Jung Yihwan, Phan Cong-Bo, Koo Seungbum
J Biomech Eng. 2016 Feb;138(2):021016. doi: 10.1115/1.4032414.
Joint contact forces measured with instrumented knee implants have not only revealed general patterns of joint loading but also showed individual variations that could be due to differences in anatomy and joint kinematics. Musculoskeletal human models for dynamic simulation have been utilized to understand body kinetics including joint moments, muscle tension, and knee contact forces. The objectives of this study were to develop a knee contact model which can predict knee contact forces using an inverse dynamics-based optimization solver and to investigate the effect of joint constraints on knee contact force prediction. A knee contact model was developed to include 32 reaction force elements on the surface of a tibial insert of a total knee replacement (TKR), which was embedded in a full-body musculoskeletal model. Various external measurements including motion data and external force data during walking trials of a subject with an instrumented knee implant were provided from the Sixth Grand Challenge Competition to Predict in vivo Knee Loads. Knee contact forces in the medial and lateral portions of the instrumented knee implant were also provided for the same walking trials. A knee contact model with a hinge joint and normal alignment could predict knee contact forces with root mean square errors (RMSEs) of 165 N and 288 N for the medial and lateral portions of the knee, respectively, and coefficients of determination (R2) of 0.70 and -0.63. When the degrees-of-freedom (DOF) of the knee and locations of leg markers were adjusted to account for the valgus lower-limb alignment of the subject, RMSE values improved to 144 N and 179 N, and R2 values improved to 0.77 and 0.37, respectively. The proposed knee contact model with subject-specific joint model could predict in vivo knee contact forces with reasonable accuracy. This model may contribute to the development and improvement of knee arthroplasty.
通过仪器化膝关节植入物测量的关节接触力不仅揭示了关节负荷的一般模式，还显示了个体差异，这些差异可能是由于解剖结构和关节运动学的不同所致。用于动态模拟的肌肉骨骼人体模型已被用于理解身体动力学，包括关节力矩、肌肉张力和膝关节接触力。本研究的目的是开发一种膝关节接触模型，该模型可以使用基于逆动力学的优化求解器预测膝关节接触力，并研究关节约束对膝关节接触力预测的影响。开发了一种膝关节接触模型，该模型在全膝关节置换（TKR）胫骨假体表面包含32个反作用力元素，并嵌入全身肌肉骨骼模型中。第六届预测体内膝关节负荷大挑战竞赛提供了一名佩戴仪器化膝关节植入物受试者行走试验期间的各种外部测量数据，包括运动数据和外力数据。同一行走试验还提供了仪器化膝关节植入物内侧和外侧部分的膝关节接触力。具有铰链关节和正常对线的膝关节接触模型可以预测膝关节内侧和外侧部分的膝关节接触力，其均方根误差（RMSE）分别为165 N和288 N，决定系数（R2）分别为0.70和-0.63。当调整膝关节的自由度（DOF）和腿部标记的位置以考虑受试者下肢外翻对线时，RMSE值分别提高到144 N和179 N，R2值分别提高到0.77和0.37。所提出的具有受试者特异性关节模型的膝关节接触模型可以合理准确地预测体内膝关节接触力。该模型可能有助于膝关节置换术的发展和改进。
