Single column locking plate fixation is inadequate in two column acetabular fractures. A biomechanical analysis

Nicholas J Giori,Arthur T Lee,Philipp Leucht,Derek P Lindsey,Kiarash Khajavi,Michael J Bellino

doi:10.1186/1749-799x-5-30

Nicholas J Giori, Arthur T Lee + Show 4 more

Open Access

https://doi.org/10.1186/1749-799x-5-30

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Abstract

BackgroundThe objective of this study was to determine whether one can achieve stable fixation of a two column (transverse) acetabular fracture by only fixing a single column with a locking plate and unicortical locking screws. We hypothesized that a locking plate applied to the anterior column of a transverse acetabular fracture would create a construct that is more rigid than a non-locking plate, and that this construct would be biomechanically comparable to two column fixation.MethodsUsing urethane foam models of the pelvis, we simulated transverse acetabular fractures and stabilized them with 1) an anterior column plate with bicortical screws, 2) an anterior locking plate with unicortical screws, 3) an anterior plate and posterior column lag screw, and 4) a posterior plate with an anterior column lag screw. These constructs were mechanically loaded on a servohydraulic material testing machine. Construct stiffness and fracture displacement were measured.Result and DiscussionWe found that two column fixation is 54% stiffer than a single column fixation with a conventional plate with bicortical screws. There was no significant difference between fixation with an anterior column locking plate with unicortical screws and an anterior plate with posterior column lag screw. We detected a non-significant trend towards more stiffness for the anterior locking plate compared to the anterior non-locking plate.ConclusionIn conclusion, a locking plate construct of the anterior column provides less stability than a traditional both column construct with posterior plate and anterior column lag screw. However, the locking construct offers greater strength than a non-locking, bicortical construct, which in addition often requires extensive contouring and its application is oftentimes accompanied by the risk of neurovascular damage.

Highlights

Intraarticular acetabular fractures are commonly treated with open reduction and internal fixation
In conclusion, a locking plate construct of the anterior column provides less stability than a traditional both column construct with posterior plate and anterior column lag screw
We found that constructs with two column fixation were statistically stiffer than an anterior column plate alone

Summary

Introduction

Intraarticular acetabular fractures are commonly treated with open reduction and internal fixation. Transverse acetabular fractures, as defined by Letournel and Judet [1], extend intraarticularly across both the anterior and posterior column of the pelvis, and divide the pelvis into a superior segment containing the roof and intact ilium and an inferior segment consisting of a single ischiopubic segment. Internal fixation of these fractures often involves a combination of plates and screws to maintain perfect reduction. We hypothesized that a locking plate applied to the anterior column of a transverse acetabular fracture would create a construct that is more rigid than a non-locking plate, and that this construct would be biomechanically comparable to two column fixation

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