Optimal configuration of a dual locking plate for femoral allograft or recycled autograft bone fixation: A finite element and biomechanical analysis

Abstract

Background: Allografts and recycled bone autograft are commonly used for biological reconstruction. The dual locking plates fixation method has been advocated for increasing allograft stability and preventing fixation failure; however, the biomechanical properties of the various configurations of dual locking plates have not been extensively studied.

Methods: In a finite element (FE) analysis, we developed 6 patterns of different dual locking plate configurations for fixation of the mid shaft of the femur. The maximum strains were recorded for each of the 6 models then axial, bending and torsion stiffness were calculated. The FE analysis was validated the results with mechanical testing (axial compression, bending, and torsional stiffness) on a cadaveric femur.

Findings: The highest axial compression (715.41 N/mm) and lateral bending (2981.24 N/mm) was found in Model 4 (with two 10-hole locking plates placed at the medial and lateral side), while the highest torsional stiffness (193.59 N·mm /mm) was found in Model 3 (with 8- and 10-hole locking plates placed at the posterior and lateral side). Excellent agreement was found between the finite element analysis and biomechanical testing (r² = 0.98).

Interpretation: The dual locking plate configuration with medial and lateral, 10-hole locking plates provided the most rigid and strongest fixation of the femur; both in terms of axial compression and lateral bending stiffness.

Keywords: Allograft; Biomechanical analysis; Dual locking plating; Femur; Finite element analysis; Recycled bone autograft.