Zysset P K, Sonny M, Hayes W C
Department of Orthopaedic Surgery, Charles A. Dana Research Institute, Beth Israel Hospital, Boston, Massachusetts.
J Arthroplasty. 1994 Apr;9(2):203-16. doi: 10.1016/0883-5403(94)90070-1.
Alteration of morphologic and mechanical properties of trabecular bone in the osteoarthritic proximal tibia may be a contributing factor in tibial component loosening. To explore this issue, the authors performed tissue property measurements, morphologic analysis, and mechanical testing of subchondral, epiphyseal, and metaphyseal trabecular bone specimens retrieved from six human proximal tibias exhibiting a range of medial unicondylar osteoarthritic degeneration. Apparent density in the proximal tibia was altered according to varus misalignment and medial subluxation associated with medial osteoarthritis of the knee. In subchondral bone, a decrease in tissue mineralization contributed to a significant reduction in axial mechanical properties with degenerative disease (P < .0005). In epiphyseal and metaphyseal bone, trabecular thickness and the number of trabeculae increased linearly with volume fraction, providing a power law relationship between axial elastic modulus and apparent density (R2 = .84). Average elastic properties of the tibial epiphysis and metaphysis were not reduced by degenerative disease (P < .05). The results suggest that absolute minimization of tibial resection might not be an optimal strategy for tibial component fixation and that mechanical properties of the tibial resection surface are more homogeneous in planes parallel to the joint surface than in a plane normal to the longitudinal axis of the tibia.
骨关节炎患者胫骨近端小梁骨的形态学和力学性能改变可能是胫骨假体松动的一个促成因素。为探讨这一问题，作者对取自6例表现出不同程度内侧单髁骨关节炎退变的人类胫骨近端的软骨下、骨骺和干骺端小梁骨标本进行了组织性能测量、形态学分析和力学测试。胫骨近端的表观密度根据与膝关节内侧骨关节炎相关的内翻畸形和内侧半脱位而改变。在软骨下骨，随着退行性疾病的发展，组织矿化减少导致轴向力学性能显著降低（P < .0005）。在骨骺和干骺端骨中，小梁厚度和小梁数量随体积分数呈线性增加，在轴向弹性模量和表观密度之间呈现幂律关系（R2 = .84）。退行性疾病并未降低胫骨骨骺和干骺端的平均弹性性能（P < .05）。结果表明，将胫骨切除绝对最小化可能不是胫骨假体固定的最佳策略，并且胫骨切除表面在平行于关节面的平面上的力学性能比在垂直于胫骨纵轴的平面上更均匀。
