Background: Distal ulna fracture fixation plates commonly cause irritation, necessitating removal, due to the narrow area between the ulna articular cartilage and the extensor carpi ulnaris. This study defines the safe zone for plate application and determines whether wrist position affects risk of impingement. Methods: Four different distal ulna anatomic plates (Acumed, Medartis, Skeletal Dynamics, and Synthes) were applied to 12 cadaveric specimens. Safe zone size was measured in circumferential distance and angular arc. Impingement was examined in flexion and extension in neutral, pronation, and supination. Results: The distal ulna safe zone has dimensions of a 92° arc and perimeter circumference of 15 mm. Cumulative extensor carpi ulnaris (ECU) impingement occurred in 0% of the 6 simulated wrist/forearm positions for the Acumed plate, 22% for the Synthes plate, 31% for the Skeletal Dynamics plate, and 68% for the Medartis plate. Impingement was most common in supination. Likelihood of ECU impingement significantly decreased in the following order; Medartis > Skeletal Dynamics > Synthes > Acumed. Conclusion: The ECU tendon’s mobility can cause impingement on ulnarly placed distal ulna plates. Intra-operative testing should be performed in supination. Take home points regarding each plate from the 4 different manufacturers: contouring of Medartis plates, when placed ulnarly, is mandatory. The Acumed plate impinged the least but is not designed for far-distal fractures. The Synthes plate is least bulky but not suitable for proximal fractures. The Skeletal Dynamics plate appeared the most versatile with a reduced incidence of impingement compared to other ulnarly based plates.
LoganAJLindauTR. The management of distal ulnar fractures in adults: a review of the literature and recommendations for treatment. Strategies Trauma Limb Reconstr. 2008;3(2):49-56.
2.
FaiermanEJupiterJB. The management of acute fractures involving the distal radio-ulnar joint and distal ulna. Hand Clin. 1998;14(2):213-229.
3.
RichardsTADealDN. Distal ulna fractures. J Hand Surg Am. 2014;39(2):385-391.
4.
HazelANemethNBindraR. Anatomic considerations for plating of the distal ulna. J Wrist Surg. 2015;4(3):188-193.
5.
KobayashiMGarcia-EliasMNagyL, et al. Axial loading induces rotation of the proximal carpal row bones around unique screw-displacement axes. J Biomech. 1997;30(11-12):1165-1167.
6.
UerpairojkitCKittithamvongsPPuthiwaraD, et al. Surgical anatomy of the dorsal cutaneous branch of the ulnar nerve and its clinical significance in surgery at the ulnar side of the wrist. J Hand Surg Eur Vol. 2019;44(3):263-268.
7.
GotoAKunihiroOMuraseT, et al. The dorsal cutaneous branch of the ulnar nerve: an anatomical study. Hand Surg. 2010;15(3):165-168.
8.
PoublonARKraanGLauSP, et al. Anatomical study of the dorsal cutaneous branch of the ulnar nerve (DCBUN) and its clinical relevance in TFCC repair. J Plast Reconstr Aesthet Surg. 2016;69(7):983-987.
9.
Das DeSJohnsenPHWolfeSW. Soft tissue complications of dorsal versus volar plating for ulnar shortening osteotomy. J Hand Surg Am. 2015;40(5):928-933.
10.
AhsanZSSongYYaoJ. Outcomes of ulnar shortening osteotomy fixed with a dynamic compression system. J Hand Surg Am. 2013;38(8):1520-1523.
11.
PomeranceJ. Plate removal after ulnar-shortening osteotomy. J Hand Surg Am. 2005;30(5):949-953.
12.
ChenNCWolfeSW. Ulna shortening osteotomy using a compression device. J Hand Surg Am. 2003;28(1):88-93.
13.
MegerleKHellmichSGermannG, et al. Hardware location and clinical outcome in ulna shortening osteotomy. Plast Reconstr Surg Glob Open. 2015;3(10):e549.
14.
LohYCVan Den AbbeeleKStanleyJK, et al. The results of ulnar shortening for ulnar impaction syndrome. J Hand Surg Br. 1999;24(3):316-320.
15.
ElgammalARozeeB. Outcomes of the ulnar shortening osteotomy using a dynamic compression plate on the ulnar surface of the ulna. J Wrist Surg. 2018;7(4):344-349.
