锥形股骨柄假体与股骨髓腔初始固定的定量研究

目的 研究CT成像技术结合计算机编程能否定量评估生物型锥形柄与股骨髓腔的初始固定质量.方法 选择30例A型或B型股骨髓腔行生物型锥形股骨柄全髋关节置换的患者,拍摄术后2周内患髋正、侧位X线片,再运用CT进行横断面平扫,扫描条件:140 kV,层厚为5 mm,窗宽为2000,窗位为800.获得横断面图像后运用计算机编程将股骨柄按长度自上而下平均划分为1、2、3、4区,计算股骨柄各区与股骨髓腔压配接触的松质骨或皮质骨的表面积.将股骨柄与松质骨或皮质骨的距离小于0.5 mm界定为压配接触. 结果 X线片及CT横断面均显示股骨柄在股骨髓腔中可获得三点固定,即股骨柄在股骨近端的后侧、股骨柄中部的前侧及股骨柄远端的后侧获得与股骨髓腔皮质的直接接触.股骨柄与松质骨的压配接触而积在1～4区分别为1716、1003、574、269 mm~2.股骨柄与皮质骨的压配接触面积在1～4区分别为147、106、65、0 mm~2.股骨柄与股骨髓腔总的压配接触面积从1～4区逐渐减少,分别为1863、1109、639、269 mm~2,分别占股骨柄表面积的22.9%、13.6%、7.9%、3.3%. 结论 运用CT成像技术结合计算机编程能够较为精确地计算出股骨柄与股骨髓腔的压配接触面积,从而能够准确定量地评估生物型锥形柄与股骨髓腔的初始固定质量.

A quantitative study of initial stability of tapered femoral component at the proximal femur

Objective To study whether CT imaging technology combined with computer program-ming can be used to quantitatively evaluate the initial stability of the tapered femoral component at the proximal femur. Methods Thirty patients who had undergone total hip arthroplasty were included in this study.Anteroposterior and lateral radiographs and spiral CT scans were taken for their tapered stems of femoral component inserted into their medullary cavities of Type A or Type B. The sectional views of CT scans were programmed on computer for calculation of the contact areas between the 4 zones of the tapered stems and the cancellous and cortical bone at the medullary cavity. Results The X-rays and the sectional views of CT showed the 3-point fixation pattern was obtained by the femoral stems in the medullary cavity. The contact areas between the 4 zones of the tapered stems and the cancellous and cortical bone at the medullary cavity were 22. 9%, 13.6% 7.9%, and 3.3% respectively. Conclusion It is possible to use CT imaging combined with computer programming as a quantitative method to evaluate the contact areas between the tapered com-ponent and the proximal femur following total hip arthroplasty.