Biochemical Finite Element Analysis of the Locked Kirschner Wire System Versus Volar Plate Fixation of Distal Radius Fracture

Abstract

Background: Volar locking plate (VP) and Kirschner wire (K-wire) fixations of distal end radius fractures are the most frequently used techniques that produce similar long term clinical results. However, inadequate fixation strength of the K-wire may cause pin loosening or migration. Although these complications can be prevented by immobilization, joint stiffness and a prolonged recovery period can occur.
 Objective: Herein, a technique that provided more stability, allowing immediate motion after fixation by linking the K-wires into a single system (locked K-wire system) was proposed.
 Methods: We evaluated biomechanical responses of the locked K-wire system and a VP in extraarticular distal radius fracture models AO/OTAa type 23A2 and 23A3 using three-dimensional finite element analysis. All models were tested under axial, bending, and torsional loads.
 Results: From the simulation results, the total displacement was greater in the dorsal wedge fracture than that from the simple fracture under all loads for both fixation systems. The locked K-wire system and the VP could withstand immediate physiologic load with maximum displacements of 1.15 mm and 1.39 mm, respectively.
 Conclusion: Considering the immediate physiologic load resistance and the ability to preserve its position during the bone-healing period, the locked K-wire system might be used as an alternative to fix distal radius fractures.