Introduction

Since radial head fractures are very rare in children¹ 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.

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

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.

Surgical techniques and rehabilitation

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

Surgical preparation

As is often the case in trauma surgery, retrograde ESIN is preferably performed under general anaesthesia instead of regional block anaesthesia in order to facilitate postoperative monitoring. Furthermore, reduction is best achieved with the patient under general anaesthesia as it permits complete relaxation of the muscles.

The child is positioned supine on the operating table with the injured upper limb on an attached radiolucent arm table. A tourniquet is placed around the upper arm. It is not systematically inflated but it may prove useful should open reduction be required.

An image intensifier is usually placed parallel to the operating table and perpendicular to the arm table, at the level of the child’s axilla. In this position, the surgeon can face the image intensifier and the posterolateral compartment of the elbow, and has a straight-shot access to the radial head and easy access to the distal radial metaphysis. Reduction is performed under fluoroscopic guidance. For the AP projection the elbow is extended in a mid-pronation position. For the lateral projection it is flexed 90° in a mid-pronation position, and the shoulder is positioned in full external rotation.

The entire upper limb is prepped. A sterile upper extremity drape is used which extends down to the tourniquet, and covers the child’s body including the trunk and the lower limbs.

Closed reduction

A closed reduction is attempted. The ESIN technique is used either to stabilize the reduced fracture or (and this is the most common) to reduce and stabilize the radial neck.

Two different reduction manoeuvres can be used but, prior to anything else, the surgeon must determine the plane of maximal displacement of the radial head. This is achieved using image intensification at progressively larger angles, from supination to full pronation. The plane of maximal displacement is found when the radial head forms an almost perfect rectangle, with a clearly and entirely visible physis. It is generally translated in the posterolateral direction, so that the plane of maximal displacement is best visualized in 20° to 40° of pronation (with reference to a full supination position).

The first reduction manoeuvre involves the assistant placing a varus stress on the extended elbow and applying traction to restore the joint space, while the surgeon places his/her thumb on the assumed position of the radial head (i.e. in the plane of maximal displacement) and gives a firm push in an upward and medial direction to return the radial head to its normal position. In this method the forearm is supinated, but many variants have been described. According to other authors, the elbow should be slightly flexed for better muscle relaxation. Jeffery recommends a small amount of pronation of the forearm to ensure that the push is applied in the plane of maximal displacement.

An alternative reduction manoeuvre involves replacing the thumb with a punch as described above.

Clinical Pearl 11.6

Before attempting ESIN the plane of maximal displacement of the radial head must be determined.

Surgical procedure: retrograde radial intramedullary nailing

Sharp or tapered stainless or titanium steel nails are used as they literally pin the epiphyseal–metaphyseal fragment, and provide a firm anchorage during the reduction manoeuvres.

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