracondylar/condylar fractures Wrist hyperextension/compression Scaphoid fracture Distal forearm fracture Fall onto hand Colles’ fracture Midshaft, metaphyseal, or epiphyseal fracture Thumb abduction 1 Bennet’s fracture Metaphyseal fracture base first metacarpal Thumb abduction 2 Gamekeeper’s thumb (UCL) UCL avulsion fracture (Salter–Harris type 3 proximal phalanx thumb) Rotation of knee on lower leg ACL, cartilage tear Tibial spine fracture Valgus/varus knee stress Ligament, cartilage tear Distal femoral physeal separation Forceful jump (quadriceps) Ligament tear Patellar tendon avulsion fracture (Tibial tubercle) fracture Forceful jump (calf) Achilles tendon tear Calcaneal avulsion fracture Rotation of tibia on calcaneus Ankle sprains, Pott’s fractures Tibial spiral fracture, Tillaux fracture, triplane fracture Inversion ankle Talofibular ligament tear Salter–Harris type 1 or 2 distal fibula

Initial assessment and management

The initial assessment of the paediatric isolated limb injury (fracture/dislocation) is shown in Table 24.2.2 and the neurovascular assessment in Table 24.2.3. Limb injury must always be considered in the broader context of trauma. Primary and secondary survey, however brief and targeted, should always be carried out bearing in mind the described injury mechanism and the child’s complaints of pain, so that any associated injuries, e.g. to head, abdomen, or spine, may be recognised and evaluated early. An efficient early assessment should be able to establish mechanism, possible other sites of injury, probable fracture type, presence or absence of compound features or neurovascular impairment, and organise pain relief, fasting, radiology, splintage, and antibiotics if required, within a brief period.

Table 24.2.2 Initial assessment and management of traumatic limb deformity

Table 24.2.3 Presence/absence of associated neurovascular injury

Fracture descriptions to the orthopaedic team should start with the child’s age, mechanism, and clinical findings, and proceed to the part of bone, type of fracture, and extent of angulation and/or displacement and associated findings. Clinical findings must always be kept paramount. Skin breach must be actively sought and described, then photographed and covered with a sterile dressing. Prominently placed photographic displays of common paediatric fractures within the emergency department may aid accurate description.

Doctors share in the community responsibility for child safety. Within the ED setting this means getting a clear description of the setting and mechanism of injury, particularly with injuries to pre-verbal children. These data are important:

In general, fractures in pre-verbal children without a clear, developmentally appropriate mechanism/history or with other concerning features, will need further assessment. Features suggestive of non-accidental injury are shown in Table 24.2.4, and child abuse is discussed in more detail in Chapter 18.2. As a minimum, all fractures occurring in children under 12 months should be discussed with a paediatrician or child-protection specialist.

Table 24.2.4 Features suggestive of possible non-accidental injury
Fractures

Presentation features

Assessment

Rule of thumb

Refer

The following sections describe the mechanism, recognition, and ED treatment of individual fractures.

Upper limb and shoulder girdle injuries

Proximal humerus

These fractures vary from minor buckling at the proximal metaphysis, to proximal humeral epiphyseal Salter–Harris type 2 fracture-separations (Fig. 24.2.6). Because of the universal motion at the glenohumeral joint and the remodelling potential of children, a remarkable range of initial traumatic deformity is acceptable in children prior to physeal closure (age 14–16), including complete displacement and up to 60 degrees of angulation.2 A collar and cuff is the usual treatment.

Injuries to the elbow region

The elbow region accounts for 10% of all paediatric fractures. Supracondylar fractures make up 75% of these, and lateral condylar fractures 17%.3 Missed or inadequately treated paediatric elbow injuries figure prominently in orthopaedic litigation series.4

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