Introduction

Since radial head fractures are very rare in children ¹ this chapter will concentrate on paediatric fractures of the radial neck and their management.

Radial neck fractures account for 1% of all fractures and 5–14% of elbow fractures. They involve all age groups from childhood to prepuberty, with a peak incidence at around 9–10 years of age. They occur at a younger age in girls than in boys (approximately 2 years earlier).²

Most often the injury is a Salter–Harris type II, or complete fracture of the neck itself. Some of these fractures are very difficult to treat, with many possible complications, all of which have a significant, deleterious effect on joint function. The degree of initial anatomical disruption, especially if associated with a vascular lesion, has a major effect on outcome. However, the inadequacies of difficult primary treatment are equally responsible. Open reduction with a condyloradial Steinmann pin is usually associated with a high incidence of complications and, whenever possible, closed treatments are preferred by most paediatric orthopaedic surgeons. To avoid open reduction, two closed methods are helpful and will be described: intramedullary pinning as proposed by JP Métaizeau et al,³^–⁸ and percutaneous pinning.⁹^–¹¹ In our experience, open reduction only becomes necessary when the above methods cannot obtain reduction. Even in these circumstances, osteosynthesis may require intramedullary pinning.

Clinical Pearl 11.1

Percutaneous pinning or intramedullary pinning is the preferred treatment options for displaced radial neck fractures. Open reduction should be avoided if at all possible.

Aetiology

The mechanism of injury is usually an indirect force. It results from a fall onto the outstretched hand in which the elbow is extended or slightly flexed and a valgus force is applied to the elbow joint. According to the Jeffery classification, which is based on the mechanism of injury, it is a type I injury.¹² The head of the radius is driven against the capitulum. As the radial head is essentially cartilaginous, it is more resistant to trauma, which is why isolated radial head fractures and epiphyseal separations are so rare. Typically, the proximal radial metaphysis cannot withstand the sudden axial compression forces to which it is subjected, and breaks. Radial neck fractures may also occur in association with dislocation of the elbow: Jeffery type II injury.¹³ If this occurs during a posterior dislocation of the elbow the radial head remains in an anterior position.¹⁴ If, however, it occurs during reduction of the dislocation the radial head will remain posteriorly dislocated (posterior to the capitulum). This form of fracture adversely affects the prognosis because there is an associated vascular risk and because reduction of the fracture is significantly more challenging.

Clinical Pearl 11.2

An 8-year-old child fell on their elbow. Initial X-rays, and more particularly the lateral view, showed a Jeffery type II radial head fracture (A, B). It was treated by closed reduction and FIN. On the fluoroscopic image, note the 180° rotation of the radial head (C). Open surgery was necessary to perform reduction and FIN (again) using a 1.5 mm nail (D, E) The implant was removed in the 4th postoperative month. At 10-month follow-up function was excellent with full range of motion, but the X-ray showed significant remodelling of the radial head (F). Still, viability of the epiphysis was confirmed by MRI.

Note: this unusual fracture needs to be better known.

Other forms of radial neck fracture can also occur. The most common by far is the pure metaphyseal fracture of the radial neck with subsequent Salter II epiphyseal separation. The other types of epiphyseal separation, particularly those with intra-articular fracture extension (Salter types III and IV), are exceptional.

Associated injuries are frequent, from fracture of the olecranon that occurs in an extended elbow, to dislocation of the elbow joint with or without avulsion of the medial epicondyle in an elbow that is slightly flexed on impact.^15,¹⁶ Skin lesions and neurovascular injuries are, however, rare.

During displacement, a metaphyseal periosteal flap often remains attached to the radial head. Preservation of this sleeve, which contributes to the vascular supply of the radial head, is critically important for two reasons: first, to preserve the blood vessels it contains; and second, because once tensioned this piece of tissue will assist in maintaining the reduction.

Presentation, investigation and treatment options

The child usually presents having fallen onto the outstretched hand. The injury most frequently occurs during sport, play or after a simple fall. Clinical examination reveals a swollen elbow that must be carefully evaluated. In addition to assessing the bony anatomy of the joint it is also essential to examine the neurovascular status of the forearm and hand. Anteroposterior (AP) and lateral radiographs of the elbow should routinely be undertaken, the fracture configuration studied and displacement of the radial head measured. Accurate classification of the injury enables appropriate treatment to be instituted. Although many radial neck fracture classifications have been developed,^1,^12,¹⁷ that described by Métaizeau et al⁴ is perhaps the most useful. This classifies radial neck fractures based on translation and is useful because of its influence on prognosis (Table 11.1):⁴

• Grade 1: a simple shift with the epiphysis remaining horizontal

• Grade 2: the epiphysis is tilted so that its articular surface forms a <30° angle with the horizontal

• Grade 3: the tilt is between 30° and 60°

• Grade 4 is divided into two groups:

– Grade 4a: tilting does not exceed 80°

– Grade 4b: tilting is between 80° and 90°.

