Gloria Coden, MD
Resident
BJC/WUSTL
St. Louis, Missouri, United States
Michael Sookochoff, MD
Assistant Professor
Washington University Department of Orthopedics
St. Louis, Missouri, United States
Right ulnar neuropathy secondary to hardware malpositioning, failed ulnar nerve transposition, and ulnar nerve subluxation over the medial fixation plate.
Case Description:
70-year-old male with past surgical history significant for right comminuted intra-articular distal humerus fracture status-post open reduction internal fixation (ORIF) of right distal humerus and transposition of the ulnar nerve 3 years ago, who presented with persistent paresthesias in the medial forearm and hand into the 4th and 5th digits and pain the posterior lateral aspect of his elbow.
Examination of the right elbow demonstrates well-healed surgical incision. Strength testing demonstrates 5-/5 elbow extension, 4/5 first dorsal interosseous, and 5/5 pronation, supination, and wrist extension/flexion. Positive Tinel's anterior to the cubital tunnel. Decreased sensation in the ulnar nerve distribution.
Electrodiagnostic and sonographic evidence for ulnar neuropathy at the elbow that appears electrically moderate in severity. On sonographic evaluation, the ulnar nerve is noted to sit posterior to the medial epicondyle, abut against the medial fixation plate, and partially sublux on flexion. There is no electrodiagnostic evidence of cervical radiculopathy.
Discussions:
Typically, ulnar neuropathy after distal humerus ORIF occurs due to iatrogenic injury or compression of the ulnar nerve. Additionally, studies indicate that ulnar nerve transposition during ORIF may increase the risk of postoperative ulnar neuropathy. However, this case illustrates an example of hardware directly injuring the ulnar nerve by the ulnar nerve subluxing over a fixation plate during elbow flexion. This case also demonstrates how ultrasound can determine the cause of a patient’s symptoms, as electrodiagnostic testing alone was not sufficient to localize the etiology of this patient’s ulnar neuropathy, and magnetic resonance imaging was not possible due to hardware.
Conclusions:
Ulnar neuropathy can occur after distal humerus ORIF due to the ulnar nerve subluxing over the medial fixation plate without direct compression of the ulnar nerve.
