Department of Orthopaedic Surgery, Bioengineering Laboratory, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, GRJ 1215, Boston, MA 02114, USA.
Int Orthop. 2010 Apr;34(4):497-503. doi: 10.1007/s00264-009-0777-2. Epub 2009 Apr 22.
The objective of this study was to investigate biomechanics of TKA patients during high flexion. Six patients (seven knees) with a posterior-substituting TKA and weight-bearing flexion >130 degrees were included in the study. The six degree-of-freedom kinematics, tibiofemoral contact, and cam-post contact were measured during a deep knee bend using dual-plane fluoroscopy. The patients achieved average weight-bearing flexion of 139.5 +/- 4.5 degrees. Posterior femoral translation and internal tibial rotation increased steadily beyond 90 degrees flexion, and a sharp increase in varus rotation was noted at maximum flexion. Initial cam-post engagement was observed at 100.3 +/- 6.7 degrees flexion. Five knees had cam-post disengagement before maximum flexion. Lateral femoral condylar lift-off was found in five out of seven knees at maximum flexion, and medial condylar lift-off was found in one knee. Future studies should investigate if the kinematic characteristics of posterior-substituting TKA knees noted in this study are causative factors of high knee flexion.
本研究旨在探讨高屈曲度下 TKA 患者的生物力学情况。研究纳入了 6 名（7 膝）采用后稳定型 TKA 且膝关节负重屈曲度＞130 度的患者。使用双平面透视技术，在深度屈膝时测量了 6 自由度运动学、胫股接触和凸轮-销接触情况。患者平均达到了 139.5±4.5 度的负重屈曲度。在超过 90 度屈曲时，股骨后移和胫骨内旋逐渐增加，在最大屈曲时出现明显的内翻旋转增加。初始凸轮-销接触发生在 100.3±6.7 度屈曲时。5 个膝关节在最大屈曲前出现凸轮-销脱离。在最大屈曲时，7 个膝关节中有 5 个外侧股骨髁有抬起，1 个膝关节有内侧股骨髁抬起。未来的研究应探讨本研究中观察到的后稳定型 TKA 膝关节的运动学特征是否是高膝关节屈曲度的致病因素。
