Ilyas Asif M, Hayward Gerald M, Harris Jonathan A, Wang Wenhai, Bucklen Brandon S
Department of Orthopaedic Surgery, Rothman Institute, Thomas Jefferson University, Philadelphia, Pennsylvania.
Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical Inc., Audubon, Pennsylvania.
J Wrist Surg. 2020 Dec;9(6):475-480. doi: 10.1055/s-0040-1713419. Epub 2020 Jul 6.
Bridge plating for distal radius fractures is indicated for complex fractures with comminution, extensive articular involvement, and/or cases requiring immediate weight bearing. Bridge plate fixation of distal radius fractures is a well-documented treatment method; however, failures have been reported with repetitive loading through the bridged distal radius fracture. Plate design is implicated as a cause of plate fracture in select clinical studies but few mechanical tests comparing bridge plate designs have been reported. This study sought to determine the impact of plate design on bridge plates intended to allow for immediate weight-bearing. Axial static ( = 3) and dynamic testing ( = 3) was performed on three distraction plates designs: bridge plate 1 (BP1) with central holes, bridge plate 2 (BP2) without central holes, and locking compression plate (BP3). Plates were loaded in axial compression with a simulated 10-mm fracture gap. Significant static load differences were noted between all groups. Static load to failure for BP1, BP3, and BP2 were 240 ± 5 N, 398 ± 9 N, and 420 ± 3 N, respectively ( < 0.05). BP1 was the only plate series that failed during dynamic testing; all other plates achieved 100,000 cycles. Failure mode was a fracture occurring through the central screw hole of BP1. Finite element analysis demonstrated the effects of central screw holes on stress, strain, and plastic deformation under loading. Unused screw holes are the mechanical weak points; plates designed without these central screw holes are expected to survive greater load values. The threshold for clinical importance will need to be determined by future studies.
桡骨远端骨折的桥接钢板固定适用于伴有粉碎、广泛关节受累的复杂骨折和/或需要立即负重的病例。桡骨远端骨折的桥接钢板固定是一种有充分文献记载的治疗方法；然而，有报道称，通过桥接的桡骨远端骨折进行反复加载会导致固定失败。在一些临床研究中，钢板设计被认为是钢板断裂的一个原因，但很少有比较桥接钢板设计的力学测试报告。本研究旨在确定钢板设计对旨在允许立即负重的桥接钢板的影响。 对三种撑开钢板设计进行了轴向静态（n = 3）和动态测试（n = 3）：有中心孔的桥接钢板1（BP1）、无中心孔的桥接钢板2（BP2）和锁定加压钢板（BP3）。钢板在轴向压缩下加载，模拟10毫米的骨折间隙。 所有组之间均观察到显著的静态载荷差异。BP1、BP3和BP2的静态破坏载荷分别为240±5 N、398±9 N和420±3 N（P < 0.05）。BP1是唯一在动态测试中失败的钢板系列；所有其他钢板均达到100,000次循环。失败模式是BP1的中心螺孔处发生骨折。有限元分析表明了中心螺孔在加载下对应力、应变和塑性变形的影响。 未使用的螺孔是力学薄弱点；预计没有这些中心螺孔的钢板设计能够承受更大的载荷值。临床重要性的阈值需要未来的研究来确定。
