Heuijerjans Ashley, Wilson Wouter, Ito Keita, van Donkelaar Corrinus C
Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600MB, Eindhoven, The Netherlands.
J Orthop Res. 2018 Nov;36(11):2911-2922. doi: 10.1002/jor.24101. Epub 2018 Jul 13.
Osteochondral resurfacing implants are a promising treatment for focal cartilage defects. Several implant-factors may affect the clinical outcome of this treatment, such as the implant material stiffness and the accuracy of implant placement, known to be challenging. In general, softer implants are expected to be more accommodating for implant misalignment than stiffer implants, and motion is expected to increase effects from implant misalignment and stiffness. 3D finite element models of cartilage/cartilage contact were employed in which implantation angle (0°, 5°, 10°) and implant material stiffness (E = 5 MPa, 100 MPa, 2 GPa) were varied. A creep loading (0.6 MPa) was simulated, followed by a sliding motion. Creep loading resulted in low maximum collagen strains of 2.5% in the intact case compared to 11.7% with an empty defect. Implants mostly positively affected collagen strains, deviatoric strains, and hydrostatic pressures in the adjacent cartilage, but these effects were superior for correct alignment (0°). The main effect of implant misalignment was bulging of opposing cartilage tissue into the gap caused by the misalignment. This increased collagen strains and hydrostatic pressures. Deviatoric strains were increased adjacent to the gap. Subsequent sliding initially increased strains for a stiff, misaligned implant, but generally sliding decreased strains. In conclusion, implants can decrease the detrimental effect of defects, but correct implant alignment is crucial, more than implant material stiffness. Implant misalignment causes a gap, causing potentially damaging cartilage deformation during prolonged loading, for example, standing, even for soft implants. Mild motion may positively affect the cartilage. © 2018 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:2911-2922, 2018.
骨软骨表面置换植入物是治疗局限性软骨缺损的一种很有前景的方法。几个植入物因素可能会影响这种治疗的临床效果，比如植入物材料的硬度以及植入位置的准确性，而后者已知具有挑战性。一般来说，较软的植入物预计比硬度更高的植入物更能适应植入物的不对准情况，并且运动预计会增加植入物不对准和硬度带来的影响。本研究采用了软骨/软骨接触的三维有限元模型，其中植入角度（0°、5°、10°）和植入物材料硬度（E = 5兆帕、100兆帕、2吉帕）有所变化。模拟了蠕变加载（0.6兆帕），随后是滑动运动。蠕变加载导致完整情况下最大胶原应变较低，为2.5%，而空缺损情况下为11.7%。植入物大多对相邻软骨中的胶原应变、偏应变和静水压力有积极影响，但这些影响在正确对准（0°）时更为显著。植入物不对准的主要影响是相对的软骨组织鼓入由不对准造成的间隙中。这增加了胶原应变和静水压力。间隙附近的偏应变增加。随后的滑动最初会增加刚性、不对准植入物的应变，但总体上滑动会降低应变。总之，植入物可以减少缺损的有害影响，但正确的植入物对准至关重要，比植入物材料硬度更重要。植入物不对准会造成间隙，在长时间加载（例如站立）过程中导致潜在的有害软骨变形，即使对于软植入物也是如此。轻微运动可能对软骨有积极影响。© 2018作者。《矫形外科研究杂志》由威利期刊公司代表矫形外科研究协会出版。《矫形外科研究杂志》36:2911 - 2922，2018年。
