Department of Orthopaedic Surgery, Balboa Naval Medical Center-San Diego, 34800 Bob Wilson Drive, San Diego, CA 92134-5000, USA.
J Orthop Trauma. 2011 Jan;25(1):44-50. doi: 10.1097/BOT.0b013e3181d7a3a6.
The purpose of this study was to gain insight into the effect of plate location and screw type for fixation of extra-articular distal radius fractures with dorsal comminution (Orthopaedic Trauma Association Type 23-A3.2).
Sixteen pairs of cadaver radii were randomized to four plating configurations: dorsal locking, dorsal nonlocking, volar locking, and volar nonlocking. A standard 1-cm dorsal wedge osteotomy was used. Cyclic axial loads were applied for 5000 cycles. Stiffness and fragment displacement were recorded at 500 cycle-intervals. Pre- and postcyclic loading radiographs were analyzed. An axial load to failure test followed and construct stiffness and failure strength recorded. Biomechanical data were analyzed using a two-way analysis of variance (P < 0.05). Failure modes were descriptively interpreted.
Cyclic testing data revealed no difference between constructs at any interval. Within all construct groups, displacement that occurred did so within the first 500 cycles of testing. Pre- and postcyclic loading radiographic analysis showed no differences in construct deformation. Load to failure testing revealed no differences between groups, whereas volar constructs approached significance (P = 0.08) for increased failure strength. Dorsal constructs failed primarily by fragment subsidence and fragmentation, whereas volar constructs failed by plate bending.
No difference in all measured biomechanical parameters supports equivalence between constructs and surgeon discretion in determining operative method. Minimal fragment displacement and construct deformation during physiological testing support previous data that early postoperative motion can be recommended. Fragment displacement that occurs does so in the early periods of motion.
本研究旨在深入了解背侧粉碎性（骨科创伤协会 23-A3.2 型）关节外桡骨远端骨折固定时钢板位置和螺钉类型的影响。
将 16 对 cadaver 桡骨随机分为 4 种钢板固定方式：背侧锁定、背侧非锁定、掌侧锁定和掌侧非锁定。采用标准 1cm 背侧楔形截骨术。施加 5000 个循环的循环轴向载荷。在 500 个循环间隔记录刚度和碎片位移。分析预加载和加载后的放射照片。随后进行轴向失效测试，并记录结构刚度和失效强度。使用双向方差分析（P < 0.05）分析生物力学数据。对失效模式进行描述性解释。
循环测试数据表明，在任何间隔内，结构之间均无差异。在所有结构组中，位移都发生在测试的前 500 个循环内。预加载和加载后放射照片分析显示，结构变形无差异。失效测试表明各组之间无差异，而掌侧结构接近显著性（P = 0.08），失效强度增加。背侧结构主要通过碎片下沉和碎裂失效，而掌侧结构则通过钢板弯曲失效。
所有测量的生物力学参数均无差异，这支持了结构之间的等效性，并且外科医生在确定手术方法时有自主裁量权。在生理测试中，最小的碎片位移和结构变形支持了早期术后运动可被推荐的先前数据。发生的碎片位移发生在运动的早期阶段。
