Grevsten S
Prosthet Orthot Int. 1978 Apr;2(1):3-7. doi: 10.3109/03093647809146289.
Comparative studies with the PTB-suction prosthesis and the ordinary PTB prosthesis have provided opportunities to analyze and understand some functional differences in the suspension of below-knee prostheses. In a roentgenological study of the stump-socket contact signficantly less vertical displacement in the PTB-suction prosthesis has been shown. A study of the pressure variations in the suction socket verified the theory of the necessary pressure gradient in the PTB-suction socket. Added negative pressure by muscle action was also observed. An electromyographic study suggested a muscular activity pattern in the suction prosthesis similar to that of a normal leg, as a contrast to the ordinary PTB prosthesis where simultaneous contractions of antagonistic muscles seemed to be the usual pattern. The latter is interpreted as a defence reaction. An optimal prosthesis has been deduced. It shall have a soft prosthetic socket with a perfect fit, a suction, adhesion and friction fixation and a pressure gradient between the skin and the socket wall with minimum compression distally. The plaster casting shall be done in a downward modelling manner making available space for soft tissue without compression.
对PTB吸着式假肢与普通PTB假肢进行的对比研究，为分析和理解膝下假肢悬吊方面的一些功能差异提供了契机。在一项关于残肢与接受腔接触的X射线研究中，结果显示PTB吸着式假肢的垂直位移明显更小。对吸着式接受腔压力变化的研究证实了PTB吸着式接受腔中必要压力梯度的理论。还观察到了肌肉活动产生的附加负压。一项肌电图研究表明，吸着式假肢中的肌肉活动模式与正常腿部相似，与之形成对比的是，普通PTB假肢中拮抗肌同时收缩似乎是常见模式。后者被解释为一种防御反应。由此推导出了一种理想的假肢。它应具有一个贴合良好的柔软假肢接受腔、吸着、黏附和摩擦固定方式，以及皮肤与接受腔壁之间的压力梯度，且在远端具有最小的压迫。石膏模型制作应以向下塑形的方式进行，为软组织留出无压迫的空间。
