Goodwin Jill, Castañeda Paulo, Drace Patricia, Edwards Scott
Department of Orthopaedic Surgery, University of Arizona College of Medicine, Phoenix, Arizona.
J Wrist Surg. 2018 Feb;7(1):77-80. doi: 10.1055/s-0037-1606123. Epub 2017 Aug 14.
Headless screw fixation is the current gold standard of surgical repair for scaphoid fractures. However, maintaining reduction of certain types of scaphoid fractures is challenging with a compression screw. Plate fixation may offer superior fixation in some scaphoid fractures, particularly those with comminution, nonunion, segmental bony defects, and osteopenic or osteoporotic bone. This study questions whether method of fixation is a determinant in load to failure in segmental scaphoid fractures, and whether any fixation provides a greater mechanical advantage in simulated normal versus osteoporotic bone. Polyurethane models were fashioned to simulate scaphoids with 3-mm segmental defects. Defects were bridged by one of three constructs: a locking plate, a nonlocking plate, or a headless compression screw. Three models for each fixation construct were tested for both simulated normal and osteoporotic bone density. Load to failure was recorded as the load at which the 3-mm segmental defect was closed. Gap closure occurred in all trials. In simulated normal bone, there were no statistically significant differences in load to failure between fixation methods. In simulated osteoporotic bone, the locking plate had a 28% greater load to failure as compared with screw fixation. While biomechanical testing shows that plate and screw fixations are equivalent in normal density bone for fixation of a segmental scaphoid defect, locking plates are superior to screw fixation in simulated osteoporotic bone models. Plate fixation may provide superior fixation for complex scaphoid fractures, particularly in osteopenic bone.
无头螺钉固定是目前舟骨骨折手术修复的金标准。然而，使用加压螺钉维持某些类型舟骨骨折的复位具有挑战性。钢板固定在一些舟骨骨折中可能提供更好的固定效果，特别是那些伴有粉碎性骨折、骨不连、节段性骨缺损以及骨质减少或骨质疏松的骨折。 本研究探讨固定方法是否是节段性舟骨骨折失败负荷的决定因素，以及在模拟正常骨与骨质疏松骨中，哪种固定方式具有更大的机械优势。 制作聚氨酯模型以模拟具有3毫米节段性缺损的舟骨。缺损由以下三种结构之一进行桥接：锁定钢板、非锁定钢板或无头加压螺钉。对每种固定结构的三个模型分别进行模拟正常骨密度和骨质疏松骨密度测试。将失败负荷记录为3毫米节段性缺损闭合时的负荷。 在所有试验中均出现间隙闭合。在模拟正常骨中，不同固定方法之间的失败负荷无统计学显著差异。在模拟骨质疏松骨中，与螺钉固定相比，锁定钢板的失败负荷高28%。 虽然生物力学测试表明，在固定节段性舟骨缺损时，钢板和螺钉固定在正常密度骨中效果相当，但在模拟骨质疏松骨模型中，锁定钢板优于螺钉固定。 钢板固定可能为复杂舟骨骨折提供更好的固定效果，特别是在骨质减少的骨中。
