Successful recovery of anterior interosseous nerve palsy caused by blunt trauma at the forearm level: a case report

Anterior interosseous nerve syndrome (AINS) is typically characterized by dysfunction of the pure motor branch of the median nerve, primarily affecting the flexor pollicis longus and the flexor digitorum profundus (FDP) of the index finger, and occasionally involving the FDP of the middle finger and the pronator quadratus. Although various etiologies such as compressive neuropathy and isolated neuritis have been proposed, the most recent review describes AINS as a form of neuralgic amyotrophy. Its treatment remains a matter of debate; the most frequently discussed approach is conservative treatment followed by surgical intervention above the medial epicondyle level if recovery is not achieved. In the case described herein, a hematoma resulting from blunt trauma at the forearm level compressed the anterior interosseous nerve (AIN), with clinical features and diagnostic findings very similar to those of typical AINS. Early surgical removal of the hematoma led to complete recovery without complications. Despite the current understanding of AINS pathophysiology and treatment, this case emphasizes the need to consider the possibility of AIN palsy due to forearm lesions. We report on the clinical course and successful treatment of this case to highlight this important consideration.