Zhu Guang-Duo, Guo Wan-Shou, Zhang Qi-Dong, Liu Zhao-Hui, Cheng Li-Ming
Department of Bone and Joint Surgery, China-Japan Friendship Hospital, Beijing 100029; Graduate School of Peking Union Medical College, Beijing 100730, China.
Chin Med J (Engl). 2015 Nov 5;128(21):2873-8. doi: 10.4103/0366-6999.168044.
Controversies about the rational positioning of the tibial component in unicompartmental knee arthroplasty (UKA) still exist. Previous finite element (FE) studies were rare, and the results varied. This FE study aimed to analyze the influence of the tibial component coronal alignment on knee biomechanics in mobile-bearing UKA and find a ration range of inclination angles.
A three-dimensional FE model of the intact knee was constructed from image data of one normal subject. A 1000 N compressive load was applied to the intact knee model for validating. Then a set of eleven UKA FE models was developed with the coronal inclination angles of the tibial tray ranging from 10° valgus to 10° varus. Tibial bone stresses and strains, contact pressures and load distribution in all UKA models were calculated and analyzed under the unified loading and boundary conditions.
Load distribution, contact pressures, and contact areas in intact knee model were validated. In UKA models, von Mises stress and compressive strain at proximal medial cortical bone increased significantly as the tibial tray was in valgus inclination >4°, which may increase the risk of residual pain. Compressive strains at tibial keel slot were above the high threshold with varus inclination >4°, which may result in greater risk of component migration. Tibial bone resection corner acted as a strain-raiser regardless of the inclination angles. Compressive strains at the resected surface slightly changed with the varying inclinations and were not supposed to induce bone resorption and component loosening. Contact pressures and load percentage in lateral compartment increased with the more varus inclination, which may lead to osteoarthritis progression.
Static knee biomechanics after UKA can be greatly affected by tibial component coronal alignment. A range from 4° valgus to 4° varus inclination of tibial component can be recommended in mobile-bearing UKA.
单髁膝关节置换术（UKA）中胫骨假体的合理定位仍存在争议。以往的有限元（FE）研究较少，且结果各异。本有限元研究旨在分析活动平台UKA中胫骨假体冠状面排列对膝关节生物力学的影响，并找出合适的倾斜角度范围。
根据一名正常受试者的图像数据构建完整膝关节的三维有限元模型。对完整膝关节模型施加1000 N的压缩载荷进行验证。然后建立一组11个UKA有限元模型，胫骨托的冠状面倾斜角度范围从外翻10°到内翻10°。在统一的加载和边界条件下，计算并分析所有UKA模型中的胫骨骨应力和应变、接触压力及载荷分布。
完整膝关节模型中的载荷分布、接触压力和接触面积得到验证。在UKA模型中，当胫骨托外翻倾斜>4°时，近端内侧皮质骨的von Mises应力和压缩应变显著增加，这可能会增加残留疼痛的风险。当内翻倾斜>4°时，胫骨龙骨槽处的压缩应变高于高阈值，这可能会导致假体移位的风险增加。无论倾斜角度如何，胫骨骨切除角都是应变增加部位。切除表面的压缩应变随倾斜度的变化略有改变，预计不会引起骨吸收和假体松动。外侧间室的接触压力和载荷百分比随内翻倾斜度增加而增加，这可能会导致骨关节炎进展。
UKA术后的静态膝关节生物力学可受到胫骨假体冠状面排列的显著影响。在活动平台UKA中，可推荐胫骨假体倾斜角度范围为外翻4°至内翻4°。
Zotero 插件
