Ulnar Nerve Injury in Pediatric Midshaft Forearm Fractures: A Case Series

Objectives: To describe a midshaft forearm fracture pattern that places the ulnar nerve at risk in the pediatric population and provide 7 clinical case examples describing the injury pattern and treatment methods. Design: Retrospective observational case series, review of literature, cadaver dissection, and treatment recommendations. Setting: Multi-institutional, Southeast United States. Patients: Seven pediatric patients (5 male and 2 female) with mean age of 8.7 years (range, 3-14) who sustained a significantly displaced closed, or grade I open, middle to distal one-third both-bone forearm fracture with subsequent ulnar nerve dysfunction. Interventions: Manual reduction and casting of both-bone forearm shaft fractures, operative debridement, fracture fixation, nerve exploration, neurolysis, nerve repair, and nerve grafting. Main Outcome Measurements: Radiographic fracture union, clinical ulnar nerve motor and sensory function testing, along with selective electric nerve testing and advanced imaging were monitored throughout follow-up postinjury. Results: Five of 7 patients underwent surgical treatment and 2 others were treated with conservative measures. The ulnar nerve was entrapped within the fracture site of one patient with an open fracture along with partial nerve transection, and 4 patients were found to have the nerve encased in hypertrophic scar tissue or bony callus upon surgical exploration at 3-12 months postinjury. Conclusions: The ulnar nerve lies in a precarious position in the middle to distal one-third forearm and is bound by anatomic constraints that place the nerve at risk of injury. This article offers a treatment algorithm that includes conservative treatment, acute exploration, early exploration (<= 3 months), and late exploration (>3 months).