Background: Plate and screw fixation during the treatment of distal humeral fracture in adults is considered to be a gold standard that makes anatomic and articular reduction. Injury of the ulnar nerve is a common condition that can be found in pre-operative, intraoperative, and postoperative. Intraoperative anterior subcutaneous transposition is still a controversial issue.

Objective: To understand the variation of distance of the ulnar nerve during elbow motion with the anatomical landmark of distal humeral bone and plate position after fixation.

Materials and Methods: The authors have studied ten fresh adult cadavers, who underwent autopsy at the Department of Forensic Medicine of Srinakharinwirot University.

Results: The results showed that in zone 2, the Center of the medial condyle was the position of the distal humeral bone with the most variation in position changing during elbow flexion/extension. In the sagittal plane (+2.56 to –4.58 mm), the mean difference equaled to 7.14 mm, while in the coronal plane (+1.70 to –5.14 mm), the mean difference equaled to 6.84 mm, with the highest percentage of irritation up to 70%. Furthermore, 14 cases of ulnar nerve subluxation were found in 20 studies (70%).

Conclusion: From the present study, the Medial condyle was the landmark with the most irritation and position changing of ulnar nerve during elbow flexion. The incidence of ulnar subluxation occurred after in situ release for plate fixation was also found higher than in previous studies.

Keywords: Plate and screw fixation; Ulnar nerve injury; Distal humeral fracture; Anterior subcutaneous nerve transposition; Cadaveric study; Anatomical bony landmark of distal humeral bone; Ulnar nerve subluxation

DOI: doi.org/10.35755/jmedassocthai.2021.06.12321

Received 18 December 2020 | Revised 9 April 2021 | Accepted 20 April 2021