Opitz A
Wien Klin Wochenschr Suppl. 1983;141:1-27.
Knowledge of the physiologic distribution of strain in bone is essential for a successful osteosynthesis by means of compression plate. This method guarantees optimum stability if the plate acts as a tension band. If the side of tensile stresses varies within the bone, strain may not only occur on the side of the plate but also on the opposite cortex. In such cases the distribution of pressure in the fracture gap is of special importance. For determining the distribution of strain on the radius, it is necessary to examine the forces caused by the flexor- and extensor muscles of the wrist and fingers. Additional forces come also from flexor- and extensor muscles of the elbow. The frame formed by the bow-shaped radius and the ulna is of further importance for the distribution of strain. Kind and amount of tension is fundamentally influenced by forearm rotation. Anatomic studies on post-mortem specimens showed how the direction of muscle action to wrist and fingers changed in relation to the position of a plate fixed to the proximal shaft of the radius. This already demonstrates possible variations in the bending forces caused by forearm rotation. An analysis of the distribution of strain in the forearm bones was carried out on a biomechanical model using strain gauges. This method allows the simulation of strain to the skeleton caused by muscle force and the influence of load. The distribution of strain can be studied on the same model in various different positions of elbow and forearm. Six muscles and two muscle groups were simulated by means of wire pulls with calibrated strain gauges; these muscles and muscle groups act, on account of the physiological cross section and their position, as bending forces to the forearm bones in a dorsovolar plane. The tensile force on radius and ulna were each controlled by three strain gauges in four sections. The characteristic quantities of these sections were determined by evaluation of the appropriate computertomograms. With the aid of three strain gauges per section it was possible to assess the strain at any one desired point. Distribution of strain was determined by pull to each "muscle" in the extreme position of forearm rotation and three different positions of flexion to the elbow. The tensile force was expressed on graphs as muscle tension of 2 kp/cm2 per cross section (ill. 6 to 12).(ABSTRACT TRUNCATED AT 400 WORDS)
了解骨骼中应变的生理分布对于通过加压钢板成功进行骨合成至关重要。如果钢板起到张力带的作用，这种方法可确保最佳稳定性。如果骨内拉应力的一侧发生变化，应变不仅可能出现在钢板一侧，还可能出现在相对的皮质骨上。在这种情况下，骨折间隙中的压力分布尤为重要。为了确定桡骨上的应变分布，有必要研究腕部和手指的屈肌和伸肌所产生的力。额外的力还来自肘部的屈肌和伸肌。由弓形桡骨和尺骨形成的框架对于应变分布也具有重要意义。张力的种类和大小从根本上受到前臂旋转的影响。对尸体标本的解剖学研究表明，相对于固定在桡骨近端骨干上的钢板位置，腕部和手指的肌肉作用方向如何变化。这已经证明了前臂旋转所引起的弯曲力可能存在变化。使用应变片在生物力学模型上对前臂骨骼中的应变分布进行了分析。这种方法可以模拟肌肉力量和负荷对骨骼产生的应变。可以在同一模型上研究肘部和前臂处于各种不同位置时的应变分布。通过带有校准应变片的钢丝拉力模拟了六块肌肉和两组肌肉；由于这些肌肉和肌肉群的生理横截面积及其位置，它们在掌背平面上作为前臂骨骼的弯曲力起作用。桡骨和尺骨上的拉力在四个部位分别由三个应变片控制。这些部位的特征量通过对相应计算机断层扫描的评估来确定。借助每个部位三个应变片，可以评估任何一个所需点的应变。通过在前臂旋转的极限位置以及肘部屈曲的三个不同位置对每个“肌肉”施加拉力来确定应变分布。拉力以图表形式表示为每平方厘米横截面2千帕的肌肉张力（图6至图12）。
