Science News: Is There an Association Between Ulnar Nerve Hypermobility and Neuropathy at the Elbow?

Published March 20, 2022

Education Science News

Submitted by: Rebecca O’Bryan, MD
Edited by: Francisco Gomez, MD

Frost G, Varey P, Haldane C, Lee T, Finlayson H. Is there an association between ulnar nerve hypermobility and neuropathy at the elbow? Arch Phys Med Rehabil. 2021;102(11):2231-2238. doi:10.1016/j.apmr.2021.02.021

Summary: This is a review of literature regarding associations between ulnar nerve hypermobility (UNH) and ulnar neuropathy at the elbow (UNE). Case control, cohort, and RCTs were included. Studies diagnosing UNH both with physical exam (3) and US (17) were included. Diagnosis was made with both electrodiagnostic studies and ultrasonography. Studies looking at post op findings, hereditary neuropathy with liability to pressure palsy, polyneuropathy, trauma, and pediatric cases were included. Cadaveric or animal studies were excluded.
20/645 studies met inclusion criteria, of which 18 were prospective. 17 of included studies stratified cases as stable, subluxation, or dislocation of the ulnar nerve. Analysis revealed no association between UNH and UNE. However, post hoc analysis of cross-sectional areas (CSA) of the ulnar nerve in seven studies revealed that the difference in CSA between stable and UNH was doubled in the patients with UNE vs. those without. It was posited that this may indicate that a more severe UNE may develop in those with UNH, although sample sizes were underpowered for statistical analyses.
Comments: While we do not always share review articles, this one caught my eye, as the topic of UNH as either protective (Michelin et al hypothesis that UNH may prevent excessive pressure in the cubital tunnel) or alternatively a risk factor leading to more severe UNE is a topic of hot debate.
This review lends credence to the view that overall, UNH is not associated with increased risk of UNE, but that perhaps when UNE does develop in those with UNH, it may be more severe (higher CSA of the ulnar nerve). This was a well-done review, and applicable to most clinicians with an interest in peripheral neuropathy.
Article of similar interest:
Leis AA, Smith BE, Kosiorek HE, Omejec G, Podnar S. Complete dislocation of the ulnar nerve at the elbow: A protective effect against neuropathy? Muscle Nerve. 2017 Aug;56(2):242-246. doi: 10.1002/mus.25483. Epub 2017 Jan 4. PMID: 27859367.