Ali Azhar A, Mannen Erin M, Rullkoetter Paul J, Shelburne Kevin B
Center for Orthopaedic Biomechanics, University of Denver, 2155 East Wesley Avenue, 80208, Denver, Colorado.
J Orthop Res. 2018 Jul;36(7):1910-1918. doi: 10.1002/jor.23865. Epub 2018 Mar 6.
Successful outcome following total knee arthroplasty (TKA) with patella resurfacing is partly determined by the restoration of patellofemoral (PF) function and recovery of the quadriceps mechanism. The current study compared two patellar TKA geometries (medialized dome and anatomic) to determine their impact on PF mechanics and quadriceps function. In-vivo, subject-specific patellar mechanics were evaluated using a sequential experimental and modeling approach. First, stereo radiography, marker-based motion capture, and force plate data were collected for TKA patients (10 dome, 10 anatomic) performing a knee extension and lunge. Second, subject-specific, whole-body, musculoskeletal models, including 6 degrees-of-freedom (DOF) knee joint kinematics, were created for each subject and activity to predict quadriceps forces. Last, finite element models of each subject and activity were created to predict PF kinematics, patellar loading, moment arm, and patellar tendon angle. Differences in mechanics between dome and anatomic patients were highlighted during load-bearing (lunge) activity. Anatomic subjects demonstrated greater PF flexion angles (avg. 11 ± 3°) compared to dome subjects during lunge. Similar to the natural knee, contact locations on the patella migrated inferior to superior as the knee flexed in anatomic subjects, but remained relatively superior in dome subjects. Differences in kinematics and contact location likely contributed to altered mechanics with anatomic subjects presenting greater load transfer from the quadriceps to the patellar tendon in deep flexion (>75°), and dome subjects demonstrating larger contact forces during lunge. Although there was substantial patient variability, evaluations of PF mechanics suggested improved quadriceps function and more natural kinematics in the anatomic design. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1910-1918, 2018.
全膝关节置换术（TKA）联合髌骨表面置换术后的成功结果部分取决于髌股（PF）功能的恢复和股四头肌机制的恢复。本研究比较了两种髌骨TKA几何形状（内侧化穹顶型和解剖型），以确定它们对PF力学和股四头肌功能的影响。采用序贯实验和建模方法对体内特定受试者的髌骨力学进行评估。首先，收集了TKA患者（10例穹顶型、10例解剖型）进行膝关节伸展和弓步动作时的立体放射摄影、基于标记的运动捕捉和测力板数据。其次，为每个受试者和活动创建特定受试者的全身肌肉骨骼模型，包括6自由度（DOF）膝关节运动学，以预测股四头肌力量。最后，为每个受试者和活动创建有限元模型，以预测PF运动学、髌骨负荷、力臂和髌腱角度。在负重（弓步）活动期间，穹顶型和解剖型患者之间的力学差异得到凸显。在弓步动作中，解剖型受试者的PF屈曲角度（平均11±3°）比穹顶型受试者更大。与自然膝关节相似，在解剖型受试者中，随着膝关节屈曲，髌骨上的接触位置从下向上移动，但在穹顶型受试者中保持相对较高位置。运动学和接触位置的差异可能导致力学改变，解剖型受试者在深度屈曲（>75°）时从股四头肌向髌腱的负荷转移更大，而穹顶型受试者在弓步动作时表现出更大的接触力。尽管患者个体差异很大，但对PF力学的评估表明，解剖型设计中股四头肌功能得到改善，运动学更自然。©2018骨科研究学会。由Wiley Periodicals, Inc.出版。《矫形外科研究杂志》36:1910 - 1918, 2018。