Table 11.1 Judet classification with Métaizeau modification

In 30–50% of severe displaced radial neck fractures another fracture of the elbow joint will have occurred. Most often there is a fracture of the olecranon, lateral condyle, medial epicondyle or ulna, all of which may require an additional procedure with appropriate osteosynthesis.¹⁶

Preoperative complications of radial neck fractures are seldom seen but occasionally protrusion of the fractured end of the bone through the skin may occur in association with a fracture of the olecranon. Vascular lesions are hardly ever seen. A careful assessment of the radial nerve is essential at the time of presentation because of its close proximity to the fracture. It should also be re-examined after any intervention, particularly if a punch is used to achieve fracture reduction.

Early postoperative complications are those of any surgically treated fracture and include compartment syndrome, early infection and redisplacement of the fracture.

Clinical Pearl 11.3

30–50% of severe displaced radial neck fractures are associated with another fracture of the elbow joint.

Surgical techniques and rehabilitation

Conservative treatment

In grade 1 an above-elbow cast for 4 weeks, with the forearm in pronation, will give excellent results.

In grades 2 and 3 reduction of the fracture is required. Under neuroleptanalgesia, the forearm is gently moved in partial extension–adduction to create a space into which the displaced radial head is reduced. The forearm is rotated to place the radial head in a position from which it may be pushed into the correct alignment by direct pressure from the surgeon’s thumb. The forearm is then gently turned in pronation, as this tightens the annular ligament, maintaining the head above the metaphysis. The stability of the reduction is maintained by slight pronation of the forearm, and immobilization in an above-elbow cast for 6 weeks.

A question that is frequently asked is: allowing for the remodelling capacity of the proximal radial epiphysis, what amount of residual tilting can be accepted in order to permit good results? According to the literature, a residual displacement of 30°, and sometimes 50°,¹⁸ is well tolerated and can correct itself spontaneously. This value must be correlated to the age of the child, since a minimum of 3–4 years of growth is required to achieve adequate remodelling. A tilt of 30° is therefore often acceptable in children.

Clinical Pearl 11.4

A residual radial head tilt of 30° will normally be remodelled, provided the child has 3–4 years of further growth.

Surgical treatment

Percutaneous pinning

A small stab wound is made on the lateral side of the elbow, 2–5 cm below the level of the radial fracture, depending on the amount of displacement. The more displaced the fracture, the lower the entrance of the wire. This approach must be posterior to the extensor radial muscles and with the forearm in pronation so that the deep branch of the radial nerve is protected by being displaced anteriorly. A smooth 2 or 2.5 mm K-wire is inserted through the wound, the subcutaneous tissues and the muscles to reach the radial head and neck (Fig. 11.1).

Figure 11.1 Use of a punch: the forearm is pronated to allow forward shift of the radial nerve and thus protect it from injury. The punch is placed on the epiphysis, not on the radial neck, in order to avoid potential damage to the precarious vascularization.

The radial head is then gradually pushed back into place. To avoid injury to the growth plate, the head itself must be pushed, or in some circumstances the wire should be introduced into the fracture to help the reduction. As these fractures are impacted, reduction can be difficult to obtain and the same wire may need to be redirected through the same stab wound several times before an appropriate reduction is achieved. This should then be verified by standard radiographs.

Although Lenggenhager originally left the pin in place in the cast, it is nowadays considered unnecessary as sufficient stability can be obtained with a long-arm cast with the elbow flexed at 90° and the forearm in neutral rotation for 3–6 weeks.¹⁹ The period of immobilization is determined by the age of the child and is shorter for younger children, whose fractures heal more rapidly.⁹

Clinical Pearl 11.5

Percutaneous pinning involves the use of a 2 or 2.5 mm K-wire and begins 2–5 cm below the level of the radial fracture.

Elastic stable intramedullary nailing (ESIN) technique

Published by Métaizeau et al in 1980,³ this method is very simple but requires perfect knowledge of the elastic stable intramedullary nailing technique, which is used in fractures of the forearm.²⁰