72.7 Ischaemia following a supracondylar fracture

This is a child who cannot move his fingers after the reduction of a supracondylar fracture. His arm shows some or all of these signs: (1) He has severe, deep, poorly localized, pain in the flexor muscles of his forearm. Pain when you extend his fingers passively is a serious late sign. So is flexion of his fingers. Occasionally, the syndrome is subacute and painless. (2) Paraesthesiae develop. First he feels ’pins and needles’, then his arm becomes numb with anaesthesia of glove distribution. (3) The skin of his arm (if his is conscious) becomes white or blue (if he is Caucasian). There is no circulation in his nail beds. (4) His arm is weak, and he cannot use his fingers. (5) Palpable induration of his forearm muscles is a diagnostic sign, but it occurs late. (6) His radial pulse may be weak or absent. An absent pulse is an unreliable sign, because the pulse is sometimes present even when there is severe ischaemia. Teach your staff the importance of the four ’Ps’—pain, paraesthesia, pallor (if they are caring for Caucasians) and paralysis, in that order.

Figure 72.11: FOREARM TRACTION is useful first treatment for ischaemia following a supracondylar fracture. Only if this fails to restore a child’s circulation need you explore his arm. A, traction in extension. B, Dunlop traction. B, is more widely recognized, A is easier and adequate. After Mercer Rang with kind permission.

Be vigilant, quick, and decisive. Recognize these signs early. If they are getting worse decompression is urgent. This is a very rare acute emergency, and there is no time to refer him. It is one of the few occasions where doing something is always better than doing nothing. If you are lucky, extending his forearm in traction, as in Fig. 72-11, will be enough to restore his circulation. If this fails, you will have to explore his antecubital fossa, and decompress the muscles of his arm. The penalty for not doing this will be Volkmann’s ischaemic contracture (70.4).

EARLY SIGNS OF IMPENDING ISCHAEMIC CONTRACTURE

Temporarily ignore the child’s fracture. Take off all bandages. If a plaster cast has been applied, remove it.

FOREARM TRACTION Apply longitudinal traction to the skin of the child’s forearm. Use adhesive strapping and pass the cord over a pulley, so that if he moves about, traction will still be maintained. Suspend his arm as in Fig. 72-11.

Slope his bed slightly to stop him falling out, by putting a pillow under one side of the mattress.

Monitor the circulation in his arm.

If the pain goes, his circulation improves, and he is able to move his fingers, continue traction. When most of the swelling has gone, usually in about a week, reduce the fracture as described above, and put his arm in a collar and cuff. You should now have no trouble with his pulse. Usually, by this time the fracture is so firmly fixed that you will have to accept the malposition.

CAUTION! If pain, paraesthesiae, pallor, and paralysis persist, for more than an hour, make preparations to take him to the theatre, explore his antecubital fossa and, if necessary, the volar aspect of his forearm, as described below. Don’t be put off by a full stomach (16.1).