Gorski J M, Schwartz L
Clin Orthop Relat Res. 1986 Jan(202):302-6.
Non-cemented press fit prostheses require a high degree of surgical precision for success. Since components vary in size by millimeters, the optimum preoperatively-determined size becomes a vital factor in selecting the correct size at the time of surgery. The preoperatively-determined component size is useful only if the information is obtained in a reliable and reproducible manner. The proper sequence combines X-rays of known magnification and templates of corresponding magnification. X-ray magnification is not a constant value even if the X-ray tube is maintained at a standardized height. Variables such as patient size and positioning make magnification measurements a necessity for every X-ray taken. A dense lead plate was designed for this purpose because commercially-available devices are over-penetrated by the X-ray exposures routinely used for hip roentgenograms. Manufacturers can provide templates in varying magnifications. This makes it possible to obtain a high correlation between the preoperative choice and the actual size chosen at surgery.
非骨水泥压配式假体的成功植入需要高度的手术精准度。由于组件尺寸相差仅几毫米，术前确定的最佳尺寸成为手术时选择正确尺寸的关键因素。只有以可靠且可重复的方式获取信息，术前确定的组件尺寸才有用。正确的流程是结合已知放大倍数的X射线和相应放大倍数的模板。即使X射线管保持在标准高度，X射线放大倍数也不是一个恒定值。患者体型和体位等变量使得每次拍摄X射线时都必须进行放大倍数测量。为此设计了一块致密铅板，因为用于髋关节X线片的常规X射线曝光会使市售设备过度穿透。制造商可以提供不同放大倍数的模板。这使得术前选择与手术时实际选择的尺寸之间能够高度相关。
