What's the best surgical repair technique of an ulnar styloid fracture? A biomechanical comparison of different techniques

Introduction: 8-10% of all Ulnar styloid fractures (USF) accompanying distal radius fractures are addressed surgically. The surgical fixation has to counteract forces of translation and rotation acting on the distal radioulnar joint (DRUJ). The different technics used were never compared biomechanically. Our study aims to compare the effects of different techniques of USF fixation on the forearm rotation and the dorsal -palmar (DP)-translation of the DRUJ. Material and methods: 9 forearm specimens were mounted on a custom testing system. Load was ap-plied for Pronosupination and DP-translation with the forearm placed in neutral position, pronation and supination. The positional change of the DRUJ was measured using a MicroScribe. Six different, sequential conditions were tested in the same specimen: intact, USF and 4 repair techniques (2 K-wire, tension band wiring (TBW), headless compression screw, suture anchor). Results: The USF significantly increased DP-translation and pronosupination compared to the intact con-dition. The DP-translation in neutral was reduced significantly with all four techniques compared to the USF condition. TBW and suture anchor also showed a significant difference to the K-wire fixation. In supination only the TBW and suture anchor significantly decreased DP-Translation. The rotational stabil -ity of the DRUJ was only restored by the K-wire fixation and the TBW. Conclusions: All four USF repair techniques partially restored translational stability; however, only K-wire fixation and TBW techniques restored rotational stability. TBW was biomechanically superior to the other techniques as it restored translational stability and rotational stability. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Ulnar styloid fractures (USF) in the presence of distal radius fractures often require surgical treatment to counteract forces on the distal radioulnar joint (DRUJ). Biomechanical comparison of different techniques showed that tension band wiring (TBW) and suture anchor were superior in restoring both translational and rotational stability of the DRUJ.