ABSTRACT
BACKGROUND: After internal fixation is applied to femoral shaft fracture with medial cortical defect, the fixation device is often bended and broken due to the stress on it. So far, reliable methods have not been found to solve this problem in clinic.OBJECTIVE: To evaluate the biomechanical stability of the allograft bone plate after a bony defect of the medial cortex is reconstructed with allograft bone plate.DESIGN: A randomized controlled experimental study.SETTING: This trial was conducted in the Department of Orthopaedics, the 175 Hospital of Chinese PLA, and Laboratory of Biomechanics, First Military Medical University of Chinese PLA.PARTICIPANTS: This trial was conducted in Laboratory of Medical Biomechanics, First Military Medical University. MTS858 Biomix biomaterial testing machine was used to simulate model of femoral shaft fracture on 3male adult femurs donated voluntarily by their relatives, aged 23, 24 and 28years old.INTERVENTIONS: The fracture model of medial cortical defect was made in the femurs. Different kinds of fixation were applied and the results were compared between fixated femurs and the normal ones. The fixations included steel plate fixation(fixation for group 1 ), steel plate with allograft bone plate fixation(fixation for group 2), steel plate with allograft bone plate fixation and reduction of the medial cortical fragment(fixation for group 3).MAIN OUTCOME MEASURES: The vertical compression displacement under 500 N load, three-point bending strength under 10 N and anti-torsional angle under 300 N load are all measured.RESULTS: The vertical compression displacement and three-point bending strength of the control group were insignificantly different from those of the fixation group 3 ( P ＞ 0.05), but significantly different from those of the fixation group 1 and 2 ( P ＜ 0.05). The anti-torsional angle of the control group was significantly different from that of the three fixation groups( P ＜ 0. 05) . The result of fixation in fixation group 1 was the worst, better in fixation group 2and the best in fixation group 3.CONCLUSION: When there is a medial cortical defect in the femur, reconstruction with a bone plate can recover the integrity of the femoral medial cortex, and the successful rate of the plate internal fixation is increased.