Ochman Sabine, Doht Stephanie, Paletta Juergen, Langer Martin, Raschke Michael J, Meffert Rainer H
Department of Trauma, Hand and Reconstructive Surgery, University Hospital, Muenster, Germany.
J Hand Surg Am. 2010 Apr;35(4):597-603. doi: 10.1016/j.jhsa.2010.01.002. Epub 2010 Mar 17.
The use of locking plates increases the primary load to failure, thereby reducing the rate of implant-related failure. The good clinical and biomechanical results of locking plates in long bones might be applicable to treatment of metacarpal fractures. The purpose of this study was to determine strength and stiffness of locking plates in a metacarpal fracture model with mono- and bicortical screw fixation in comparison to non-locking plate mono- and bicortical screw fixation, with both types of plates placed at the dorsal side of the bone.
Fresh second metacarpals from domestic pigs (n=40) were randomized in 4 equal groups. Short, oblique, mid-shaft fractures were generated, using a standardized 3-point bending method. Fractures were plated with non-locking, titanium, 1-mm-thick monocortical (group 1, n=10) or bicortical (group 2, n =10) plates (Leibinger-Stryker; Stryker Corp, Freiburg, Germany). Newly designed locking titanium plates with the same width and thickness (Leibinger-Stryker) were used in the same manner for groups 3 (monocortical) and 4 (bicortical). The metacarpals were then tested to load to failure in a cantilever bending mode.
Bicortical, non-locking fixation (group 2, 359 +/- 90 N) had a higher load to failure than monocortical non-locking fixation (group 1, 250 +/- 56 N) in testing the maximum load to failure (p < .01). There was no significant difference in stiffness between group 1 (46 +/- 12 N/mm) and group 2 (56 +/- 21 N/mm). The difference in maximum load to failure between monocortical (group 3, 440 +/- 85N) and bicortical (group 4, 378 +/- 116 N) locking plate stabilization was not significant. Also, there was no significant difference in stiffness between monocortical (group 3, 83 +/- 35 N/mm) and bicortical locking plates (group 4, 70 +/- 31 N/mm). Comparing non-locking (group 1) and locking plates in a monocortical fixation technique (group 3) demonstrated significant differences in maximum load to failure (group 1, 250 +/- 56 N; group 3, 440 +/- 85 N) and stiffness (group 1, 46 +/- 12 N/mm; group 3, 83 +/- 35 N/mm). The stability of monocortical locking plates was stronger, although not statistically significant, than the non-locking bicortical plates (load to failure, 440 +/- 85 N vs 359 +/- 90 N; stiffness, 83 +/- 35 N/mm vs 56 +/- 21 N/mm).
The new generation of locking plates can be used to achieve a higher stability for fixation of metacarpal fractures. Monocortical, stable fixation can minimize flexor tendon interference and probably reduce bone and soft tissue trauma.
锁定钢板的使用增加了初次失效负荷，从而降低了植入物相关的失败率。锁定钢板在长骨中良好的临床和生物力学结果可能适用于掌骨骨折的治疗。本研究的目的是确定在掌骨骨折模型中，与非锁定钢板单皮质和双皮质螺钉固定相比，锁定钢板单皮质和双皮质螺钉固定的强度和刚度，两种类型的钢板均置于骨的背侧。
将40只家猪的新鲜第二掌骨随机分为4组。采用标准化的三点弯曲方法制造短斜形、骨干中部骨折。骨折处用非锁定的、厚度为1毫米的钛制单皮质（第1组，n = 10）或双皮质（第2组，n = 10）钢板（莱宾格-史赛克；史赛克公司，德国弗莱堡）固定。第3组（单皮质）和第4组（双皮质）以相同方式使用新设计的宽度和厚度相同的锁定钛板（莱宾格-史赛克）。然后将掌骨在悬臂弯曲模式下测试至失效负荷。
在测试最大失效负荷时，双皮质非锁定固定（第2组，359±90 N）的失效负荷高于单皮质非锁定固定（第１组，250±56 N）（p <.01）。第1组（46±12 N/mm）和第2组（56±21 N/mm）之间的刚度无显著差异。单皮质（第3组，440±85N）和双皮质（第4组，378±116 N）锁定钢板固定的最大失效负荷差异不显著。同样，单皮质（第3组，83±35 N/mm）和双皮质锁定钢板（第4组，70±31 N/mm）之间的刚度也无显著差异。比较单皮质固定技术中的非锁定钢板（第1组）和锁定钢板（第3组）显示出最大失效负荷（第1组，250±56 N；第3组，440±85 N）和刚度（第1组，46±12 N/mm；第3组，83±35 N/mm）存在显著差异。单皮质锁定钢板的稳定性比非锁定双皮质钢板更强，尽管无统计学意义（失效负荷，440±85 N对359±90 N；刚度，83±35 N/mm对56±21 N/mm）。
新一代锁定钢板可用于实现掌骨骨折固定的更高稳定性。单皮质稳定固定可将屈肌腱干扰降至最低，并可能减少骨和软组织创伤。
