Injuries of the axillary nerve

Axillary nerve injury can complicate trauma to the shoulder. Loss of active shoulder abduction indicates additional injury to the suprascapular nerve, rotator cuff or skeletal structures. Neurophysiological testing and magnetic resonance imaging help to define the injury. Axillary nerve palsy after dislocation of the glenohumeral joint recovers spontaneously in a large number of cases. There is a higher risk of disruption of the axillary nerve in cases presenting without recorded dislocation of the shoulder. In all cases, it is important to look for evidence of nerve continuity 2–3 months after injury. If nerve injury is associated with displaced fracture of the proximal humerus, then the nerves should be explored and internal fixation of the fracture performed. When continuity of the axillary nerve is in doubt, exploration of the nerve should be performed by 3 months after injury. If spontaneous recovery is unlikely, then repair is indicated, most commonly with a nerve graft. Transfer of a triceps branch of the radial nerve is an alternative, which may be appropriate in late-presenting cases. Reported outcomes suggest that in more than 70 % of cases it is possible to achieve a strength in the deltoid muscle of grade 3 or better according to the Medical Research Council scale. There are few options for late reconstruction of shoulder abduction, these giving only limited gain in function.