Rheumatology Research Unit, Instituto de Medicina Molecular, Lisbon, Portugal.
J Bone Miner Metab. 2012 Nov;30(6):692-9. doi: 10.1007/s00774-012-0370-4. Epub 2012 Aug 14.
Clinical risk factors (CRFs) are established predictors of fracture events. However, the influence of individual CRFs on trabecular mechanical fragility is still a subject of debate. In this study, we aimed to assess differences, adjusted for CRFs, between bone macrostructural parameters measured in ex-vivo specimens from hip fragility fracture patients and osteoarthritis patients, and to determine whether individual CRFs could predict trabecular bone mechanical behavior in hip fragility fractures. Additionally, we also looked for associations between the 10-year risk of major and hip fracture calculated by FRAX and trabecular bone mechanical performance. In this case-control study, a group of fragility fracture patients were compared with a group of osteoarthritis patients, both having undergone hip replacement surgery. A clinical protocol was applied in order to collect CRFs [body mass index (BMI), prior fragility fracture, parental history of hip fracture, long-term use of oral glucocorticoids, rheumatoid arthritis, current smoking, alcohol consumption, age and gender]. The 10-year probability of fracture was calculated. Serum bone turnover markers were determined and dual X-ray absorptiometry performed. Femoral head diameter was evaluated and trabecular bone cylinders were drilled for mechanical testing to determine bone strength, stiffness and toughness. We evaluated 40 hip fragility fracture and 52 osteoarthritis patients. Trabecular bone stiffness was significantly lower (p = 0.042) in hip fragility fracture patients when compared to osteoarthritic individuals, adjusted for age, gender and BMI. No other macrostructural parameter was statistically different between the groups. In hip fragility fracture patients, smoking habits (β = -0.403; p = 0.018) and female gender (β = -0.416; p = 0.008) were independently associated with lower stiffness. In addition, smoking was also independently associated with worse trabecular strength (β = -0.323; p = 0.045), and toughness (β = -0.403; p = 0.018). In these patients, the 10-year risk of major (r = -0.550; p = 0.012) and hip fracture (r = -0.513; p = 0.021) calculated using only CRFs was strongly correlated with femoral neck bone mineral density but not with mechanical performance. Our data showed that among fragility fracture patients active smoking is a predictor of worse intrinsic trabecular mechanical performance, and female gender is also independently associated with lower stiffness. In this population, the 10-year risk of fracture using CRFs with different weights only reflects bone mass loss but not trabecular mechanical properties.
临床风险因素 (CRFs) 是骨折事件的既定预测因子。然而，个体 CRFs 对小梁机械脆弱性的影响仍存在争议。在这项研究中，我们旨在评估髋部脆性骨折患者和骨关节炎患者的骨宏观结构参数之间的差异，这些差异经过 CRFs 调整，并确定个体 CRFs 是否可以预测髋部脆性骨折中的小梁骨机械行为。此外，我们还研究了通过 FRAX 计算的 10 年主要和髋部骨折风险与小梁骨机械性能之间的相关性。在这项病例对照研究中，一组脆性骨折患者与一组骨关节炎患者进行了比较，两组患者均接受了髋关节置换手术。应用临床方案收集 CRFs[体重指数 (BMI)、既往脆性骨折、父母髋部骨折史、长期口服糖皮质激素、类风湿关节炎、当前吸烟、饮酒、年龄和性别]。计算 10 年骨折风险。测定血清骨转换标志物并进行双能 X 线吸收法检查。评估股骨头直径，并钻取小梁骨圆柱进行力学测试，以确定骨强度、刚度和韧性。我们评估了 40 例髋部脆性骨折患者和 52 例骨关节炎患者。调整年龄、性别和 BMI 后，髋部脆性骨折患者的小梁骨刚度明显低于骨关节炎患者（p=0.042）。两组之间没有其他宏观结构参数存在统计学差异。在髋部脆性骨折患者中，吸烟习惯（β=-0.403;p=0.018）和女性（β=-0.416;p=0.008）与较低的刚度独立相关。此外，吸烟也与较差的小梁强度（β=-0.323;p=0.045）和韧性（β=-0.403;p=0.018）独立相关。在这些患者中，仅使用 CRFs 计算的主要（r=-0.550;p=0.012）和髋部骨折（r=-0.513;p=0.021）的 10 年风险与股骨颈骨密度呈强相关，但与力学性能无关。我们的数据表明，在脆性骨折患者中，主动吸烟是较差内在小梁力学性能的预测因子，而女性也是与较低刚度独立相关的因素。在该人群中，使用不同权重的 CRFs 计算的 10 年骨折风险仅反映了骨量丢失，而不反映小梁机械特性。
