Farr Joshua N, Amin Shreyasee, Melton L Joseph, Kirmani Salman, McCready Louise K, Atkinson Elizabeth J, Müller Ralph, Khosla Sundeep
College of Medicine, Mayo Clinic, Rochester, MN, USA.
J Bone Miner Res. 2014 Mar;29(3):590-9. doi: 10.1002/jbmr.2071.
Although distal forearm fractures (DFFs) are common during childhood and adolescence, it is unclear whether they reflect underlying skeletal deficits or are simply a consequence of the usual physical activities, and associated trauma, during growth. Therefore, we examined whether a recent DFF, resulting from mild or moderate trauma, is related to deficits in bone strength and cortical and trabecular bone macro- and microstructure compared with nonfracture controls. High-resolution peripheral quantitative computed tomography was used to assess micro-finite element-derived bone strength (ie, failure load) and to measure cortical and trabecular bone parameters at the distal radius and tibia in 115 boys and girls with a recent (<1 year) DFF and 108 nonfracture controls aged 8 to 15 years. Trauma levels (mild versus moderate) were assigned based on a validated classification scheme. Compared with sex-matched controls, boys and girls with a mild-trauma DFF (eg, fall from standing height) showed significant deficits at the distal radius in failure load (-13% and -11%, respectively; p < 0.05) and had higher ("worse") fall load-to-strength ratios (both +10%; p < 0.05 for boys and p = 0.06 for girls). In addition, boys and girls with a mild-trauma DFF had significant reductions in cortical area (-26% and -23%, respectively; p < 0.01) and cortical thickness (-14% and -13%, respectively; p < 0.01) compared with controls. The skeletal deficits in the mild-trauma DFF patients were generalized, as similar changes were present at the distal tibia. By contrast, both boys and girls with a moderate-trauma DFF (eg, fall from a bicycle) had virtually identical values for all of the measured bone parameters compared with controls. In conclusion, DFFs during growth have two distinct etiologies: those owing to underlying skeletal deficits leading to fractures with mild trauma versus those owing to more significant trauma in the setting of normal bone strength.
尽管儿童和青少年时期常见桡骨远端骨折（DFFs），但尚不清楚它们是反映潜在的骨骼缺陷，还是仅仅是生长过程中日常体育活动及相关创伤的结果。因此，我们研究了近期因轻度或中度创伤导致的DFF与非骨折对照相比，是否与骨强度以及皮质骨和小梁骨的宏观和微观结构缺陷有关。采用高分辨率外周定量计算机断层扫描评估115名近期（<1年）发生DFF的8至15岁男孩和女孩以及108名非骨折对照的桡骨远端和胫骨的微有限元衍生骨强度（即破坏载荷），并测量皮质骨和小梁骨参数。根据经过验证的分类方案确定创伤程度（轻度与中度）。与性别匹配的对照相比，轻度创伤DFF（如从站立高度跌落）的男孩和女孩桡骨远端的破坏载荷显著降低（分别为-13%和-11%；p<0.05），且跌落载荷与强度比更高（均为+10%；男孩p<0.05，女孩p=0.06）。此外，与对照相比，轻度创伤DFF的男孩和女孩皮质面积分别显著减少（-26%和-23%；p<0.01），皮质厚度分别显著减少（-14%和-13%；p<0.01）。轻度创伤DFF患者的骨骼缺陷具有普遍性，因为胫骨远端也存在类似变化。相比之下，中度创伤DFF（如从自行车上跌落）的男孩和女孩与对照相比，所有测量的骨参数值几乎相同。总之，生长期间的DFF有两种不同的病因：一种是由于潜在的骨骼缺陷导致轻度创伤骨折，另一种是在骨强度正常的情况下由于更严重的创伤导致骨折。
