Stokes Ian A F, Aronsson David D, Dimock Abigail N, Cortright Valerie, Beck Samantha
Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont 05405-0084, USA.
J Orthop Res. 2006 Jun;24(6):1327-34. doi: 10.1002/jor.20189.
Sustained mechanical loading alters longitudinal growth of bones, and this growth sensitivity to load has been implicated in progression of skeletal deformities during growth. The objective of this study was to quantify the relationship between altered growth and different magnitudes of sustained altered stress in a diverse set of nonhuman growth plates. The sensitivity of endochondral growth to differing magnitudes of sustained compression or distraction stress was measured in growth plates of three species of immature animals (rats, rabbits, calves) at two anatomical locations (caudal vertebra and proximal tibia) with two different ages of rats and rabbits. An external loading apparatus was applied for 8 days, and growth was measured as the distance between fluorescent markers administered 24 and 48 h prior to euthanasia. An apparently linear relationship between stress and percentage growth modulation (percent difference between loaded and control growth plates) was found, with distraction accelerating growth and compression slowing growth. The growth-rate sensitivity to stress was between 9.2 and 23.9% per 0.1 MPa for different growth plates and averaged 17.1% per 0.1 MPa. The growth-rate sensitivity to stress differed between vertebrae and the proximal tibia (15 and 18.6% per 0.1 MPa, respectively). The range of control growth rates of different growth plates was large (30 microns/day for rat vertebrae to 366 microns/day for rabbit proximal tibia). The relatively small differences in growth-rate sensitivity to stress for a diverse set of growth plates suggest that these results might be generalized to other growth plates, including human. These data may be applicable to planning the management of progressive deformities in patients having residual growth.
持续的机械负荷会改变骨骼的纵向生长，而这种生长对负荷的敏感性与生长过程中骨骼畸形的进展有关。本研究的目的是量化在一组不同的非人类生长板中，生长改变与不同程度的持续改变应力之间的关系。在三种未成熟动物（大鼠、兔子、小牛）的生长板中，于两个解剖位置（尾椎和胫骨近端），对大鼠和兔子的两个不同年龄阶段，测量软骨内生长对不同程度的持续压缩或牵张应力的敏感性。使用外部加载装置8天，将生长测量为安乐死之前24小时和48小时施用的荧光标记之间的距离。发现应力与生长调节百分比（加载生长板与对照生长板之间的百分比差异）之间存在明显的线性关系，牵张促进生长，压缩减缓生长。不同生长板对应力的生长速率敏感性为每0.1MPa 9.2%至23.9%，平均为每0.1MPa 17.1%。椎骨和胫骨近端对应力的生长速率敏感性不同（分别为每0.1MPa 15%和18.6%）。不同生长板的对照生长速率范围很大（大鼠椎骨为30微米/天，兔子胫骨近端为366微米/天）。一组不同生长板对应力的生长速率敏感性差异相对较小，这表明这些结果可能适用于包括人类在内的其他生长板。这些数据可能适用于规划对仍有生长的患者进行进行性畸形的管理。
