Fractures and dislocations

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24.2 Fractures and dislocations

Robyn Brady, John Walsh

Essentials

1 Fractures are common in childhood, due to high-level motor activity, developing co-ordination, and the mechanical properties of the growing skeleton. However, compared to adult mechanisms, the majority are relatively low-force injuries.

2 The patterns of bony disruption are completely different from adult fracture patterns and include buckle and greenstick fractures and growth-plate injuries. Bony disruption/deformity is more common than ligamentous disruption: ‘sprains’ and ruptures are uncommon.

3 Displaced fractures are a common and highly traumatic event for children and rapid attention to physical and psychological distress can minimise the effects of this trauma.

4 Certain missed fractures have a high propensity for serious long-term functional morbidity and must be actively sought. These include elbow injuries, such as lateral condylar and Monteggia-type fractures.

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:

• infants/toddlers – higher proportions femur and skull fractures;

• primary school – higher proportion of elbow-region fractures, especially supracondylar;

• adolescents – complex ankle fractures; higher force sporting injuries; transition to adult pattern with increasing ligamentous injuries, e.g. elbow dislocations.

Fig. 24.2.1 Frequency of fracture types at Brisbane Mater Children’s Hospital ED.

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).

Fig. 24.2.2 Monteggia fracture-dislocation. Demonstration of the abnormal radio-capitellar relationship (see Fig. 24.2.8 for contrast).

Drawing by Terry McGuire.

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.

Fig. 24.2.3 Salter–Harris classification of epiphyseal fractures.

Drawing by Terry McGuire.

Fig. 24.2.4 Common distal radial epiphyseal fractures.

(A) Partial slipped distal radial epiphysis (Salter–Harris 1) with 10% translation; (B) slipped distal radial epiphysis (Salter–Harris 1) with 50% translation and probable intact dorsal periosteal sleeve; (C) Salter–Harris 2 fracture of distal radius with metaphyseal fragment angulated to 45 degrees and 50% translation of epiphyseal plate.

Drawing by Terry McGuire.

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.

Fig. 24.2.5 Tillaux fracture (Salter–Harris 3).

Early fusion of the medial distal tibial physis and relative superior strength of the distal tibiofibular ligament cause shearing force to separate the central physeal region and travel along the lateral distal tibial physis. Sometimes a metaphyseal fragment is also cleaved (Salter–Harris 4).

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.

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.

1. Rapport: establish rapport and explain procedures

2. Mechanism and associated dangers: rapidly ascertain mechanism and ensure primary survey stability and allergy potential

3. Pain management: where there is a greater than 90% likelihood of initial IV success, insert a small IV cannula into the opposite hand and titrate morphine 0.05 mg kg^–1 until pain relieved (appropriate monitoring should be in place). When no parent is present the risks of medication must be weighed against the potential benefit and attempts made to contact someone familiar with serious allergies or other medical problems. Other means of rapid pain relief include inhaled Penthrane or NO_2, and or intranasal fentanyl

4. Assess for site of anatomical disruption: look at and gently palpate the injured limb to estimate probable anatomical site of disruption, e.g. lateral elbow, mid-shaft forearm, etc. (comparison with other limb is often helpful)

5. Check for associated neurovascular dysfunction: (see Table 24.2.3), document and notify deficits immediately

6. Check for any evidence of an open wound: if this is present, cover with a sterile dressing and commence appropriate antibiotics IV, e.g. cefalothin 50 mg kg^–1 and notify orthopaedic team immediately

7. Immobilise limb: provide appropriate splintage (e.g. we use a POP slab for distal fractures, leaving radial artery palpable, and a fibreglass slab for elbow injuries, less radiological artefact-mouldable, re-usable, radiolucent slabs)

8. Keep stomach empty: identify time of last ingestion and inform patient and parent about fasting

9. Organise appropriate radiology

10. Discuss clinical and radiological findings with orthopaedic team

Table 24.2.3 Presence/absence of associated neurovascular injury
• Radial a: Pulse, cf. other side Hand perfusion/capillary refill, cf. other side • Brachial a: Beware spasm or intimal shear in supracondylar injuries • Radial n: Sensation dorsum hand, action = dorsiflex wrist, extend fingers (displaced humeral shaft injury) • Median n: Sensation thenar eminence, action = opposition, flexion IP thumb (supracondylar # or elbow dislocation) • Ulnar n: Sensation hypothenar eminence, action = abduction, adduction fingers (elbow dislocation, supracondylar #) • Posterior interosseous n: Branch of radial n, action = finger extension, e.g. (Monteggia #/dislocation)

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:

• to more clearly anticipate associated injuries (e.g. foreign bodies or distant possibility of abusive injury);

• to gather cumulative injury prevention data to support legislative change (e.g. road access); and

• to flag possible abusive injury, which is thought to have occurred in 1–2% of paediatric injury presentations, particularly in very young children.¹

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 • Proximal humeral or humeral shaft fractures under 3 years • Fractures with a shearing or distracting mechanism • Corner or ‘bucket-handle’ metaphyseal injuries • Femoral fractures in infants • Rib fractures • Complex skull fractures • Multiple fractures, especially different ages
Presentation features • Delayed presentation • Different care-giver • Unwitnessed injury • Recurrent fractures • Unexplained soft-tissue markings • Unexplained tension/anxiety
Assessment • Draw diagram of injury history as described by witness • Examine child all over and plot weight • Ascertain any previous history of burns or fractures • Is the developmental level compatible with the explanation? • Is the history adequate to explain the injury?
Rule of thumb • Infants within view, toddlers within earshot, unless asleep, i.e. injuries to pre-school children are usually seen or heard
Refer • All fractures in children under 12 months, and all fractures in children under 4 years in which there is an inadequate or questionable mechanism, should be discussed with a child-protection specialist. In the interim, supportive and non-judgemental care for child and care-giver must be maintained

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

Upper limb and shoulder girdle injuries

Midshaft clavicular fractures

These may occur at any age from a fall onto the shoulder or outstretched hand, are usually greenstick in nature and heal well in a sling or figure-of-eight bandaging. A fall onto the point of the shoulder, such as would cause an acromioclavicular disruption in an adult, may cause a lateral clavicular physeal fracture-separation. If these are posteriorly displaced, operative treatment may be required. Treatment is by sling or shoulder immobilisation followed by graduated exercises.

The neonatal shoulder may come to medical attention due to asymmetrical arm movement or swelling. Causes include birth injury with clavicular fracture or brachial plexus injury, proximal humeral physeal separation, and joint or bone infection. Senior orthopaedic involvement is essential for the diagnosis, and non-accidental injury must be considered. The prognosis for neonatal clavicular injuries is excellent.

Shoulder dislocation

This is uncommon under 10. The adolescent anterior dislocation can be reduced by traction in the prone position or by gentle arm traction to a seated child against counter-traction with a sheeted thorax.

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.