Entrapment of the proximal fragment of supracondylar fractures.

Supracondylar fracture of the humerus in children may be associated with nerve and vessel injury (Thomas and Alpar 1987). Sometimes attempts at manipulative reduction are unsuccessful. Recent papers have discussed treatment of displaced fractures by traction (Worlock and Colton 1984; Piggot, Graham and McCoy 1986). We report four cases in whom the neurovascular bundle and the biceps tendon came to lie behind the flared distal end of the proximal fragment and hence between it and the distal fragment. Case 1. A nine-year-old boy sustained a grossly displaced supracondylar fracture ofthe left humerus. The proximal fragment tethered the overlying skin, beneath which it was palpable. The distal pulses were impalpable. Manipulative reduction was unsuccessful. Exploration through an anterior lazy S incision revealed the proximal flared fragment of the humerus to have cut through brachialis and then passed between the median nerve and the biceps tendon, impaling the brachial artery. The proximal fragment was now gripped by the median nerve and intermuscular septum medially and the biceps tendon laterally. Traction tightened the grip. With the gripping structures held aside, the proximal fragment was reduced into line with the distal fragment and secured with Kirschner wires. A vein patch was applied to the damaged artery and a fasciotomy of the forearm compartments carried out. One year later he had full functional recovery and symmetrical carrying angles, but has required a z-plasty for the anterior scar. Case 2. A five-year-old boy sustained a grossly displaced supracondylar fracture of the left humerus. The proximal fragment tethered the skin of the anticubital fossa, beneath which it was palpable. Manipulation of the fracture caused temporary obliteration ofthe radial pulse, as traction was applied. Exploration revealed the same anatomical disarrangement as in the first case, except that the brachial artery lay with the median nerve behind and medial to the proximal fragment (Fig. 1). By holding the gripping structures aside, reduction was achieved