The Mechanical Testing of the New Internal Fixator for the Distal Femoral Fracture after Total Knee Arthroplasty

• Main Authors: Chan-Tsung Yang, 楊展宗
• Other Authors: Cheng-Kung Cheng
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/34317515909796195989

碩士 === 國立陽明大學 === 醫學工程研究所 === 88 === The management of ipsilateral distal femoral (supracondylar) fracture after total knee arthroplasty (TKA) is still a controversial to the orthopaedic surgeon. Although there were some fixators for the stabilization of supracondylar femoral fracture and biomechanical test were investigated, there were few studies made with the fractures after TKA. This study had tried to design a new internal fixator for the fracture of distal femur after TKR. The biomechanical test was conducted to compare the mechanical properties (axial and torsional stiffness) of the femur which were restabilized by different fixators(DCP, GSH and new design). The new fixator was designed with an intramedullary nail to be fixed on the femoral component of the total knee prosthesis. So there is no movement between the two pieces of the implants. Therefore, this new internal fixator could have greater structure stiffness by increasing the structure contact area. To test this improvement, the femoral component was implanted on the artificial composite bone (composite bone, SAWBONESR, USA) and made a mimic supracondylar femoral fracture(transverse pattern). The fractures were fixed with new designed fixator or traditional DCP plate or GSH nail(five samples in each group). The axial compression test and torsional test were done by the MTS Bionix858 to compare the mechanical stability of these fixators with intact bone(no fracture) and prosthesis implanted bone(no fracture). There is no significant difference between each group in axial stiffness, which means that these three fixators can stabilize the fracture effectively in the longitudinal direction. All three fixation groups (Nail, Plate, New) are lower than the no fracture group (Intact, Prosthesis) with significant difference. But the torsional stiffness of the new designed foxator is higher than the DCP plate and GSH nail.