An analysis of different reconstruction techniques for the radius: a finite element analysis

Abstract

Pathological fractures due to metastatic bone disease frequently require palliative stabilization. While polymethylmethacrylate (PMMA) provides immediate mechanical stabilization, its limited bending and multiaxial properties raise concerns. Reinforcement strategies such as plate fixation, intramedullary nails, and metallic augmentation have been proposed, yet their mechanical behavior under physiological loading remains insufficiently characterized. This study aims to evaluate the mechanical performance of three reconstruction strategies for a proximal radial defect: PMMA alone, PMMA combined with titanium plate-and-screw construct, and PMMA reinforced with a steel K-wire. A patient-specific workflow integrated musculoskeletal multibody model and finite element analysis. Muscle forces and elbow joint reaction forces were calculated for a static 90° shoulder flexion under two loading conditions: no external load and 2 kg mass applied at the center of mass of the hand. These forces were applied in finite element analysis in reconstructed forearm, and peak von Mises stress and displacements were evaluated. In loading scenario, elbow joint reaction force reached 314.4 N, and maximum muscle force was 120.8 N. In the PMMA-only construct, peak stress increased from 4.0 MPa (no load) to 12.0 MPa (with load). Plate fixation increased peak stress to 14.9 MPa in the loading case. K-wire reinforcement resulted in lowest PMMA peak stress (23% less with respect to PMMA-only and 38% less compared to titanium plate) but produced more pronounced displacement (29%) compared to plate fixation strategy. These findings suggest complementary mechanical benefits: K-wire reinforcement most effectively reduced peak cement stress, whereas plate fixation provided superior global stiffness.