Authors

Theddy F Slongo, James B Hunter

Injuries to the elbow are common in childhood. Extraarticular (supracondylar) and intraarticular (condylar) fractures must be distinguished. To the inexperienced eye, the diagnosis may be difficult due to the many apophyses. A reliable, indirect sign of an intraarticular injury is the “fat pad sign” or lipohemarthrosis. Comparative x-rays should be avoided as they do not compensate for a lack of anatomical knowledge. In supracondylar fractures, the presence or absence of malrotation will be decisive for the choice of treatment. Ultrasound examination is increasingly used, especially for intraarticular fractures in young children.

a Supracondylar fracture.

b After closed reduction, percutaneous K-wire fixation can be performed with wires introduced from the medial and lateral side. Care must be taken to avoid the ulnar nerve. The wires must cross within the bone and should aim to traverse the olecranon fossa. Thus, each wire engages four cortices.

c If two K-wires are used from the lateral side, 2.0 mm wires must be used. These must diverge so that one engages the medial column having crossed the olecranon fossa. The second wire should be more vertical, engaging the lateral column. The wires should cross outside the bone.

In general, reduction should be followed by percutaneous K-wire stabilization, as extreme positions to maintain reduction are associated with compartment syndrome. The configuration of wires can be crossed or lateral. If only lateral wires are used, care must be taken to stabilize both columns; largediameter wires should be used (at least 2 mm), and a third wire may be required.

Antegrade ESIN from the deltoid insertion can be used but is technically difficult: It is best performed using two image intensifiers and by surgeons experienced in ESIN techniques. The technique does allow early mobilization, as there are no wires across the joint.

Baumann’s angle is the angle between the lateral condylar physis and the long axis of the humerus shaft. After reduction and fixation, Baumann’s angle should be equal to that of the uninjured side (usually 70–75°). More than 75° denotes varus malposition. Correct rotational alignment is best judged on a lateral view x-ray.

Condylar fractures

Fractures of the lateral humeral condyle are Salter-Harris type IV injuries. The diagnosis can often be quite difficult, particularly when the medial fracture line only goes as far as the thick cartilage. Completely displaced fractures are, as a rule, easy to recognize and must be treated by open reduction and internal fixation, either with a metaphyseal lag screw or two diverging K-wires. The stability of the elbow joint should be checked after fixation. The approach can be lateral or posterolateral. It is imperative to ensure that the blood supply to the fragments, which are covered to a large extent by cartilage, is not destroyed.

a Lateral condylar fracture of the distal humerus (Salter-Harris type IV).

b If the metaphyseal fragment is large enough, a metaphyseal lag screw can be inserted via a posterolateral approach.

c In younger children, K-wires can be used and should be inserted exactly as illustrated.

A displaced fracture that has been missed inevitably results in pseudarthrosis. This can lead to cubitus valgus and ulnar nerve problems, or cubitus varus through instability and overgrowth of the lateral condyle.

Injuries of the medial condyle are extremely rare. The trochlea  ossifies late, which can be mistaken for an epicondyle fracture. The treatment corresponds to that of the lateral condyle. A combination of fractures of both the lateral and medial condyle leads to a Y-fracture, an injury that usually only occurs in older children. In contrast to adults, they seldom have intraarticular comminution. Unstable T-fractures should be treated by open reduction in the usual manner from a posterior approach, whereas in younger children, after the fixation of both articular fragments, a K-wire fixation is sufficient. The joint and physis must be fixed precisely.

Medial epicondyle fractures

Fractures of the medial epicondyle are mostly the result of an elbow dislocation which has reduced spontaneously. In these cases, recognizing the dislocation and the fractured epicondyle can be difficult. Occasionally, this is displaced within the joint and incongruity of the joint should lead to the diagnosis. The degree of displacement of the medial epicondyle that requires fixation is still being debated. Less than 0.5 cm of displacement can be accepted. More than 1 cm cannot be accepted, as instability of the elbow may result.

Apophyseal injury to the medial epicondyle of the distal humerus. K-wires are used in younger children, but in a nearly mature child a screw should be used. Great care is needed to ensure a smooth surface over which the ulnar nerve will lie.