松质骨螺钉骨水泥强化的生物力学和组织学研究

目的通过动物实验观察不同骨水泥强化松质骨螺钉的生物力学和组织学变化动态,为骨质疏松骨折患者内固定提供理论基础。方法在10只杂种犬胫骨近端制作松质骨螺钉植入的动物模型,分别采用碳酸化羟基磷灰石水泥(CHC)和聚甲基丙烯酸甲酯(PMMA)强化,分别于术后5d、4、8、12和16周处死动物,观察螺钉拔出的生物力学和组织学变化。结果CHC强化的螺钉拔出力随手术后时间的延长而逐渐升高,16周时达到(512.5 14.5)N,而PMMA强化组螺钉拔出力则随手术后时间的延长而逐渐降低。CHC-骨界面结合紧密,并且随时间延长出现CHC降解和骨长入,而PMMA-骨界面形成一层纤维组织。结论CHC强化能够提高松质骨螺钉植入体内的稳定性,并且随植入时间延长而逐渐升高。

Augmentation of cancellous screw with bone cement: a biomechanical and histological study

Objective To observe biomechanical and histological dynamic changes of cancellous screws augmented with different kinds of bone cement in order to provide evidence for internal fixation of osteoporotic fracture. Methods Cancellous screws were implanted in the proximal tibias of 10 mongrels to make animal pull out models. The screws were augmented with carbonated hydroxyapatite cement (CHC) or polymethylmethacrylate (PMMA) respectively. The animals were sacrificed at 5 days, 4, 8, 12, and 16 weeks after surgery to investigate the biomechanical and histological changes in screw pull out. Results The pull out force of screws augmented with CHC increased along with the experimental time, and reached (512.5 14.5)N at 16 weeks postoperatively. But the screws augmented with PMMA showed reverse results. The interface between bone and CHC was closely fitted,and the implanted CHC was replaced by new bone gradually. But the interface between bone and PMMA was a layer of fibrous tissue. Conclusion When the cancellous screws are augmented with CHC, the in vivo stability can be strengthened and increased along with the time.