To analyze related factors of radial nerve palsy in patients with humeral shaft fractures.

We reviewed 107 paients with humeral shaft fracture between January 2000 and June 2007. Thirteen patients had radial nerve palsy after trauma and 9 patients after the operation. We analyzed contributing factors of radial nerve palsy associated with humeral shaft fracture including the cause of trauma, location and pattern of fracture, surgical approach and tourniquet application in cases of plate fixation, the exploration for the nerve and the time for operation.

The difference in the incidences of radial nerve palsy after trauma and operation was not significant according to the location and pattern of fracture. The tendency of higher rate of radial nerve palsy after trauma in oblique or comminuted fractures, and after operation in spiral fractures was observed. The operation using intramedullary nailing and radial nerve exploration significantly reduced the incidence of radial nerve palsy after operation (p=0.01 and p=0.02). Posterior approach in open reduction and plate fixation showed a tendency of lower incidence of radial nerve palsy after operation (p=0.78). In logistic regression analysis, radial nerve exploration was the only significant factor that reduced the possibility of radial nerve palsy after operation (17.27: odds ratio, p=0.02).

In humeral shaft fractures, we should take into consideration whether intramedullary nailing is possible or not. In cases of anterior or anterolateral approach of open reduction and plate fixation, radial nerve should be carefully inspected. In most cases, we recommend radial nerve exploration in order to minimize the possibility of radial nerve palsy after operation.