Xu Wei, Robinson Kingsley
Centre for Biomedical Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey, UK.
Ann Biomed Eng. 2008 Mar;36(3):435-43. doi: 10.1007/s10439-007-9430-7. Epub 2008 Jan 16.
The insertion of an implant into a bone leads to stress/strain redistribution, hence bone remodeling occurs adjacent to the implant. The study of the bone remodeling around the osseointegration implants can predict the long-term clinical success of the implant. The clinical medial-lateral X-rays of 11 patients were reviewed. To eliminate geometrical distortion of different X-rays, they were converted into a digital format and geometrical correction was carried out. Furthermore, the finite element (FE) method was used to investigate how the bone remodeling was affected by the stress/strain distribution in the femur. The review of clinical X-rays showed cortical bone growth around the proximal end of the implant and absorbtion at the distal end of the femur. The FE simulation revealed the stress/strain distribution in the femur of a selected patient. This provided a biomechanical interpretation of the bone remodeling. The existing bone remodeling theories such as minimal strain and strain rate theories were unable to offer satisfactory explanation for the cortical bone growth at the implant side of the proximal femur, where the stress/strain level was much lower than the one in the intact side of the femur. The study established the correlation between stress/strain distribution obtained from FE simulations and the bone remodeling of the clinical review. The cortical bone growth was initiated by the stress/strain gradient in the bone. Through the review of clinical X-rays and FE simulations, the study confirmed that the bone remodeling in a femur with an implant was influenced by the stress/strain redistribution. The strain level and stress gradient hypothesis is presented to offer an explanation for the implanted cortical bone remodeling observed in this study.
将植入物植入骨内会导致应力/应变重新分布，因此在植入物附近会发生骨重塑。对骨整合植入物周围骨重塑的研究可以预测植入物的长期临床成功率。回顾了11例患者的临床内外侧X线片。为消除不同X线片的几何变形，将其转换为数字格式并进行几何校正。此外，采用有限元（FE）方法研究股骨中的应力/应变分布如何影响骨重塑。临床X线片回顾显示植入物近端周围皮质骨生长，股骨远端吸收。有限元模拟揭示了一名选定患者股骨中的应力/应变分布。这为骨重塑提供了生物力学解释。现有的骨重塑理论，如最小应变和应变率理论，无法对股骨近端植入物侧皮质骨生长提供令人满意的解释，该侧的应力/应变水平远低于股骨完整侧。该研究建立了有限元模拟获得的应力/应变分布与临床回顾的骨重塑之间的相关性。皮质骨生长由骨中的应力/应变梯度引发。通过临床X线片回顾和有限元模拟，该研究证实植入物股骨中的骨重塑受应力/应变重新分布的影响。提出应变水平和应力梯度假说来解释本研究中观察到植入皮质骨重塑。
