Factors associated with radial nerve palsy after operative treatment of diaphyseal humeral shaft fractures

BackgroundThe radial nerve is at risk after diaphyseal humeral fracture or surgery to repair the fracture. We hypothesized that there are no factors associated with iatrogenic radial nerve palsy and, secondarily, that there are no factors associated with traumatic radial nerve palsy or radial nerve palsy of any type.MethodsWe analyzed 325 adult patients who underwent operative treatment of a diaphyseal humerus fracture at 6 hospitals between January 2002 and November 2014 to determine factors associated with a radial nerve palsy. We excluded patients with pathologic fractures, fractures with massive bone loss, prior surgery in another hospital, periprosthetic fractures, and if no operative note was available.ResultsIn patients without a traumatic radial nerve palsy, an iatrogenic radial nerve palsy occurred in 18 of 259 diaphyseal humeral fractures (7%). The surgical approach was associated with iatrogenic radial nerve palsy (P = .034). No factors were associated with traumatic radial nerve palsy (66 of 325 patients [20%]) of the humeral diaphysis. Open fractures, location of fracture, and high-energy trauma were significantly associated with radial nerve palsy of any type (84 of 325 patients [26%]).ConclusionsPatients and surgeons should keep in mind that iatrogenic transient dysfunction of the radial nerve will occur in approximately 1 in 5 patients treated with lateral exposure of the humerus, in 1 in 9 patients treated with posterior exposure, and in 1 in 25 patients with an anterolateral exposure.