Department of Orthopaedic Surgery, National University Hospital, NUHS Tower Block, Level 11, 1E, Kent Ridge Road, Singapore, 119228, Republic of Singapore.
Department of Biomedical Engineering, National University of Singapore, Singapore, Republic of Singapore.
Med Biol Eng Comput. 2019 Aug;57(8):1823-1832. doi: 10.1007/s11517-019-01988-x. Epub 2019 Jun 14.
Harvesting bone graft from the proximal tibia is gaining popularity, with lower complication rates and adequate quantity of cancellous bone. The amount of harvested bone is dependent on the size of the cortical window introduced via osteotomy onto the proximal tibia, and its mechanical strength after surgery could be compromised. The aim of the study was to investigate the proximal tibia's mechanical stability after bone harvesting and the effect of varying window sizes using a validated finite element model. Two cadaveric tibiae were tested with bone strains measured for different circular cortical window diameters (10-25 mm). Sixteen finite element models of the intact and harvested tibia were simulated and validated with experimental data. The experimental and predicted max/min principal bone strains were fitted into regression models and showed good correlations. It was predicted the maximum principal bone stresses were greatest and concentrated at postero-inferior and antero-superior regions of the cortical window. A stress line progressed from the edge of the window to the posterior side of the tibia, which became more prominent with the increase of size of the cortical window. It was found that large circular osteotomies for bone harvesting at the proximal tibia induced stress concentrations and stress lines which could lead to eventual failure. Graphical abstract The formation of a stress line in the harvested tibia initiated from the postero-inferior edge of the window and progressed to the medial side. The stress line became more prominent with the increase of the size of the cortical window from 10 to 25 mm in diameter.
从胫骨近端采集骨移植物越来越受欢迎，因为这种方法的并发症发生率较低，松质骨的量也足够。采集的骨量取决于通过截骨术引入胫骨近端的皮质窗的大小，以及手术后的机械强度可能会受到影响。该研究的目的是通过使用经过验证的有限元模型来研究骨采集后胫骨近端的机械稳定性，以及不同窗口大小的影响。对两根尸体胫骨进行了测试，测量了不同圆形皮质窗直径（10-25 毫米）的骨应变。模拟了 16 个完整和采集胫骨的有限元模型，并将实验数据与预测数据进行了验证。实验和预测的最大/最小主骨应变拟合到回归模型中，相关性良好。预测最大主骨应力最大，集中在皮质窗的后下和前上区域。应力线从窗口边缘延伸到胫骨的后侧，随着皮质窗尺寸的增加，该应力线变得更加明显。研究发现，胫骨近端的大圆形截骨术用于采集骨会导致应力集中和应力线，这可能导致最终的失败。
