We report the case of a 28-year-old patient who developed acute transient brachial plexopathy secondary to surgical management of an atrophic clavicle nonunion. The treatment was conservative, with symptom resolution at 4 months after surgery. This is the first reported case with electromyographic and neuroconduction follow-up, demonstrating complete and spontaneous resolution of axonal damage. The limited number of cases reported in the scientific literature allows for exploring some underlying causes of the acute plexopathy depending on the nature of the non-union (hypertrophic or atrophic).