Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute, Vancouver, Canada.
Department of Family Practice, University of British Columbia, Vancouver, Canada.
J Bone Miner Res. 2018 Feb;33(2):229-240. doi: 10.1002/jbmr.3307. Epub 2017 Nov 6.
We recently reported impaired bone strength in girls with low- to moderate-energy distal radius fractures (Fx) compared with girls with no history of forearm fractures (Non-Fx). We aimed to determine whether bone strength deficits observed at baseline were still present after 2 years. We assessed bone strength, microarchitecture, and bone mineral density (BMD) of the non-fractured (Fx) and non-dominant (Non-Fx) distal radius (7% site) at baseline, 12, and 24 months using high-resolution pQCT (Scanco Medical, Brüttisellen, Switzerland) in 104 girls (aged 11.0 ± 1.7 years; 47 Fx, 57 Non-Fx) and 157 boys (aged 12.7 ± 1.7 years; 86 Fx, 71 Non-Fx). Bone outcomes included total area (Tt.Ar) and bone mineral density (Tt.BMD), trabecular bone volume ratio (BV/TV), thickness (Tb.Th), separation (Tb.Sp), and number (Tb.N), and cortical BMD (Ct.BMD), thickness (Ct.Th), and porosity (Ct.Po). We used finite element analysis to estimate bone strength (failure load [F.Load]; ultimate stress [U.Stress]; load-to-strength ratio). We used sex-specific mixed-effects models to compare bone outcomes between Fx and Non-Fx over 2 years. In girls, those with fractures had 18% to 24% lower U.Stress and 5% to 9% lower Tt.BMD than Non-Fx at all time points (p < 0.017). In secondary analysis by fracture degree, girls with low-energy (LE) fractures had 19% to 21% lower F.Load, 25% to 47% lower U.Stress, 11% to 14% lower Tt.BMD, and 11% to 15% lower BV/TV than Non-Fx at all time points (p < 0.017). In contrast, boys' bone outcomes were similar between Fx and Non-Fx at all time points. In secondary analysis by fracture degree, boys with LE fractures had 10% lower Tt.BMD and 10% lower Ct.Th compared with Non-Fx at 12 months only. Deficits in distal radius bone strength and trabecular bone microarchitecture appear to track across 2 years after a forearm fracture in girls but not in boys. Longer follow-up is needed to determine whether deficits persist into adulthood in women and how they may influence future risk of fragility fracture. © 2017 American Society for Bone and Mineral Research.
我们最近报道称，与无前臂骨折史的女孩（非 Fx）相比，低能量至中能量远端桡骨骨折（Fx）的女孩骨骼强度受损。我们旨在确定基线时观察到的骨骼强度缺陷在 2 年后是否仍然存在。我们使用高分辨率 pQCT（Scanco Medical，Brüttisellen，瑞士）评估了 104 名女孩（年龄 11.0±1.7 岁；47 名 Fx，57 名非 Fx）和 157 名男孩（年龄 12.7±1.7 岁；86 名 Fx，71 名非 Fx）的非骨折（Fx）和非优势（非 Fx）远端桡骨（7%部位）的骨骼强度、微观结构和骨密度（BMD）。在基线、12 个月和 24 个月时，骨结局包括总面积（Tt.Ar）和骨密度（Tt.BMD）、骨小梁体积比（BV/TV）、厚度（Tb.Th）、分离度（Tb.Sp）和数量（Tb.N）以及皮质骨密度（Ct.BMD）、厚度（Ct.Th）和孔隙率（Ct.Po）。我们使用有限元分析来估计骨骼强度（失效载荷[F.Load]；最大应力[U.Stress]；载荷与强度比）。我们使用性别特异性混合效应模型来比较 2 年内 Fx 和非 Fx 之间的骨骼结局。在女孩中，与非 Fx 相比，骨折组在所有时间点的 U.Stress 降低 18%至 24%，Tt.BMD 降低 5%至 9%（p<0.017）。在骨折程度的二次分析中，低能量（LE）骨折的女孩在所有时间点的 F.Load 降低 19%至 21%，U.Stress 降低 25%至 47%，Tt.BMD 降低 11%至 14%，BV/TV 降低 11%至 15%（p<0.017）。相比之下，男孩在所有时间点的骨骼结局在 Fx 和非 Fx 之间相似。在骨折程度的二次分析中，LE 骨折的男孩在 12 个月时的 Tt.BMD 和 Ct.Th 比非 Fx 低 10%。在女孩中，桡骨远端骨骼强度和骨小梁微观结构的缺陷似乎在骨折后 2 年内持续存在，但在男孩中并非如此。需要更长时间的随访来确定这些缺陷是否会在女性成年后持续存在，以及它们如何影响未来脆性骨折的风险。
