14.4 Injuries around the shoulder in children

Children cannot be considered as small adults, and this is especially true when dealing with injuries around the shoulder. Although one of the most common fractures in both is the clavicle fracture, this is where the similarity ends. Physeal involvement is a factor and the potential for remodelling is considerable. In particular, the pattern and behaviour of fractures of the proximal humerus in children is completely different from that in adults. Shoulder dislocation, a common adult condition, is very uncommon in children. Often epiphyseal fractures in children may appear as joint dislocations.

The three bones of the shoulder girdle—the clavicle, scapula, and humerus—connect with the torso via the sternoclavicular joint. The flat, triangular scapula provides attachment for 17 muscles, and expands into the acromion, which articulates with the clavicle, the coracoid, and the glenoid, which articulates with the humerus. The adult proximal humerus is considered in four parts: the articular head, the greater and lesser tuberosities, and the proximal shaft. In children, the most commonly injured site is the growth plate, and a fracture in the child rarely consists of more than two parts (Figure 14.4.1). In adults, the bony architecture cannot be considered in isolation from the soft tissues, especially the rotator cuff. In children, the growth plates and epiphyses must also be considered, and the rotator cuff is of less importance.

The scapula, formed by membranous ossification, is largely present at birth. The coracoid ossifies from two separate centres, fusing by the fifteenth year. By puberty, between two and five ossification centres form the acromion (Figure 14.4.2), which fuses by 20–22 years. Failure of acromial fusion, resulting in an os acromiale, occurs in about 5% of the population, visible on axial view. It may be confused with fracture.

The clavicle develops two ossification centres around weeks 5–6 of fetal life. These fuse within a few weeks of their appearance; failure of this may produce a congenital pseudarthrosis of the clavicle. A secondary ossification centre appears in the medial end of the clavicle in the late teens and fuses by about the age of 25 years. The lateral end occasionally develops a secondary ossification centre at the age of 18–20 years. This is usually small and rapidly fuses to the shaft.

The shaft of the humerus is evident at birth, with the head appearing at 6 months. The greater and lesser tuberosities appear between 2–5 years, fusing by 6 years to produce a conical growth plate with a posteromedial apex, which accounts for 80% of the humeral growth. In children under 6 years, fracture through this growth plate is usually a Salter–Harris type I injury, as before the tuberosities fuse the growth plate is more transverse. In the older child, a Salter–Harris type II fracture occurs through the conical growth plate, retaining the posteromedial metaphysic.

Falls, traffic accidents, and sports are the commonest cause of shoulder girdle injury. However, with any childhood injury the possibility of child abuse must always be considered. In general, most shoulder injuries occur in children over 5 years old, an age at which child abuse resulting in fractures is uncommon. In the under 5s a proximal humerus fracture is rarely due to child abuse, although all scapular fractures and clavicle fractures in those under 18 months old should be viewed with suspicion. Many of the other fractures seen around the shoulder occur after major trauma, and an appropriate history is available. However, if the mechanism of injury does not fit the history given or there was a significant delay in presentation, child abuse should be considered.

Children under 5 years have tremendous potential to remodel, and significant deformity can be accepted, especially in the proximal humerus. Given the malalignment and shortening that can be accepted even in adults, few of these fractures in children will need operative intervention.

Adolescents should be considered as adults if they are reaching skeletal maturity. The management of their injuries, including the indications for operative treatment, should be the same as those in an adult. In a child of any age, an open fracture must be treated by operative debridement, and stabilization of the fracture site. In children as in adults, polytrauma is a relative indication for surgical treatment.

High-energy trauma around the shoulder is very uncommon in children, so that examples of injuries such as scapulothoracic dissociation, or intrathoracic dislocations in children exist only as isolated case reports in the literature. They will not be considered further in this chapter.

The risk of at least one fracture up to the age of 16 years in a boy is 42%, and 27% in girls. Of these fractures, the clavicle is involved in 8–15.5%, the fourth most common site of fracture in children. Fractures of the proximal humerus account for less than 5%, the fourth most frequent epiphyseal injury. Other fractures around the shoulder account for less than 1% of all childhood fractures.

