72.12 Fracture of the lateral condyle of the humerus (children)

A young child aged 4 to 15 falls on his outstretched hand. His wrist extensors, which are attached to his lateral condyle, pull it away from his humerus. His elbow is swollen and will not move. You can rotate his forearm, showing that his radius is intact. The posteromedial side of his arm is not tender, showing that he has probably not got a supracondylar fracture. Sometimes his elbow is dislocated also.

This is a serious Type IV epiphyseal injury (69.6). It occurs at a younger age than an injury to the medial epicondyle, and the displaced fragment is larger. The fracture line runs from the middle of the articular surface of the child’s elbow upwards and laterally, isolating part of his trochlea, the whole of his capitulum, and often a small part of the shaft of his humerus, as in Fig. 72-15. Sometimes, there is only a little lateral shift which need not be reduced. More often, the lower fragment turns over completely inside the joint. If it is not reduced, it unites to the shaft with fibrous tissue, and growth in the lateral half of his epiphysis stops. The result is a severe valgus deformity of his elbow which increases until growth ceases. Distortion of the path of his ulnar nerve round his severely deformed elbow causes a late ulnar paralysis with wasting of the small muscles of his hand.

The X–rays of his elbow are difficult to interpret, because a large part of the fragment is cartilage and casts no shadow. An AP view shows that the epiphysis of his capitulum is missing; instead, there is an abnormal mass of bone on the outer side of his elbow. In a lateral view this may be hidden behind his humerus, but it is usually displaced anteriorly. If he is under 12, you will not see the centre of ossification for his displaced lateral epicondyle, because it will not yet have appeared. If in doubt compare the X–ray of the injured side with that of the normal one. Don’t mistake this injury for a supracondylar fracture!

FRACTURE OF THE LATERAL CONDYLE OF THE HUMERUS

IF THERE IS NO DISPLACEMENT relieve the child’s pain, if necessary, by aspirating his elbow joint (Fig. 72-4) using careful sterile precautions. Apply a backslab from his axIlla to his kunckles with his elbow in 60 of flexion and his wrist dorsiflexed. Mould the backslab closely round his elbow, and hold it in a sling.

Figure 72.18: FRACTURE OF THE LATERAL CONDYLE. If this injury is not treated correctly, it will be followed by a severe valgus deformity which increases until growth ceases. After Watson Jones with kind permission.

At 4 weeks replace the slab by a sling.

IF THERE IS DISPLACEMENT, suspend his arm in extension traction, as in Fig. 72-11, until the swelling is less. Find two assistants. Anaesthetize the patient.

Ask one assistant to apply traction to the child’s partly flexed forearm. Ask the other assistant to apply counter traction to his upper arm. Ask them to slightly adduct his arm at the same time, so as to widen the space on the lateral aspect of his elbow joint.

While they are applying traction and adduction, try to manipulate the fragment back into place in contact with his humerus.

If closed reduction is successful, immobilize his elbow in a plaster backslab as above. Mould the backslab round the lateral side of his elbow to keep the fragment in place.

If closed reduction fails, do all you possibly can to refer the child for open reduction immediately. This involves fixing the lateral fragment with two fine Kirschner wires. The penalty for not doing so is likely to be a fixed elbow always. If the fragment is not replaced, warn his parents that a progressive valgus deformity and ulnar paralysis may occur, and that he must return early, so that an ulnar nerve transposition can be done.

Figure 72.19: FRACTURE OF THE CAPITULUM is a rare adult injury. The arrow shows a large piece of the capitulum displaced anteriorly.

DIFFICULTIES WITH FRACTURES OF THE LATERAL CONDYLE

If 10 to 30 years later the patient complains of NUMBNESS AND TINGLING in the distribution of his ulnar nerve, followed by wasting of the small muscles of his hand, he has an ulnar nerve paralysis. Warn his parents that this may follow the progressive valgus deformity of his elbow many years later, because he may not connect it with his injury. His ulnar nerve should be moved anteriorly in his elbow before the small muscles of his hand start to waste.