Department of Physical Therapy, University of Pittsburgh, PA, USA.
Osteoarthritis Cartilage. 2011 Mar;19(3):287-94. doi: 10.1016/j.joca.2010.12.001. Epub 2010 Dec 21.
To test the hypothesis that individuals with patellofemoral pain (PFP) exhibit greater patellofemoral joint stress profiles compared to persons who are pain-free.
Ten females with PFP and ten gender, age, and activity-matched pain-free controls participated. Patella and femur stress profiles were quantified utilizing subject-specific finite element (FE) models of the patellofemoral joint at 15° and 45° of knee flexion. Input parameters for the FE model included: (1) joint geometry, (2) quadriceps muscle forces, and (3) weight-bearing patellofemoral joint kinematics. Using a nonlinear FE solver, quasi-static loading simulations were performed to quantify each subject's patellofemoral joint stress profile during a static squatting maneuver. The patella and femur peak and mean hydrostatic pressure as well as the peak and mean octahedral shear stress for the elements representing the chondro-osseous interface were quantified.
Compared to the pain-free controls, individuals with PFP consistently exhibited greater peak and mean hydrostatic pressure as well as peak and mean octahedral shear stress for the elements representing the patella and femur chondro-osseous interface across the two knee flexion angles tested (15° and 45°).
The combined finding of elevated hydrostatic pressure and octahedral shear stress across the two knee flexion angles supports the premise that PFP may be associated with elevated joint stress. Therefore, treatments aimed at decreasing patellofemoral joint stress may be indicated in this patient population.
验证假设，即髌股疼痛（PFP）患者的髌股关节压力分布与无疼痛患者存在差异。
共纳入 10 名女性 PFP 患者和 10 名性别、年龄和活动水平匹配的无痛对照组。利用髌股关节的个体特定有限元（FE）模型，在 15°和 45°膝关节屈曲时量化髌股关节的髌骨和股骨压力分布。FE 模型的输入参数包括：（1）关节几何形状，（2）股四头肌力，以及（3）负重髌股关节运动学。使用非线性 FE 求解器，进行准静态加载模拟，以量化每位受试者在静态蹲坐动作期间髌股关节的压力分布。量化了代表软骨-骨界面的元素的髌骨和股骨峰值和平均静水压力以及峰值和平均八面体剪切应力。
与无痛对照组相比，PFP 患者在两种膝关节屈曲角度（15°和 45°）下，代表髌骨和股骨软骨-骨界面的元素的峰值和平均静水压力以及峰值和平均八面体剪切应力均持续升高。
在两种膝关节屈曲角度下，静水压力和八面体剪切应力升高的综合发现支持了这样的前提，即 PFP 可能与关节压力升高有关。因此，针对降低髌股关节压力的治疗可能适用于该患者群体。
