Finite Element Analysis Of Different Intramedullary Supports To Stabilize Disrupted Medial Column Instability Of Proximal Humerus Fractures

Objective: To compare the biomechanical characteristics of fibula,columnar cement,anatomic cement spacer combined with locking plate in the treatment of proximal humerus fractures with disrupted medial column instability by finite element analysis.Method: After establishing a three-dimensional finite element model of proximal humerus fracture with disrupted medial column instability,lateral locking plate(LLP),lateral locking plate combined with fibular shaft allograft(LLP-FS),and lateral locking plate combined with column cement spacer(LLP-CC),lateral locking plate combined with anatomic cement spacer(LLP-AC),and lateral locking plate combined with medial reconstruction plate(LLP-MRP)different internal fixation systems were implanted for assembly.Under normal and osteoporotic conditions,abductive,adductive,flexion,axial compression,and rotational loads were applied to the models.The biomechanical properties were evaluated and compared by comparing the structural strength,the maximum stress and stress distribution of the internal fixators,and the vertical displacement in the fracture region.Results: Compared with the LLP group,the biomechanical properties of the LLP-FS,LLP-CC and LLP-AC were improved in different degrees.Compared with the other two methods of intramedullary support,the overall structural stiffness of the LLP-AC group was significantly higher under various loads,the maximum stress in the plant was smaller,the stress distribution was more uniform,and the vertical displacement in the fracture region was minimal.Its biomechanical properties are closer to or even better than LLPMRP group.Conclusion: From the perspective of finite element,anatomic cement intramedullary support spacer can provide a strong and effective medial column support,which can better disperse the stress on the lateral locking plate and enhance the biomechanical properties of the lateral locking plate fixation system.Anatomic cement intramedullary support spacer combined with lateral locking plate can effectively treat proximal humerus fractures with disrupted medial column instability.