Foot and Ankle Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
Ultrasound medicine department, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
BMC Musculoskelet Disord. 2023 Sep 28;24(1):767. doi: 10.1186/s12891-023-06882-0.
To investigate the differences of patellofemoral joint pressure and contact area between the process of stair ascent and stair descent.
The finite element models of 9 volunteers without disorders of knee (9 males) to estimate patellar cartilage pressure during the stair ascent and the stair descent. Simulations took into account cartilage morphology from magnetic resonance imaging, joint posture from weight-bearing magnetic resonance imaging, and ligament model. The three-dimension models of the patella, femur and tibia were developed with the medical image processing software, Mimics 11.1. The ligament was established by truss element of the non-linear FE solver. The equivalent gravity direction (-z direction) load was applied to the whole end of femur (femoral head) according to the body weight of the volunteers, and the force of patella was observed. A paired-samples t-test or Wilcoxon rank sum test to make comparisons between stair ascent and stair descent. Statistical analyses were performed using SPSS 22.0 using a P value of 0.05 to indicate significance.
During the stair descent (knee flexion at 30°), the contact pressure of the patella was 2.59 ± 0.06Mpa. The contact pressure of femoral trochlea cartilage was 2.57 ± 0.06Mpa. During the stair ascent (knee flexion at 60°), the contact pressure with patellar cartilage was 2.82 ± 0.08Mpa. The contact pressure of the femoral trochlea cartilage was 3.03 ± 0.11Mpa. The contact area between patellar cartilage and femoral trochlea cartilage was 249.27 ± 1.35mm during the stair descent, which was less than 434.32 ± 1.70mm during the stair ascent. The area of high pressure was located in the lateral area of patella during stair descent and the area of high pressure was scattered during stair ascent.
There are small change in the cartilage contact pressure between stair ascent and stair descent, indicating that the joint adjusts the contact pressure by increasing the contact area.
研究上楼梯和下楼梯过程中髌股关节压力和接触面积的差异。
对 9 名无膝关节疾病志愿者（9 名男性）的有限元模型进行估计，以评估上楼梯和下楼梯过程中髌骨关节软骨的压力。模拟考虑了磁共振成像的软骨形态、负重磁共振成像的关节姿势以及韧带模型。使用医学图像处理软件 Mimics 11.1 开发了髌骨、股骨和胫骨的三维模型。通过非线性有限元求解器的桁架元素建立了韧带。根据志愿者的体重，将等效重力方向（-z 方向）载荷施加到整个股骨（股骨头）末端，并观察髌骨的受力情况。采用配对样本 t 检验或 Wilcoxon 秩和检验对上楼梯和下楼梯进行比较。采用 SPSS 22.0 进行统计分析，P 值<0.05 表示差异具有统计学意义。
在下楼梯（膝关节屈曲 30°）时，髌骨的接触压力为 2.59±0.06Mpa。股骨滑车软骨的接触压力为 2.57±0.06Mpa。在上楼梯（膝关节屈曲 60°）时，髌骨软骨的接触压力为 2.82±0.08Mpa。股骨滑车软骨的接触压力为 3.03±0.11Mpa。下楼梯时髌骨软骨与股骨滑车软骨的接触面积为 249.27±1.35mm，而上楼梯时为 434.32±1.70mm。下楼梯时，髌骨的高压区位于外侧，而上楼梯时高压区分散。
上楼梯和下楼梯时软骨接触压力变化较小，表明关节通过增加接触面积来调节接触压力。
