Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.
Knee Surg Sports Traumatol Arthrosc. 2012 Oct;20(10):2002-10. doi: 10.1007/s00167-011-1796-2. Epub 2011 Nov 29.
The Journey bicruciate substituting (BCS) TKR was designed to restore normal knee kinematics. It has two cam-post mechanisms which substitute for the ACL and PCL. The aim of this study was to undertake a comprehensive study of the Journey BCS kinematics in vivo to assess the function of the cam-post mechanisms and their effect on functional kinematics and compared to the kinematics of a group of normal knees.
The kinematics of 10 Journey BCS were assessed fluoroscopically during step-up and lunge exercises, and were compared to those of 20 normal knees. The fluoroscopic images were used to determine relative implant orientation using a 2D to 3D reconstruction method. The determined relative tibio-femoral orientations allowed for cam-post engagement and tibio-femoral contact points to be determined. Functional kinematics were assessed using the patella tendon angle (PTA) and the patella flexion angle (PFA) relationship with the knee flexion angle (KFA).
The average maximum flexion achieved by the Journey was 124.7°. Both cam mechanisms engaged: The anterior cam during extension at 12.6° and the posterior cam in flexion at 45.4°. During flexion, the contacts points on the tibia moved posteriorly with no paradoxical anterior translation. The PTA/KFA relationships of the Journey implant group for both the step-up and lunge exercises were broadly similar in terms of trend to those established for the normal knee but the PTA between 10° KFA and 140° KFA were significantly (P < 0.05) lower than that for the normal knees. The PFA/KFA trend for both the implant and normal groups showed a linear relationship; however, the values of PFA were higher for the Journey compared to the normal.
The Journey BCS showed no paradoxical anterior movement and sufficient posterior femoral roll back which corresponded with the engagement of the anterior and posterior cam-post mechanisms. Trends shown by the PTA/KFA and PFA/KFA kinematic profiles observed for the Journey group were more normal than those seen with other designs of TKR. However, despite being more close to normal than other implants, the Journey group showed a different kinematic profile to that of the normal knees, which is most likely due to the femur being too far posterior relative to the tibia.
Case-control study, retrospective, comparative study, Level III.
Journey 双交叉替代（BCS）TKR 的设计目的是恢复正常的膝关节运动学。它有两个凸轮-柱机制，可替代 ACL 和 PCL。本研究的目的是对 Journey BCS 的体内运动学进行全面研究，以评估凸轮-柱机制的功能及其对功能性运动学的影响，并与一组正常膝关节的运动学进行比较。
在台阶上升和弓步运动中，通过荧光透视评估 10 个 Journey BCS 的运动学，并与 20 个正常膝关节进行比较。荧光透视图像用于通过二维到三维重建方法确定相对植入物的方向。确定的相对胫股取向允许凸轮-柱的接合以及胫股接触点的确定。功能性运动学通过髌腱角（PTA）和髌股屈曲角（PFA）与膝关节屈曲角（KFA）的关系来评估。
Journey 达到的平均最大屈曲度为 124.7°。两个凸轮机制都参与了运动：在伸展时，前凸轮在 12.6°处接合，后凸轮在屈曲时在 45.4°处接合。在屈曲过程中，胫骨上的接触点向后移动，没有反常的前向平移。在台阶上升和弓步运动中，Journey 植入组的 PTA/KFA 关系在趋势上与正常膝关节建立的关系相似，但在 10°KFA 和 140°KFA 之间的 PTA 明显（P <0.05）低于正常膝关节。植入组和正常组的 PFA/KFA 趋势均呈线性关系；然而，Journey 的 PFA 值高于正常膝关节。
Journey BCS 没有出现反常的前向运动，并且股骨后滚充分，这与前凸轮-柱和后凸轮-柱机制的接合相对应。在 Journey 组观察到的 PTA/KFA 和 PFA/KFA 运动学曲线的趋势比其他 TKR 设计更正常。然而，尽管与其他植入物相比更接近正常，但 Journey 组与正常膝关节的运动学曲线不同，这很可能是由于股骨相对于胫骨太靠后。
病例对照研究，回顾性，比较研究，III 级。
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