AIM To determine factors correlated with postoperative radial shortening in patients with distal radius fractures treated with volar locking distal radius plates.METHODS A total of 250 patients with a distal radius fr...AIM To determine factors correlated with postoperative radial shortening in patients with distal radius fractures treated with volar locking distal radius plates.METHODS A total of 250 patients with a distal radius fracture stabilised with volar locking plates between January 2010 and December 2014 were included in a multicentre retrospective cohort study. We measured the distance of the distal locking screws to the joint line immediately postoperatively and then measured radial shortening after six to eight weeks using the change in ulnar variance.RESULTS Multivariate linear regression analysis showed that there was a significant linear association between the distance of the screws from the joint line and radial shortening. No other patient, injury, or treatment-related characteristic significantly influenced radial shortening in multivariate analysis.CONCLUSION Distal locking screws should be placed as close as possible to the subchondral joint line to prevent postoperative loss of reduction.展开更多
文摘AIM To determine factors correlated with postoperative radial shortening in patients with distal radius fractures treated with volar locking distal radius plates.METHODS A total of 250 patients with a distal radius fracture stabilised with volar locking plates between January 2010 and December 2014 were included in a multicentre retrospective cohort study. We measured the distance of the distal locking screws to the joint line immediately postoperatively and then measured radial shortening after six to eight weeks using the change in ulnar variance.RESULTS Multivariate linear regression analysis showed that there was a significant linear association between the distance of the screws from the joint line and radial shortening. No other patient, injury, or treatment-related characteristic significantly influenced radial shortening in multivariate analysis.CONCLUSION Distal locking screws should be placed as close as possible to the subchondral joint line to prevent postoperative loss of reduction.
文摘电离层不规则结构的存在可引起无线电信号的幅度和相位发生随机起伏,这种电离层闪烁现象会影响全球定位系统(Global Positioning System,GPS)的性能,降低定位精度,严重时导致信号失锁.电离层不规则结构对GPS性能的影响涉及电离层物理、接收机设计和表征卫星几何分布的精度衰减因子(Dilution of Positioning,DOP)等多方面因素.本文通过对表征电离层不规则结构参数的分析,根据GPS接收机跟踪环路和闪烁信号模型,综合研究了电离层闪烁对GPS接收机载波跟踪环和码跟踪环跟踪误差的影响;结合实际观测,评述了电离层不规则结构对单频和双频GPS接收机定位性能的影响,在此基础上提出了有待深入研究的问题及具体建议.
