Department of Orthopaedic Surgery, Duke University, Durham, NC, United States.
Department of Orthopaedic Surgery, Duke University, Durham, NC, United States; Department of Biomedical Engineering, Duke University, Durham, NC, United States.
J Biomech. 2022 Mar;134:110991. doi: 10.1016/j.jbiomech.2022.110991. Epub 2022 Feb 7.
Obesity is a primary risk factor for osteoarthritis. While previous work has addressed relationships between in vivo cartilage mechanics, composition, and obesity in the tibiofemoral joint, there is limited information on these relationships in the patellofemoral joint. The purpose of this study was to compare the patellofemoral cartilage mechanical response to walking in participants with normal and obese body mass indices (BMIs). Additionally, patellar cartilage T1rho relaxation times were measured before exercise to characterize the biochemical composition of the tissue. Fifteen participants (eight with normal BMI and seven with obese BMI) underwent baseline magnetic resonance imaging (MRI) of their right knee. They then walked on a treadmill for 20 min at a speed normalized to their leg length before a second MRI scan. Subsequently, three-dimensional models of the bones and articular surfaces of the patellofemoral joint were created via manual segmentation of the pre- and post-exercise MR images to compute cartilage thickness and strain. Strain was defined as the change in patellofemoral cartilage thickness normalized to the baseline thickness. Results showed that participants with an obese BMI exhibited significantly increased patellofemoral cartilage strain compared to those with a normal BMI (5.4 ± 4% vs. 1.7 ± 3%, respectively; p = 0.003). Furthermore, patellar cartilage T1rho values were significantly higher in participants with obese versus normal BMIs (95 ms vs. 83 ms, respectively; p = 0.049), indicative of decreased proteoglycan content in those with an obese BMI. In summary, the altered patellofemoral cartilage strain and composition observed in those with an obese BMI may be indicative of cartilage degeneration.
肥胖是骨关节炎的一个主要危险因素。虽然之前的工作已经研究了活体软骨力学、组成和肥胖与胫股关节之间的关系，但关于髌股关节中这些关系的信息有限。本研究的目的是比较正常和肥胖体重指数（BMI）参与者在行走时髌股软骨的机械反应。此外，还测量了髌股软骨 T1rho 弛豫时间，以表征组织的生化组成。15 名参与者（8 名正常 BMI 和 7 名肥胖 BMI）接受了右膝基线磁共振成像（MRI）检查。然后，他们在跑步机上以与腿长标准化的速度行走 20 分钟，然后进行第二次 MRI 扫描。随后，通过手动分割运动前后的 MRI 图像，创建了髌股关节的骨骼和关节表面的三维模型，以计算软骨厚度和应变。应变定义为髌股软骨厚度相对于基线厚度的变化。结果表明，肥胖 BMI 的参与者的髌股软骨应变明显高于正常 BMI 的参与者（分别为 5.4±4%和 1.7±3%；p=0.003）。此外，肥胖 BMI 的参与者的髌软骨 T1rho 值明显高于正常 BMI 的参与者（分别为 95ms 和 83ms；p=0.049），表明肥胖 BMI 的参与者的软骨中蛋白聚糖含量减少。总之，肥胖 BMI 参与者观察到的髌股软骨应变和组成的改变可能表明软骨退化。
