Department of Orthopaedics, Orthopaedic Research Laboratories, University of Pittsburgh, Rivertech Office Works, 3820 South Water Street, Pittsburgh, PA 15203, USA.
J Biomech. 2010 Mar 22;43(5):994-7. doi: 10.1016/j.jbiomech.2009.11.014. Epub 2009 Dec 14.
A new technique is presented that utilizes relative velocity vectors between articulating surfaces to characterize internal/external rotation of the tibio-femoral joint during dynamic loading. Precise tibio-femoral motion was determined by tracking the movement of implanted tantalum beads in high-speed biplane X-rays. Three-dimensional, subject-specific CT reconstructions of the femur and tibia, consisting of triangular mesh elements, were positioned in each analyzed frame. The minimum distance between subchondral bone surfaces was recorded for each mesh element comprising each bone surface, and the relative velocity between these opposing closest surface elements was determined in each frame. Internal/external rotation was visualized by superimposing tangential relative velocity vectors onto bone surfaces at each instant. Rotation about medial and lateral compartments was quantified by calculating the angle between these tangential relative vectors within each compartment. Results acquired from 68 test sessions involving 23 dogs indicated a consistent pattern of sequential rotation about the lateral condyle (approximately 60 ms after paw strike) followed by rotation about the medial condyle (approximately 100 ms after paw strike). These results imply that axial knee rotation follows a repeatable pattern within and among subjects. This pattern involves rotation about both the lateral and medial compartments. The technique described can be easily applied to study human knee internal/external rotation during a variety of activities. This information may be useful to define normal and pathologic conditions, to confirm post-surgical restoration of knee mechanics, and to design more realistic prosthetic devices. Furthermore, analysis of joint arthrokinematics, such as those described, may identify changes in joint mechanics associated with joint degeneration.
提出了一种新的技术，该技术利用关节表面之间的相对速度矢量来描述动态加载过程中胫股关节的内/外旋转。通过在高速双平面 X 射线下跟踪植入钽珠的运动，精确确定了胫股运动。对股骨和胫骨进行了基于 CT 的三维个体化重建，重建结构由三角形网格元素组成，并在每个分析帧中对其进行定位。记录了每个网格元素（包含每个骨表面）中近软骨表面之间的最小距离，并且在每个帧中确定了这些相对近表面元素之间的相对速度。通过在每个瞬间将切向相对速度矢量叠加到骨表面上，可视化了内/外旋转。通过计算每个间隔内这些切向相对矢量之间的角度，量化了内侧和外侧间隔的旋转。对涉及 23 只狗的 68 次测试结果表明，外侧髁（在足触地后约 60ms）之后，连续出现外侧髁的旋转，随后是内侧髁的旋转（在足触地后约 100ms）。这些结果表明，轴向膝关节旋转在个体内和个体间遵循可重复的模式。这种模式涉及到外侧和内侧间隔的旋转。所描述的技术可以很容易地应用于研究各种活动中人类膝关节的内/外旋转。这些信息可能有助于定义正常和病理状态，确认膝关节手术后的力学恢复，并设计更逼真的假体设备。此外，关节运动学的分析，如所述，可以确定与关节退化相关的关节力学变化。
