High resolution ultrasonography in the diagnosis of ulnar nerve lesions with particular reference to post-traumatic lesions and sites outside the elbow.

Objective: Recent studies suggest that high resolution ultrasonography (HRU) is useful in evaluating ulnar neuropathy (UN) at the elbow. These studies do not include UN outside the elbow and lesions related to previous trauma. We investigate diagnostic utility of HRU in UN at any location of traumatic and non-traumatic etiology.

Methods: Patients with clinically suspected and electrophysiologically defined UN at the elbow and outside the elbow were included. Nerve conduction studies (NCS) were compared with HRU. HRU defined UN in terms of change in cross-sectional area.

Results: Our retrospective analysis included 46 UN. In 25 cases both NCS and HRU localised neuropathy to the elbow. In 15 where NCS was abnormal but non-localising, HRU localised the lesion in 14, 7 outside the elbow. In three of these, HRU characterised further pathology (synovial osteochondromatosis (n=2), myositis ossificans (n=1). Cross-sectional area of the ulnar nerve at the sulcus significantly correlated with distal NCS parameters.

Conclusions: HRU is of greater use than NCS in the localisation of UN both at the elbow and outside the elbow and in UN related to previous trauma.

Significance: HRU is useful for the localisation of ulnar neuropathy.