# Biomechanical comparison of fixation techniques for associated both-column acetabular fractures requiring single (anterior or posterior) versus combined anterior–posterior approaches

## TL;DR

This study compares different surgical techniques for fixing complex hip fractures and finds that a single approach can be as effective as a combined approach.

## Contribution

The study introduces a new biomechanical comparison of fixation techniques for both-column acetabular fractures.

## Key findings

- Single column plate plus lag screw fixation showed comparable stability to both column plating.
- No significant differences were found between AP+PCS and PP+ACS techniques.
- STS loading caused higher motion and rotation than SLS loading across all techniques.

## Abstract

Comparative data on fixation techniques for associated both-column (ABC) acetabular fractures are scarce. Compared with both column plating (AP + PP) via a combined anterior–posterior approach, single column plate plus other column lag screw fixation obviates the need for a second surgical approach. In this study, we (1) developed a clinically relevant ABC fracture model and (2) biomechanically compared the fixation strength of single column plate plus other column lag screw fixation and both column plating.

An ABC fracture model was created using fourth-generation composite hemipelves. Three different ABC fracture fixation techniques were biomechanically compared: (1) anterior column plate plus posterior column screw fixation (AP + PCS), posterior column plate plus anterior column screw fixation (PP + ACS), and anterior column plate plus posterior column plate fixation (AP + PP). Both single-leg stance (SLS) and sit-to-stand (STS) loading protocols were applied (loads from 50 to 750 N, ramp: 100 N/s). Fracture gap motion (FGM) and relative interfragmentary rotation (RIFR) between the four main fracture fragments were analysed at 750 N using an optical 3D measurement system.

Single column plate plus other column lag screw fixation techniques (AP + PCS and PP + ACS) provided comparable fixation strength to AP + PP, as evidenced by similar or even lower FGM and RIFR values. Moreover, no significant differences in FGM and RIFR were found between AP + PCS and PP + ACS. Compared to SLS loading, STS loading resulted in higher mean FGM and RIFR between the posterior iliac wing and the posterior column fragment across all fixation techniques.

In our ABC fracture model, both column plate fixation (AP + PP) via a combined approach did not demonstrate superior biomechanical stability compared with single column plate plus other column lag screw fixation. The latter, however, requires only one approach, thereby reducing surgical time and approach-related morbidity, and appears preferable if reduction of both columns is achievable through a single approach.