Author/Authors :
Hawi, Nael Trauma Department - Hannover Medical School (MHH) - Hannover , Germany , Harb, Afif Trauma Department - Hannover Medical School (MHH) - Hannover , Germany , Liodakis, Emmanouil Trauma Department - Hannover Medical School (MHH) - Hannover , Germany , Razaeian, Sam Trauma Department - Hannover Medical School (MHH) - Hannover , Germany , Krettek, Christian Trauma Department - Hannover Medical School (MHH) - Hannover , Germany , Welke, Bastian Laboratory for Biomechanics and Biomaterials - Department of Orthopaedic Surgery - Hannover Medical School - Hannover, Germany , Hurschler, Christof Laboratory for Biomechanics and Biomaterials - Department of Orthopaedic Surgery - Hannover Medical School - Hannover, Germany , Zhang, Dafang Department of Orthopaedic Surgery - Brigham and Women’s Hospital, USA
Abstract :
Biomechanical stability assessment of 3 different constructs for proximal fixation of a locking compression plate(LCP) in treating a Worland type C periprosthetic fracture after total shoulder arthroplasty.Methods. 27 Worland type C fracturesafter shoulder arthroplasty in synthetic humeri were treated with 14-hole LCP that is proximally fixed using the following: (1)1×1.5 mm cerclage wires and 2x unicortical-locking screws, (2) 3×1.5 mm cerclage wires, or (3) 2x bicortical-locking attachmentplates. Torsional stiffness was assessed by applying an internal rotation moment of 5 Nm and then after unloading the specimen,an external rotation moment of 5 Nm at the same rate was applied. Axial stiffness was assessed by applying a 50 N preload, andthen applying a cyclic load of 250 N, then increasing the load by 50 N each time, until a maximum axial load of 2500 N was reachedor specimen failure occurred.Results. With regard to internal as well as external rotational stiffness, group 1 showed a meanstiffness of 0.37 Nm/deg and 0.57 Nm/deg, respectively, group 2 had a mean stiffness of 0.51 Nm/deg and 0.39 Nm/deg, re-spectively, while group 3 had a mean stiffness of 1.34 Nm/deg and 1.31 Nm/deg, respectively. Concerning axial stiffness, group 1showed an average stiffness of 451.0 N/mm, group 2 had a mean stiffness of 737.5 N/mm, whereas group 3 had a mean stiffness of715.8 N/mm.Conclusion. Group 3 displayed a significantly higher torsional stiffness while a comparable axial stiffness to group 2.
