Pejhan Shabnam, Bohm Eric, Brandt Jan-Mels, Gascoyne Trevor, Wyss Urs
Department of Mechanical Engineering, University of Manitoba, Engineering & Information Technology Complex, 75 A Chancellors Circle, Winnipeg, Manitoba, Canada.
Orthopaedic Innovation Centre, 1155 Concordia Ave., Winnipeg, Manitoba, Canada; Department of Surgery, Section of Orthopedic Surgery, University of Manitoba, 820 Sherbrook Street, Winnipeg, Manitoba, Canada.
Med Eng Phys. 2017 Oct;48:168-175. doi: 10.1016/j.medengphy.2017.06.018. Epub 2017 Jul 6.
Different designs of total knee replacements (TKRs) aim to enhance the satisfaction of the patients by providing close to normal kinematics. In the surface-guided TKRs, the guidance of the motion in a normal pattern should be achieved through specially shaped articulating geometries. This study used virtual simulation along with a load-controlled knee wear simulator to evaluate the kinematic performance of a customized surface-guided TKR under weight-bearing conditions of lunging and squatting activities. The outcome pattern of TKR motion almost agreed with the predefined design target. The tibial insert rotated internally through a maximum angle of 10.6° and 19.94° for the experimentally simulated lunging and squatting cycles, respectively. This rotation occurred around a medial center, as indicated by a small amount of posterior translation of the medial condyle (maximum of 2.5mm and 6.4mm for lunging and squatting) versus the posterior translation of the lateral condyle (maximum of 12mm and 24.2mm for lunging and squatting). The contact forces mainly provided the guidance of the motion at the tibiofemoral articulating surfaces.The normalized root mean square error between outcomes of the virtual simulations and tests for the angle of internal-external rotation of the tibial insert was less than 8% for one cycle of lunging and squatting. These measures confirm the validity of the virtual simulation for future evaluations of the customized surface-guided TKRs.
不同设计的全膝关节置换术（TKRs）旨在通过提供接近正常的运动学来提高患者满意度。在表面引导式全膝关节置换术中，应通过特殊形状的关节几何结构实现正常模式下的运动引导。本研究使用虚拟模拟以及负载控制的膝关节磨损模拟器，在弓步和下蹲活动的负重条件下评估定制表面引导式全膝关节置换术的运动学性能。全膝关节置换术运动的结果模式几乎与预定义的设计目标一致。在实验模拟的弓步和下蹲周期中，胫骨假体分别向内旋转最大角度为10.6°和19.94°。这种旋转围绕内侧中心发生，如内侧髁的少量后移所示（弓步和下蹲时最大分别为2.5mm和6.4mm），相对于外侧髁的后移（弓步和下蹲时最大分别为12mm和24.2mm）。接触力主要在胫股关节表面提供运动引导。在弓步和下蹲的一个周期内，胫骨假体内外旋转角度的虚拟模拟结果与测试结果之间的归一化均方根误差小于8%。这些测量结果证实了虚拟模拟对于未来定制表面引导式全膝关节置换术评估的有效性。