Infants of 4kg or more are at increased risk of fracture during birth. Ninety-five per cent% of birth fractures involve the clavicle by pressure from the symphysis pubis on the anterior shoulder in a cephalic presentation, and heal rapidly. Salter–Harris type I affect the proximal humerus if the arm becomes hyperextended or rotated during delivery.

Dislocations of this joint are rare in children and most apparent dislocations, even in adults up to the age of 25 years, represent epiphyseal separations. True dislocations and epiphyseal injuries can be manipulated closed and are often stable. Even if unstable, metalwork is avoided as disastrous results have been reported, including pin migration and infection. Sutures or repair of the periosteal sleeve are sufficient, with 3–4 weeks of sling immobilization as rapid healing and remodelling will occur. Anterior displacement is more common, whilst posterior displacement may be a surgical emergency if vital structures are compromised.

Fractures of the medial end of the clavicle were considered earlier.

Midshaft fractures account for 88% of children’s clavicle injuries (Figure 14.4.3), with a mean age of 8 years. The mechanism is a fall directly on to the shoulder with the arm at the side. A direct blow or a fall on the outstretched hand can rarely produce this injury. Greenstick fractures commonly occur, requiring temporary rest in a sling for a short period. Displaced clavicle fractures are very common, but rarely require reduction (Figure 14.4.1). A broad arm sling for 2–3 weeks until comfortable is all that is required. Malunion is very common but rarely causes a functional problem; non-union is very rare in children. Parents should be reassured that the prominent callus will usually resolve over the subsequent months; pressure to remove this ‘unsightly’ lump surgically should be strongly resisted.

Open reduction and fixation with wires or a plate may be occasionally required. The indications are similar to those in the adult: open fracture, skin compromise, vascular injury, etc.

Fractures of the lateral end of the clavicle may also be confused with joint dislocations, as discussed later.

True dislocations of this joint are unusual in children, especially in the younger child. The ligaments around the joint are very strong, and more often the lateral end of the clavicle will fracture, herniating through the thick periosteal sleeve although this may not be apparent on radiographs if it is unossified. The inferior periosteum is left behind, with the conoid and trapezoid components of the coracoclavicular ligament intact, producing a ‘pseudo-dislocation’. This will heal and remodel with conservative treatment, a sling for comfort followed by early mobilization. Rockwood et al. (1984) have classified these injuries.

Fractures of the coracoid are usually an epiphyseal separation. In combination with a lateral clavicle fracture, this constitutes a childhood equivalent of an acromioclavicular dislocation and represents failure through the epiphyseal plate before ligamentous injury.

Acromion fractures are rare in children and are often due to direct violence. An os acromiale may be confused with a fracture. Treatment depends on displacement, and other injuries around the shoulder. Wires, screws, tension band wiring, and plate fixation have all been used and non-union has not been reported in children.

These are uncommon injuries and usually represent direct violence. The significance of this injury is the possibility of underlying chest wall and pulmonary contusion rather than the scapula fracture itself. These injuries will almost always be treated conservatively with analgesia, and a sling for comfort. The arm should be mobilized as comfort allows.

Glenoid fractures are rare and represent a fracture dislocation of the shoulder. The size and displacement of the fragment must be assessed, and this is best achieved by computed tomography. Minimally displaced fractures respond to sling immobilization, rarely for more than 3 weeks. Indications for internal fixation, usually by a lag screw technique, include large displaced fragments, and an unstable shoulder. Operative approach, method of fixation, and postoperative mobilization will be determined by the fracture pattern and fixation achieved at surgery.

