Stability of femoral prosthesis after total hip replacement / 中国组织工程研究

ABSTRACT

BACKGROUND:There are many experimental studies about compression mechanics of femur after hip replacement at home and aboard. Therefore, it is very important to study the torque, torsion angle, load-displacement relationship of femur after hip replacement. Comparing and analyzing the properties of compression and torsional mechanics of traditional-type prosthesis and anatomical-type prosthesis is of important significance for studying hip replacement and the stability of artificial prosthesis. OBJECTIVE:To compare and analyze the stability of traditional-type prosthesis and anatomical-type prosthesis by stimulating femoral axial compression and torsion tests after hip replacement, so as to provide biomechanical parameters for clinic practice. METHODS: Twelve specimens of left- and/or right-side femur were selected. The femoral necks of 6 left-side femur specimens were retained as the anatomical-type titanium artificial joint prosthesis group, and the femoral necks of the 6 right-side femur specimens were removed as the traditional-type cobalt-chromium-molybdenum artificial joint prosthesis group. The femur specimens in these two groups were respectively placed onto the electronic universal testing machine workbench and were imposed compression stress at the experimental velocity of 5 mm/min. The corresponding displacement values were read under the force of 20, 40, 60, 80 and 100 N. And then, both ends of the femur specimens from these two groups were placed within the chuck of torsion testing machine, and were imposed torque at the experimental velocity of 1(°)/s. The corresponding torsion angle values were read under the torque force of 5, 10, 15 and 20 N?m. RESULTS AND CONCLUSION: Under the external force of 100 N, the displacement was (2.03±0.06) mm in the traditional-type prosthesis group, and (1.83±0.05) mm in the anatomical-type prosthesis group. Under the torque force of 20 N?m, the torsion angle values of traditional-type prosthesis was (21.7±0.7)°, and that of anatomical-type prosthesis was (13.2±0.4)°. The displacement under the external force of 100 N and the torsion angle values under the torque force of 20 N?m in the anatomical-type prosthesis group were al significantly less than those in the traditional-type prosthesis group (P < 0.05). These results suggest that traditional-type and anatomical-type prostheses have different compression and torsion mechanical properties. The anatomical-type femur prosthesis has a better stability than traditional-type femur prosthesis.