Efficacy of radial styloid targeting screws in volar plate fixation of intra-articular distal radial fractures: a biomechanical study in a cadaver fracture model

Kousuke Iba,Takuro Wada,Tomoaki Kamiya,Toshihiko Yamashita,Mitsuhiro Aoki,Yasuhiro Ozasa

doi:10.1186/1749-799x-5-90

Kousuke Iba, Takuro Wada + Show 4 more

Open Access

https://doi.org/10.1186/1749-799x-5-90

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Abstract

BackgroundThe locking screws target the radial styloid, theoretically provide greater stability against radial styloid fragment. However, it is unknown whether the radial styloid locking screws increased the stability of the volar plating system fixation along the entire distal radius or not. In this study, we evaluated the stability of the volar plating system fixation with or without the radial styloid screws using a biomechanical study in a cadaver fracture model.MethodsSix matched pairs of fresh-frozen human cadaver wrists complete from the proximal forearm to the metacarpal bones were prepared to simulate standardized 3-part intra-articular and severe comminuted fractures. Specimens were fixed using the volar plating system with or without 2 radial styloid screws. Each specimen was loaded at a constant rate of 20 mm/min to failure. Load data was recorded and, ultimate strength and change in gap between distal and proximal fragments were measured. Data for ultimate strength and screw failure after failure loading were compared between the 2 groups.ResultsThe average ultimate strength at failure of the volar plate fixation with radial styloid screws (913.5 ± 157.1 N) was significantly higher than that without them (682.2 ± 118.6 N). After failure loading, the average change in gap between the ulnar and proximal fragment was greater than that between the radial and proximal fragment. The number of bent or broken screws in ulnar fragment was higher than that in radial fragment. The number of specimens with bent or broken screws in cases with radial styloid screws was fewer than that in the fixation without radial styloid screws group.ConclusionThe ulnar fragment is more intensively stressed than the radial fragment under axial loading of distal radius at full wrist extension. The radial styloid screws were effective in stable volar plate fixation of distal radial fractures.

Highlights

The locking screws target the radial styloid, theoretically provide greater stability against radial styloid fragment
In cases of volar plate fixation without radial styloid screws, both 2 ulnar fragment screws were broken while the radial fragment screws remained no broken
Both ulnar screws remained intact in cases of volar plate fixation with 2 radial styloid screws

Summary

Introduction

The locking screws target the radial styloid, theoretically provide greater stability against radial styloid fragment It is unknown whether the radial styloid locking screws increased the stability of the volar plating system fixation along the entire distal radius or not. Many clinical reports have locking plate which can be characterized by 2 or 3 distal locking screws that target the radial styloid to provide fixation of radial styloid fragments [11]. It is unknown whether the radial styloid screws increased the stability of the volar plating system fixation along the entire distal radius. The purpose of this study was to evaluate whether the distinctive screws targeting the radial styloid were effective in the stable fixation of distal radial fractures using a cadaver unstable intra-articular fracture model

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