Finite element biomechanical evaluation of internal fixation methods for metacarpal shaft fractures under multiple factors

Metacarpal shaft fractures often require surgical correction of displacement, angulation, or rotational deformities to restore function. Kirschner wires (K-wires), plates, and intramedullary screw fixation each have advantages and limitations. However,inconsistent biomechanical evidence in existing studies has precluded definitive conclusions regarding the optimal fixation technique. This studycompared K-wires, plates, and intramedullary screw for metacarpal shaft fractures using finite element analysis (FEA). In normal bone, intramedullary screw matched plate stability under low loads but were inferior under high loads, K-wires performed poorest. In osteoporotic bone, intramedullary screw provided superior stability, stress distribution, and less stress shielding than plates or K-wires. These findings would offer valuable biomechanical insights for metacarpal fractures treatment.