Anglin Carolyn, Ho Karen C T, Briard Jean-Louis, de Lambilly Charles, Plaskos Christopher, Nodwell Eric, Stindel Eric
Centre for Bioengineering Research & Education and Department of Civil Engineering, University of Calgary, Calgary, Alberta, Canada.
Comput Aided Surg. 2008 Nov;13(6):377-91. doi: 10.3109/10929080802594563.
Patellar maltracking after total knee arthroplasty often results in complications, including anterior knee pain, instability and impingement, and is therefore better resolved intraoperatively. Many factors can affect patellar kinematics during knee replacement, including component position, implant design, joint alignment, and soft tissue tensions. However, to our knowledge, the impact of arthroplasty on patellar kinematics has not been previously reported in vivo. A computer-assisted surgery (CAS) system was developed to measure the pre-arthroplasty patellar kinematics, display the distance between this path and the surface of the planned femoral component, and compare the post-arthroplasty path to the pre-arthroplasty path. Three surgeons from three centers used this CAS system to measure the in vivo pre- and post-arthroplasty kinematics of 18 patients. There was a small, but consistent, proximal shift in the tibial joint lines (mean: 4.2 mm), resulting in pseudo patella-baja, i.e., relatively more distal contact of the patella on the femoral component. This led to significant changes in proximodistal and anteroposterior patellar positioning as well as patellar flexion following arthroplasty (p < 0.008). Mediolateral shift, tilt and internal/external spin had the greatest magnitudes of change (mean: 4.1 mm, 4.6 degrees and 4.6 degrees, respectively) relative to their mean pre-arthroplasty ranges (averaging 2.1 mm, 5.8 degrees and 5.8 degrees, respectively); however, these changes were distributed almost equally medially and laterally, indicating no surgical bias in any one direction. Female patients had more lateral tilt on average than male patients throughout flexion (p < 0.004 post-arthroplasty, p < 0.03 pre-arthroplasty, in later flexion), as well as other kinematic differences; there may therefore be potential for improving overall kinematic results by focusing on gender differences during research, design and surgery. This study demonstrated the feasibility of using a CAS system to measure patellofemoral kinematics. Intraoperative awareness of patellar tracking, including knowledge of the tibiofemoral joint line, could have an impact on the surgical plan and thereby improve the postoperative outcome.
全膝关节置换术后髌股关节轨迹不良常导致并发症，包括膝关节前侧疼痛、不稳定和撞击，因此最好在术中解决。膝关节置换过程中，许多因素会影响髌股关节运动学，包括假体位置、植入物设计、关节对线和软组织张力。然而，据我们所知，关节置换术对髌股关节运动学的影响此前尚未有体内研究报道。我们开发了一种计算机辅助手术（CAS）系统，用于测量关节置换术前的髌股关节运动学，显示该轨迹与计划的股骨假体表面之间的距离，并将关节置换术后的轨迹与术前轨迹进行比较。来自三个中心的三位外科医生使用该CAS系统测量了18例患者关节置换术前和术后的体内运动学。胫骨关节线有一个小但一致的近端移位（平均：4.2毫米），导致假性髌骨低位，即髌骨在股骨假体上的接触相对更靠远端。这导致关节置换术后髌股关节在近远侧和前后方向的定位以及髌骨屈曲发生了显著变化（p < 0.008）。相对于术前平均范围（分别平均为2.1毫米、5.8度和5.8度），内外侧移位、倾斜和内/外旋转的变化幅度最大（分别平均为4.1毫米、4.6度和4.6度）；然而，这些变化在内外侧几乎平均分布，表明在任何一个方向上都没有手术偏向。女性患者在整个屈曲过程中平均比男性患者有更多的外侧倾斜（关节置换术后p < 0.004，术前后期屈曲时p < 0.03），以及其他运动学差异；因此，在研究、设计和手术过程中关注性别差异可能有改善整体运动学结果的潜力。本研究证明了使用CAS系统测量髌股关节运动学的可行性。术中了解髌股关节轨迹，包括胫股关节线的知识，可能会影响手术计划，从而改善术后结果。
