Percutaneous Screw Fixation For The Fractures Of Femoral Neck With Assisted By ISO-C2D Computer Navigation System:An Experimental Study

Part I Quantitative Anatomic Basis of Percutaneous Screw Fixation For the Fractures of Femoral NeckObjective:To observe and measure the parameter of proximal femur Anatomy, for percutaneous screw Fixation for the fractures of femoral neck.Methods:90dried femur specimens were included in this study. the angle of inclination of the posterior the femoral neck was measured and recorded as the posterior slant angle (Angle a).30femur specimens were made into section and the projection of these section was determined. By measuring the borders of the projection, the projective line of anterior and posterior borders of the femoral neck in the head of femur was determined. According to the results acquired from this study, the projective parameters(Angle β、Angle θ) were acquired. The data were expressed as Mean±Standard Deviation and analyzing the data by using the descriptive methods with SPSS13.0, explored the "safe area" in femoral neck fractures surgery.Results:The proximal femoral femoral is irregular bone, and each part has some morphological character. Angle a:64.00±2.31°, Angle β (29.93±2.87°)、Angle θ (50.62±2.69°. Through analyzing the angle of inclination of the posterior the femoral neck and the projective line of the femoral neck anterior and posterior borders in the head of femur and using anatomical knowledge,"safe area" in femoral neck fractures surgery can be established.Conclusions:The surgical safy area of the proximal femur is useful for determining the orientation and direction of the operation of percutaneous screw fixation for the fractures of femoral neck. Part II Experiment of Internal Fixations For the Fractures of Femoral Neck with Iso-C2D Computer Navigation SystemObjective:To investigate the methods and application value of CAOSS (computer assisted orthopedic surgery system) in the percutaneous screw fixation for the fractures of femoral neck.Methods:Divide the30femoral skeleton specimens into two groups, three cancellous screws were fixed in each of15fracture models with traditional standard fluoroscopy or Iso-C2D computer navigation system guidance randomly. The angle of screw deviation from cervicofemoral angle and femoral neck anteversion was accessed by calculating an index from the angles measured on the AP and lateral views of X-ray film, and the position of the screws was evaluated by direct measurement of the transverse section of femoral neck and femoral head, and assigned a score based on deviation from ideal screw position, The drilling Attempts were documented.Results:Statistical analysis of the angle of screw deviation, screw spread within the femoral neck, and drilling Attempts showed that the average screw deviation and screw spread were significantly better in the computer-assisted navigation group(P<0.05)than those in the conventional operation group. And drilling attempts in the navigation group was also lower.Conclusions:Computerized navigation technology combined with the surgical safy area of the proximal femur can effectively assist the fixation of the cannulated screws in the treatment of femoral neck fractures, it improves the accuracy of cannulated screw placement and results in fewer drilling attempts.