Neurovascular injury and displacement in type III supracondylar humerus fractures.

From July 1987 to January 1991, 59 consecutive type III supracondylar humerus fractures in children were identified at Children's Hospital, Boston. Twenty-nine patients (49%) had evidence of neurovascular compromise. The median nerve was involved in 15 (52%) of these patients and was associated with posterolateral displacement in 87% of cases. The radial nerve was involved in eight (28%) of these patients and was associated with posteromedial displacement in every case. Injuries to the brachial artery occurred in 11 (38%) of these patients and was associated with posterolateral displacement in 64% and posteromedial displacement in 36% of cases. We conclude that posterolateral displacement in type III supracondylar humerus fractures is strongly associated with median nerve injuries. Posteromedial displacement is responsible for injuries. Posteromedial displacement is responsible for injuries to the radial nerve in virtually every instance. Brachial artery injuries may occur with either type of displacement. Neurovascular injury is higher than previously reported in these fractures.