Fractures and dislocations of the upper limb in children

Introduction

It must be realised that children are not merely small adults, and this is particularly true with fractures and dislocation of the upper limb. Although superficially the injuries may appear to be the same, the pattern and prognosis of the injuries are often very different. Fractures of the proximal humerus in adults are a major problem; they are often complicated by nonunion, avascular necrosis and a poor functional outcome, and the patient may require joint replacement. In children the fracture usually represents an epiphyseal injury and the prognosis is very good, often without treatment, despite significant angulation at the fracture site. Shoulder dislocation, a common adult condition, is very uncommon in children. Apparent dislocations in children are often due to epiphyseal fractures and again may not require treatment. It is therefore necessary to be aware of the ossification centres of the upper limb when dealing with these injuries.

Ossification

A large part of the body of the scapula is ossified at birth. A secondary ossification centre appears in the coracoid during the first year and fuses by about the 15th year. The acromion usually develops two ossification centres, with all ossification centres fused by about the age of 20. These may be confused with fractures on radiographs or predispose to epiphyseal separation. Failure of fusion of the acromion resulting in an os acromiale occurs in about 5 per cent of the population, although there is a number of different reports of the incidence in the literature.

  The clavicle develops two ossification centres around the fifth to sixth week of foetal life. These fuse within a few weeks of their appearance; failure of this may produce a congenital pseudoarthrosis of the clavicle. A secondary ossification centre appears in the medial end of the clavicle in the late teens. An epiphyseal injury may occur before the appearance of this ossification centre giving the appearance of a sternoclavicular dislocation. This epiphysis fuses by about the age of 25. The lateral end occasionally develops a secondary ossification centre at the age of 18—20. This is usually small and rapidly fuses to the shaft.

The shaft of the humerus is evident at birth, with the head appearing by about 6 months. The greater and lesser tuberosities appear around the age of 2 and 5 years, and fuse by the age of about 6 to produce a conical growth plate. In children under the age of 6 fracture through this growth plate is usually a Salter and Harris type I injury, as before the tuberosities fuse the growth plate is more transverse. In the older child a Salter and Harris type II fracture occurs through the conical growth plate. The proximal growth plate accounts for 80 per cent of the humeral growth.

There are six ossification centres around the elbow and the usual order of appearance is shown below in Table 22.1, together with the approximate time of appearance. In general ossification centres appear earlier in females than males.

The shafts of both the radius and ulna are evident at birth.

General principles

With any childhood injury the possibility of child abuse must always be considered. In general this does not apply to injuries around the shoulder, as most of these injuries occur in those over 5 years old, an age at which child abuse resulting in fractures is uncommon. In the under 5 year old a proximal humerus fracture is rarely due to child abuse, although clavicle fractures especially in those under 18 months should be viewed with suspicion. Spiral fractures of the humerus in young children should also be considered as nonaccidental injuries, although distal humeral fractures and elbow fractures in general are usually not due to child abuse. If, however, the mechanism of injury does not fit the history given or there was a significant delay in presentation, then nonaccidental injury should be considered.

In a child of any age, an open fracture must be treated by operative debridement and stabilisation of the fracture site. In children, as in adults, polytrauma is a relative indication for surgical treatment.

Epidemiology

The risk of at least one fracture up to the age of 16 in a boy has been reported to be 42 per cent. In girls the quoted figure is 27 per cent. Of these, fractures of the distal forearm are the most common, accounting for about 20 per cent of the total. Fractures of the clavicle accounted for 8 per cent, the fourth most common site of fracture in children, with the midshaft of the forearm and the supracondylar region of the humerus both causing about 3 per cent of the fractures. The proximal humerus accounted for 2 per cent, and other fractures around the shoulder accounted for less than 1 per cent of all childhood fractures.