Vanderby R, Manley P A, Belloli D M, Kohles S S, Thielke R J, McBeath A A
Division of Orthopaedic Surgery, School of Veterinary Medicine, University of Wisconsin, Madison.
Proc Inst Mech Eng H. 1990;204(2):97-109. doi: 10.1243/PIME_PROC_1990_204_238_02.
The purpose of this study was to investigate if experimental strain analysis is predictive of femoral adaptation after total hip replacement (THR). Ten large adult dogs underwent unilateral THR with identical implants. Five implants were press fit for porous ingrowth fixation, and five were cemented. Four months after surgery femora were harvested. Strain gauge rosettes were applied to the femora at eight proximal locations. Femora were compressively loaded on the head of the femur or femoral component. Strain data represented three conditions: preoperative, acutely postoperative, and four-month postoperative. The unoperated femur of each dog was used to simulate preoperative and acutely postoperative behavior of the contralateral implanted femur. Strains from each condition were compared. Transverse femoral sections were obtained through the levels of the strain gauges. Fine detailed radiographs were used to quantify morphological changes. Results showed cemented and uncemented implantations produce similar trends but different amounts of bone adaptation. Adaptations were generally consistent in direction with strain perturbations caused by implantation, but the extent of adaptation did not strongly correlate with the magnitude of perturbations. Also, there was no consistent trend towards normalization of altered strains. Results suggest that strain perturbations after THR may be mechanical triggers for morphological changes, but caution is required when predicting the extent of these changes or the autoregulatory role of strain.
本研究的目的是调查实验性应变分析是否能够预测全髋关节置换术（THR）后股骨的适应性变化。十只成年大型犬接受了单侧全髋关节置换术，植入相同的假体。五只假体采用压配式多孔生长固定，五只采用骨水泥固定。术后四个月采集股骨。在股骨近端的八个位置应用应变片。对股骨头部或股骨假体施加压缩载荷。应变数据代表三种情况：术前、术后急性期和术后四个月。每只犬未手术的股骨用于模拟对侧植入股骨的术前和术后急性期的情况。比较每种情况下的应变。通过应变片所在水平获取股骨横断面。使用精细的X光片量化形态学变化。结果显示，骨水泥固定和非骨水泥固定植入产生相似的趋势，但骨适应性变化的程度不同。适应性变化的方向通常与植入引起的应变扰动一致，但适应性变化的程度与扰动的大小没有强烈的相关性。此外，应变改变没有一致的正常化趋势。结果表明，全髋关节置换术后的应变扰动可能是形态学变化的机械触发因素，但在预测这些变化的程度或应变的自动调节作用时需要谨慎。
