Li Zhan-Chun, Dai Li-Yang, Jiang Lei-Sheng, Qiu Shijing
Xinhua Hospital, Renji Hospital, and Shanghai Jiaotong University School of Medicine, Shanghai, China.
Arthritis Rheum. 2012 Dec;64(12):3955-62. doi: 10.1002/art.34670.
Osteoarthritis (OA) and osteoporosis (OP) of the hip rarely occur in the same patient. The purpose of this study was to determine whether this difference might be attributable to the different quantity and quality of subchondral cancellous bone in the two conditions.
Subchondral cancellous bone from the femoral head was obtained at the time of hip arthroplasty from 60 postmenopausal women, 30 with OA and 30 with OP. In each group, 10 specimens were subjected to compressive fatigue loading and 20 were left nonloaded. Specimens were examined by compressive mechanical testing, micro-computed tomography scanning, fluorescence microscopy, and nanoindentation techniques.
Both the ultimate stress and the elastic modulus of cancellous bone from OA patients were significantly higher than those of cancellous bone from OP patients (P < 0.05). Compared to cancellous bone from OP patients, the bone volume fraction and trabecular thickness were significantly increased, but bone matrix mineralization was significantly decreased, in cancellous bone from OA patients (P < 0.05 for each comparison). The microcrack density was significantly higher in OP cancellous bone than in OA cancellous bone (P < 0.001), irrespective of fatigue loading. In addition, fatigue loading resulted in a significant increase in microcrack density in both OA and OP cancellous bone (P < 0.001). There was no significant difference in nanoindentation elastic modulus and hardness between cancellous bone from OA and OP patients, as well as between bones with and without fatigue loading.
The difference in mechanical properties between OA and OP cancellous bone is attributed to different bone mass and bone structure. OP cancellous bone is susceptible to fatigue damage due to insufficient structure. However, increased bone volume and plate-like structure provide OA cancellous bone a superior capacity to resist fatigue damage.
髋关节骨关节炎（OA）和骨质疏松症（OP）很少在同一患者中出现。本研究的目的是确定这种差异是否可能归因于这两种情况下软骨下松质骨的数量和质量不同。
在髋关节置换术时从60名绝经后女性获取股骨头的软骨下松质骨，其中30名患有OA，30名患有OP。每组中，10个标本进行压缩疲劳加载，20个不加载。通过压缩力学测试、显微计算机断层扫描、荧光显微镜检查和纳米压痕技术对标本进行检查。
OA患者的松质骨的极限应力和弹性模量均显著高于OP患者的松质骨（P < 0.05）。与OP患者的松质骨相比，OA患者的松质骨的骨体积分数和小梁厚度显著增加，但骨基质矿化显著降低（每次比较P < 0.05）。无论是否进行疲劳加载，OP松质骨中的微裂纹密度均显著高于OA松质骨（P < 0.001）。此外，疲劳加载导致OA和OP松质骨中的微裂纹密度均显著增加（P < 0.001）。OA和OP患者的松质骨之间，以及有和没有疲劳加载的骨之间，纳米压痕弹性模量和硬度没有显著差异。
OA和OP松质骨的力学性能差异归因于不同的骨量和骨结构。OP松质骨由于结构不足而易受疲劳损伤。然而，增加的骨体积和板状结构使OA松质骨具有更强的抗疲劳损伤能力。
