Symptomatic Idiopathic Ulnar Nerve Instability in the Elbow Diagnostic Considerations and 1-Year Outcomes After Anterior Transposition of Ulnar Nerve.

Background: Symptomatic idiopathic ulnar nerve instability (IUNI) in the elbow is an uncommon condition characterized by symptoms of ulnar neuritis resulting from frictional injury to the ulnar nerve from repetitive subluxation out of the cubital tunnel. This study reports the 1-year clinical outcomes after treatment of IUNI with anterior transposition of the ulnar nerve.

Methods: This is a retrospective case study of five patients. Ulnar nerve instability was diagnosed clinically based on the presence of ulnar neuritis symptoms in combination with a positive "ulnar nerve push past" test. Electromyography (EMG) was performed on all patients. After failure of nonsurgical treatment, five patients underwent anterior subcutaneous transposition of the ulnar nerve at the elbow. Clinical outcome scores and time to resolution of symptoms were recorded at a minimum follow-up of 12 months.

Results: The mean age of the patients at the time of surgery was 37.8 years (range: 18 to 57 years). The mean duration of symptoms prior to surgery was 15.7 ± 4.9 months. All five patients reported neuritis symptoms in the distribution of ulnar nerve in the hand and had ulnar nerve instability in the cubital tunnel on clinical examination. All patients were symptom free within 6 months after anterior transposition of the ulnar nerve.