Department of Orthopaedic Surgery, Duke University, Box 3093, Duke University Medical Center, Durham, NC, 27710, USA.
Department of Biomedical Engineering, Duke University, Campus Box 90281, 101 Science Drive, Durham, 27708, NC, USA.
Arthritis Res Ther. 2018 Oct 17;20(1):232. doi: 10.1186/s13075-018-1727-4.
Obesity is a primary risk factor for the development of knee osteoarthritis (OA). However, there remains a lack of in vivo data on the influence of obesity on knee cartilage mechanics and composition. The purpose of this study was to determine the relationship between obesity and tibiofemoral cartilage properties.
Magnetic resonance images (3T) of cartilage geometry (double-echo steady-state) and T1rho relaxation of the knee were obtained in healthy subjects with a normal (n = 8) or high (n = 7) body mass index (BMI) before and immediately after treadmill walking. Subjects had no history of lower limb injury or surgery. Bone and cartilage surfaces were segmented and three-dimensional models were created to measure cartilage thickness and strain. T1rho relaxation times were measured before exercise in both the tibial and femoral cartilage in order to characterize biochemical composition. Body fat composition was also measured.
Subjects with a high BMI exhibited significantly increased tibiofemoral cartilage strain and T1rho relaxation times (P <0.05). Tibial pre-exercise cartilage thickness was also affected by BMI (P <0.05). Correlational analyses revealed that pre-exercise tibial cartilage thickness decreased with increasing BMI (R = 0.43, P <0.01) and body fat percentage (R = 0.58, P <0.01). Tibial and femoral cartilage strain increased with increasing BMI (R = 0.45, P <0.01; R = 0.51, P <0.01, respectively) and increasing body fat percentage (R = 0.40, P <0.05; R = 0.38, P <0.05, respectively). Additionally, tibial T1rho was positively correlated with BMI (R = 0.39, P <0.05) and body fat percentage (R = 0.47, P <0.01).
Strains and T1rho relaxation times in the tibiofemoral cartilage were increased in high BMI subjects compared with normal BMI subjects. Additionally, pre-exercise tibial cartilage thickness decreased with obesity. Reduced proteoglycan content may be indicative of pre-symptomatic osteoarthritic degeneration, resulting in reduced cartilage thickness and increased deformation of cartilage in response to loading.
肥胖是膝关节骨关节炎（OA）发展的主要危险因素。然而，目前还缺乏肥胖对膝关节软骨力学和成分影响的体内数据。本研究旨在确定肥胖与胫骨股骨软骨特性之间的关系。
在健康受试者中，使用正常（n=8）或高（n=7）体质量指数（BMI）的磁共振成像（3T）获得软骨几何形状（双回波稳态）和膝关节 T1rho 弛豫。受试者无下肢损伤或手术史。对骨和软骨表面进行分割，并创建三维模型以测量软骨厚度和应变。在运动前测量胫骨和股骨软骨中的 T1rho 弛豫时间，以表征生化组成。还测量了体脂肪成分。
高 BMI 受试者的胫骨股骨软骨应变和 T1rho 弛豫时间显著增加（P<0.05）。BMI 也影响胫骨预运动软骨厚度（P<0.05）。相关分析显示，胫骨预运动软骨厚度随 BMI 增加而减少（R=0.43，P<0.01）和体脂肪百分比增加（R=0.58，P<0.01）。胫骨和股骨软骨应变随 BMI 增加而增加（R=0.45，P<0.01；R=0.51，P<0.01）和体脂肪百分比增加（R=0.40，P<0.05；R=0.38，P<0.05）。此外，胫骨 T1rho 与 BMI 呈正相关（R=0.39，P<0.05）和体脂肪百分比（R=0.47，P<0.01）。
与正常 BMI 受试者相比，高 BMI 受试者的胫骨股骨软骨应变和 T1rho 弛豫时间增加。此外，肥胖时胫骨预运动软骨厚度减少。蛋白聚糖含量减少可能预示着亚临床骨关节炎退变，导致软骨厚度减少，软骨在负荷作用下变形增加。
Zotero 插件
