Ultrasonographic evaluation of ulnar nerve morphology in patients with ulnar nerve instability

• Published in: Muscle & nerve Vol. 69; no. 5; pp. 543 - 547
• Main Authors: Ahmadli, Narmin, Akgun, Kenan, Terlemez, Rana, Misirlioglu, Tugce Ozekli, Palamar, Deniz
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.05.2024; Wiley Subscription Services, Inc
• Subjects: Asymptomatic; cross‐sectional area; Dislocation; Elbow; Elbow - diagnostic imaging; Elbow Joint - innervation; Evaluation; Grooves; Humans; Instability; Mobility; Morphology; Nerves; Neuropathy; Probability theory; Stability; Stability analysis; Statistical analysis; Subgroups; Ulnar Nerve - diagnostic imaging; ulnar nerve dislocation; ulnar nerve instability; ulnar nerve subluxation; Ulnar Neuropathies - diagnostic imaging; Ultrasonography; cross‐sectional area; ulnar nerve dislocation; ulnar nerve instability; ulnar nerve subluxation
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.28058

Introduction/Aims Ulnar nerve instability (UNI) in the retroepicondylar groove is described as nerve subluxation or dislocation. In this study, considering that instability may cause chronic ulnar nerve damage by increasing the friction risk, we aimed to examine the effects of UNI on nerve morphology ultrasonographically. Methods Asymptomatic patients with clinical suspicion of UNI were referred for further clinical and ultrasonographic examination. Based on ulnar nerve mobility on ultrasound, the patients were first divided into two groups: stable and unstable. The unstable group was further divided into two subgroups: subluxation and dislocation. The cross‐sectional area (CSA) of the nerve was measured in three regions relative to the medial epicondyle (ME). Results In the ultrasonographic evaluation, UNI was identified in 59.1% (52) of the 88 elbows. UNI was bilateral in 50% (22) of the 44 patients. Mean CSA was not significantly different between groups. A statistically significant difference in ulnar nerve mobility was found between the group with CSA of <10 versus ≥10 mm2 (p = .027). Nerve instability was found in 85.7% of elbows with an ulnar nerve CSA value of ≥10 mm2 at the ME level. Discussion The probability of developing neuropathy in patients with UNI may be higher than in those with normal nerve mobility. Further prospective studies are required to elucidate whether asymptomatic individuals with UNI and increased CSA may be at risk for developing symptomatic ulnar neuropathy at the elbow.