# A Dual-Thread Lag–Locking Screw Enhances Single Lateral Plate Fixation in Bicondylar Tibial Plateau Fractures: A Biomechanical Study

## TL;DR

A new screw design improves stability in complex tibial fractures compared to traditional methods, offering a less invasive treatment option.

## Contribution

A dual-thread lag-locking screw is introduced to enhance fixation in bicondylar tibial plateau fractures.

## Key findings

- DLLP achieved significantly greater interfragmentary compression than SLLP during screw insertion.
- DLLP showed higher maximum failure force and better resistance to lateral displacement compared to SLLP.
- DLLP constructs survived 1 million cycles of dynamic fatigue loading, while SLLP constructs failed prematurely.

## Abstract

Schatzker type V bicondylar tibial plateau fractures present a major challenge due to the difficulty of achieving stable fixation with minimally invasive strategies. This study introduces a dual-thread lag and locking plate (DLLP) design that integrates lag screw compression with unilateral locking plate fixation. A custom-built compression evaluation platform and standardized 3D-printed fracture models were employed to assess biomechanical performance. DLLP produced measurable interfragmentary compression during screw insertion, with a mean displacement of 1.22 ± 0.11 mm compared with 0.02 ± 0.04 mm for conventional single lateral locking plates (SLLPs) (p < 0.05). In static testing, DLLP demonstrated a significantly greater maximum failure force (7801.51 ± 358.95 N) than SLLP (6224.84 ± 411.20 N, p < 0.05) and improved resistance to lateral displacement at 2 mm (3394.85 ± 392.81 N vs. 2766.36 ± 64.51 N, p = 0.03). Under dynamic fatigue loading simulating one year of functional use, all DLLP constructs survived 1 million cycles with <2 mm displacement, while all SLLP constructs failed prematurely (mean fatigue life: 408,679 ± 128,286 cycles). These findings highlight the critical role of lag screw compression in maintaining fracture stability and demonstrate that DLLP provides superior biomechanical performance compared with SLLP, supporting its potential as a less invasive alternative to dual plating in the treatment of complex tibial plateau fractures.