Study On Biomechanical Character And Clinical Effect Of New Dynamic Bidirectional Cannulated Screw Therapy For Femoral Neck Fracture

Objcctive: The treatment of the femoral neck fracture is the debating focus in clinical study. The object was to evaluate the biomechanical characters and clinical effect of new dynamic bidirectional cannulated screw so as to find an effective methods for the treatment of femoral neck fractures.Methods:(1)Biomechanical Experiment: 12 femoral neck specimens picked out the flexible tissue and the other disease were divided into two groups randomly,each of which was made into the same standard femoral neck fracture models and was internally fixed by tri-flange nail and new dynamic bidirectional cannulated screw respectively. After axial compression test, bending and torsion test were made,the results were got and analyzed.(2)Clinical material: 167 patients were treated femoral neck fracture in our hospital from 1992 to 2000. All patients were respectively treated with new dynamic bidirectional cannulated screw. 60 patients were followed-up and analyzed by Harris way.Results:(1) Experiment results: It indicated that new dynamic bidirectional cannulated screw was stronger than tri-flange in anti-compression, anti-bend and anti-torsion test. It provided resistance to stress and rotational force and enhanced healing of the fracture. New dynamic bidirectional cannulated screw might meet biomechanic needs.(2)Clinical outcomes: 60 patients were followed up for 7~15 years,mean 9.8 years. Fracture healing time and postoperative complications of the patients treated with new type screw were shorter than that have reported in many journal. The functional results of the hip joints were also better. Conclusion: The design of the new dynamic bidirectional cannulated screw accords with the demanding biomechanics of human body,and the design of current internal fixation in orthopedics which has reasonable mechanics structure. It can accelerate bone healing and do functional exercises early,and has many other advantages, such as less trauma,simpler manipulation,lower complication and better results. The new dynamic bidirectional cannulated screw is an effective method for the treatment of femoral neck fractures and worthy of popularization.