Shoulder dislocation in pre-teen children is unusual, as the ligaments are stronger than the epiphysis; more commonly a Salter–Harris fracture of the proximal humerus will occur. In adolescents as in adults, glenohumeral dislocation is frequently due to a sporting injury. Treatment is along adult lines, with early closed reduction using standard techniques. The recurrence rate is age related, highest in 14–17-year-olds, with a recurrent dislocation rate of 92%, in comparison with 33% for those under 12 years. When traumatic dislocations occur, Bankart lesions are found in 80%, leading to suggestions of prophylactic stabilizing surgery. This is controversial, but if recurrence does happen, surgery is indicated. Surgical patients are less likely to have recurrent instability, but in a study of 66 adolescents, stability improved anyway over 2 years with 90% performing at the same or higher levels of sport and work in both operative and non-operative groups. Another study has found no significant difference was found in functional outcomes between patients who had undergone surgical stabilization and those treated non-operatively.

Atraumatic dislocations can occur in children with joint laxity or connective tissue disorders and can be produced by voluntary muscle activity. Posterior glenohumeral dislocations in children have been reported as case reports.

Most fractures of the proximal humerus usually occur in the older child or adolescent. Not only are accidents more common at this age, but the perichondral ring may be weaker just before skeletal maturity. The majority of injuries occur through the growth plate; Salter–Harris type II in the older child, and type I in the younger child. Salter–Harris types III and IV are very uncommon injuries of the proximal humerus. No cases were reported in three of the largest series, which in total comprised over 200 patients.

Neer and Horowitz (1965) graded fracture displacement into four groups: group I, less than 3mm; group II, up to 33% of the shaft diameter; group III, up to 67% of the shaft; group IV, more than 67% displacement of the shaft. No specific grading of angulation was made, though noted to be always present in groups III and IV. Varus displacement is most common and is due to the pull of the pectoralis major attaching to the distal fragment which tends to pull it anteriorly and medially. Neer and Horowitz noted residual shortening in nearly 10% of patients of groups I and II at an average follow-up of 4.8 years. This figure rose to 33% of those in group IV, all treated by reduction, nine by open reduction and nine by closed reduction. Despite this, all patients had satisfactory functional results.

Baxter and Wiley (1986) in a review of the treatment of 57 patients, reported that manipulation of a displaced fresh fracture did not improve the final outcome, when humeral growth or function were assessed. Ninety per cent of the 30 patients they assessed more than 2 years after injury had measurable shortening; however, the maximum was 2cm, and none of their patients were aware of the shortening.

Conservative treatment is generally acceptable, not only because of the remodelling potential but also because some degree of malalignment can be accepted around the shoulder. An angulation of 45 degrees and 50% of displacement can be accepted (Figure 14.4.4). In the younger child, 70% angulation and any bony contact should heal with good functional results. The fracture is usually treated in a collar and cuff sling, although rarely a hanging cast may be used in the older child with significant shortening or angulation.

If the position is unacceptable, closed reduction is attempted and the fracture held with two or three wires (Figure 14.4.5). These wires can be removed after 3 weeks. The use of cannulated screws instead of wires allows earlier and unimpaired mobilization. Premature closure of the growth plate will occur, but this method of treatment will usually be used in the adolescent approaching skeletal maturity Figure 14.4.6).

Open reduction may occasionally be required for soft tissue interposition often the biceps tendon, and this can be achieved through a standard deltopectoral approach (Figure 14.4.7). Fracture stabilization is carried out as described earlier.

This may occur with direct trauma, or may occur as a pathological fracture, classically through a unicameral bone cyst (Figure 14.4.8). Displacement is not usually significant; angulation may occur but rarely produces a functional problem. The fractures usually heal rapidly with conservative treatment in a sling. The proximal humerus is the only common site for pathologic fractures around the shoulder.

Fractures of the clavicle or proximal humerus are relatively common injuries in childhood; most can be treated conservatively with excellent functional recovery.

Other fractures are uncommon and an awareness of the basic ossification patterns will further inform a radiographic abnormality. Joint dislocations are very rare in a child; injury usually occurs through an epiphysis near to the joint. Again, a good result can be expected with conservative treatment.

High-energy shoulder trauma or polytrauma need to be treated on an individual basis, following the basic principles of trauma care.