High-resolution ultrasound in etiological evaluation of ulnar neuropathy at the elbow.

OBJECTIVE: Ulnar neuropathy at the elbow (UNE) involves mechanical compression and irritation of the ulnar nerve (UN) caused by environmental and dynamic abnormalities that can however also be found in asymptomatic patients. Using high-resolution ultrasound, we aimed to assess and compare the relevance of morphological and dynamic variants of the UN and its surrounding structures (UN abnormalities) in symptomatic and asymptomatic patients.

METHOD: UN abnormalities in patients with UNE were assessed using high-resolution ultrasound and compared against unaffected arms (patients or healthy volunteers).

RESULTS: We studied 234 arms of 117 individuals (89 with UNE and 145 control). Eighty-one percent of the arms with UNE compared to 40% of control (p=0.00001) showed UN abnormalities. While it was dislocated in 49% of arms with UNE compared to in 23% of control (p=0.004).

CONCLUSION: The two-fold higher frequency of occurrence of UN abnormalities in arms with UNE indicates their causative or at least contributory role in such neuropathies. High-resolution ultrasound should be part of the initial evaluation of UNE in order to assess the etiology of the conflict.