Electrodiagnostic / Neuromuscular Medicine
Christopher Truong, MD
Resident Physician
University of Alabama at Birmingham
Birmingham, Alabama, United States
Nandan Patel, MD
Resident Physician
University of Alabama at Birmingham
Birmingham, Alabama, United States
Berdale Colorado, DO
Associate Professor, Assistant Dean, Vice Chair, Program Director
University of Alabama at Birmingham
Hoover, Alabama, United States
Sarah Lopes, DO
Assistant Professor
University of Alabama at Birmingham
Birmingham, Alabama, United States
Christopher Truong, MD
University of Alabama at Birmingham
Birmingham, Alabama, United States
Right ulnar neuropathy at the elbow (UNE) secondary to heterotopic ossification (HO), an uncommon complication of severe central nervous system injury.
Case Description:
A 64-year-old right-hand–dominant male with epilepsy, hypertension, alcohol use disorder, and prior stroke presented with aphasia and right hemiparesis due to a large left subdural hematoma and venous infarct. He underwent craniotomy and meningeal artery embolization, later complicated by respiratory failure (tracheostomy), dysphagia (PEG), and DVTs on apixaban.
During inpatient rehabilitation at 8 weeks, he developed right medial elbow pain radiating to the fourth and fifth digits, impairing self-care. Exam revealed limited motion, sensory loss in the ulnar distribution, and weakness (elbow flexion/extension 4/5, pronation/supination 4/5, thumb abduction 3/5, finger abduction 3/5). Radiographs demonstrated posterior HO near the cubital tunnel; ultrasound showed focal ulnar nerve enlargement (11 mm²). Electrodiagnostic testing confirmed UNE. Splinting, topical NSAIDs, and therapy improved pain.
Discussions: HO develops in 10–20% of patients after CNS injury, usually involving the hip or shoulder. Elbow involvement occurs in ~15–20% of cases. Nerve entrapment from HO is rare; UNE from elbow HO has been described only in isolated reports. Pathogenesis involves neuroinflammation, abnormal bone morphogenetic protein signaling, and immobilization. This case emphasizes a unique structural mechanism of UNE, demonstrated by combined ultrasound and electrodiagnostic testing. Recognizing HO as a potential compressive etiology expands the differential for post-CNS-injury neuropathy and highlights the importance of multimodal diagnostic evaluation.
Conclusions:
HO should be considered in new UNE after CNS injury, particularly with early elbow pain, motion loss, or focal bony change. Prompt imaging and electrodiagnostic testing can identify structural and functional pathology, guide safe interventions when pharmacologic options are limited, and raise new questions about neuropathic complications of HO.
