Indrekvam K, Gjerdet N R, Engesaeter L B, Langeland N
University of Bergen, Surgical Research Laboratory, Norway.
Acta Orthop Scand. 1991 Dec;62(6):582-6. doi: 10.3109/17453679108994501.
This study was undertaken to explore the association between mechanical and chemical effects of intramedullary reaming and nailing. The right femora of 80 rats were reamed and nailed with steel nails. Forty rats were evaluated from 3 days to 24 weeks postoperatively. The other 40 rats had the nail removed after 12 weeks, and they were then followed from 3 days to 24 weeks after nail extraction. Evaluation consisted of in vivo strain recording, geometric measurements, mechanical three-point bending test, and chemical analyses of hydroxyproline and calcium contents. Reaming and nailing caused immediate weakening of the bone as measured by in vitro mechanical tests, but within 3 weeks the mechanical properties were fully restored, whereas in vivo strain remained reduced throughout the experimental period in rats with nails. Removing the nail increased in vivo strain to a level close to that of the intact femur. Remodeling of the bone resulted in greater external anteroposterior diameter, cross-sectional area, area moment of inertia, and amount of hydroxyproline and calcium in the operated on femur as compared with the intact side. This indicates that the repair processes resulted in greater bone mass of the operated on femur than of the intact femur. Thus, there is evidence that nailing techniques effectively assist tissues by repair and remodeling.
本研究旨在探讨髓内扩髓和钉固定的机械效应与化学效应之间的关联。用钢钉对80只大鼠的右侧股骨进行扩髓和钉固定。对40只大鼠在术后3天至24周进行评估。另外40只大鼠在12周后取出钢钉，然后在取钉后3天至24周进行随访。评估包括体内应变记录、几何测量、机械三点弯曲试验以及羟脯氨酸和钙含量的化学分析。通过体外力学试验测量，扩髓和钉固定导致骨骼立即变弱，但在3周内力学性能完全恢复，而在有钢钉的大鼠中，体内应变在整个实验期间持续降低。取出钢钉后，体内应变增加到接近完整股骨的水平。与完整侧相比，骨骼重塑导致手术侧股骨的前后外径、横截面积、面积惯性矩以及羟脯氨酸和钙的含量增加。这表明修复过程导致手术侧股骨的骨量大于完整股骨。因此，有证据表明钉固定技术通过修复和重塑有效地辅助了组织。
