1509 - Neuromuscular Ultrasound in Severe Ulnar Neuropathy with Permanent Nerve Dislocation

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

LO

Lauren O'Keefe, MD

Resident Physician
University of Texas Southwestern
Dallas, Texas, United States

Co-Author(s)

CS

Casey Salandra, DO

Resident Physician
University of Texas Southwestern
Dallas, Texas, United States

Corresponding Author(s)

HC

Haibi Cai, MD

Assistant Professor
University of Texas Southwestern Medical Center
Dallas, Texas, United States

Co-Author(s)

DK

Daniel Koehler, MD

Associate Professor of Orthopaedic Surgery
University of Texas Southwestern Medical Center
Dallas, Texas, United States

Submitter(s)

LO

Lauren O'Keefe, MD

University of Texas Southwestern
Dallas, Texas, United States

Case Diagnosis: A 62-year-old man presented with progressive right hand weakness and numbness in the fourth and fifth digits, years after an elbow fracture with post-traumatic osteoarthritis. Exam revealed claw hand and intrinsic muscle atrophy and dense sensation loss over digits 4 and 5. Electrodiagnostic testing (EDX) showed severe right ulnar neuropathy at the elbow. Neuromuscular ultrasound (US) demonstrated the ulnar nerve was enlarged with loss of fascicular architecture anddislocated anterior to the medial epicondyle. There was bony overgrowth between the medial epicondyle and olecranon. The diagnosis was tardy ulnar nerve palsy due to chronic compression and anatomical distortion following trauma.

Case Description: EDX confirmed ulnar neuropathy at the elbow with slowed conduction velocity across the elbow with severe axonal loss and active denervation. US showed a hypertrophic ulnar nerve permanently dislocated due to osteophyte formation. The patient underwent subfascial ulnar nerve transposition and anterior interosseous nerve transfer. Intraoperatively, the nerve was found anterior to the epicondyle with a neuroma in continuity. Early postoperative recovery showed improving neurological function.

Discussions: Tardy ulnar nerve palsy occurs long after elbow trauma, often due to deformities like osteophytes or nerve displacement. US offers dynamic visualization of nerve position and architecture. In this case, it revealed permanent anterior subluxation, which guided the surgical plan to perform transposition of the ulnar nerve into a superficial position distanced from the arthritic elbow. The severe axonal loss on EDX aided in the decision to augment the patient’s recovery with anterior interosseous nerve transfer at the level of the distal forearm.

Conclusions: US complemented EDX by identifying the exact location and structural cause of ulnar compression. Its role in this case was essential for surgical planning. Integrating ultrasound into routine assessment of ulnar neuropathy enhances diagnostic accuracy and informs management, especially in post-traumatic or anatomically complex presentations.