Heyman S J, Smith G K, Cofone M A
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104.
Am J Vet Res. 1993 Feb;54(2):210-5.
Ten coxofemoral joints from 5 dog cadavers were used to study the effect of coxofemoral positioning on passive hip laxity. A material test system was used to measure lateral translation when force was between 20 N of compression and 40 N of distraction. Using the orthogonal coordinate system imposed in this study, neutral position was empirically defined at 15 degrees of extension and 10 degrees of abduction, relative to the plane of the pelvis, and no internal or external rotation of the femur. The hips were mounted in a custom-designed jig that allowed 1 rotational degree of freedom (ie, either flexion/extension, adduction/abduction, or internal/external rotation), while holding the other 2 constant. Lateral translation of the hips was tested at 10 degrees intervals from 30 degrees of flexion to 70 degrees of extension, 40 degrees of adduction to 60 degrees of abduction, and 30 degrees of internal rotation to 40 degrees of external rotation. Lateral displacement was maximal at 10 degrees of extension, 20 degrees of abduction, and 10 degrees of external rotation, approximating the neutral coxofemoral position during stance. As the hips were rotated into extreme positions, the amount of lateral displacement occurring with the same applied load decreased significantly to 32.0 to 65.3% of the maximal displacement. Determining the position of the hip associated with maximal passive laxity in vitro is essential to the design of a precise and accurate clinical stress-radiographic method to quantitate joint laxity in dogs. Our results confirm earlier work that passive hip joint laxity is at a maximum with the hip approximately in a neutral weight-bearing position.
使用来自5具犬类尸体的10个髋关节来研究髋关节位置对被动性髋关节松弛的影响。当施加的力在20 N压缩力至40 N牵张力之间时，使用材料测试系统测量侧向平移。利用本研究中设定的直角坐标系，相对于骨盆平面，中立位根据经验定义为伸展15度和外展10度，且股骨无内旋或外旋。将髋关节安装在定制设计的夹具中，该夹具允许1个旋转自由度（即屈曲/伸展、内收/外展或内旋/外旋中的一种），同时保持另外两个自由度不变。在从屈曲30度至伸展70度、内收40度至外展60度以及内旋30度至外旋40度的范围内，以10度的间隔测试髋关节的侧向平移。侧向位移在伸展10度、外展20度和外旋1度时最大，接近站立时的髋关节中立位。随着髋关节旋转至极端位置，在相同施加负荷下发生的侧向位移量显著减少，降至最大位移的32.0%至65.3%。在体外确定与最大被动松弛相关的髋关节位置对于设计一种精确准确的临床应力放射学方法以量化犬类关节松弛至关重要。我们的结果证实了早期的研究结果，即髋关节被动松弛在髋关节大致处于中立负重位置时最大。
