Knox Riley, Curran Patrick, Herfat Safa, Kandemir Utku, Marmor Meir
Orthopaedic Trauma Institute, Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA.
OTA Int. 2019 Apr 23;2(3):e034. doi: 10.1097/OI9.0000000000000034. eCollection 2019 Sep.
Mini-fragment plates (MFPs) are increasingly used in fracture surgery to provide provisional fixation. After definitive fixation, the surgeon decides whether to remove the plates or leave them in place as additional fixation, based on the perceived biomechanical influence of the MFP. However, there are no current biomechanical studies to guide this decision. Therefore, the purpose of this study was to evaluate the influence of MFPs on the four-point bending and torsional stiffness of long bone transverse and simple wedge fracture fixation constructs.
Fourth-generation composite bone cylinders were cut to produce transverse (AO-OTA classification 12-A3) and simple wedge (AO-OTA classification 12-B2) fracture models. The specimens were fixed using a low-contact dynamic compression plate (LC-DCP) and MFPs. Specimens were tested in four-point bending and torsion utilizing 3 different MFP orientations.
No statistically significant differences in bending stiffness were found between control and MFP groups for fracture constructs. MFPs significantly increased the bending stiffness for fracture constructs under certain loading conditions. This increase was observed when MFPs were positioned both orthogonal (85.1% increase, .034) and opposite (848.2% increase, .001) to the LC-DCP. MFPs significantly increased the torsional stiffness for both transverse and wedge fracture constructs when MFPs were positioned both orthogonal (transverse: 27.7% increase, wedge: 16.7% increase) and opposite (transverse: 28.4%, wedge: 24.2% increase) to the LC-DCP.
Our results indicate that including MFPs in definitive fixation can increase the bending and torsional stiffness of a long-bone fracture fixation construct. This suggests that the biomechanical influence of MFPs should be considered. However, clinical studies will be required to test the applicability of these findings to the clinical setting.
微型接骨板（MFPs）在骨折手术中越来越多地用于提供临时固定。在进行确定性固定后，外科医生根据对微型接骨板感知到的生物力学影响，决定是取出接骨板还是将其留在原位作为额外固定。然而，目前尚无生物力学研究来指导这一决策。因此，本研究的目的是评估微型接骨板对长骨横行和简单楔形骨折固定结构的四点弯曲和扭转刚度的影响。
将第四代复合骨圆柱体切割制成横行（AO-OTA分类12-A3）和简单楔形（AO-OTA分类12-B2）骨折模型。使用低接触动力加压接骨板（LC-DCP）和微型接骨板固定标本。利用3种不同的微型接骨板方向对标本进行四点弯曲和扭转测试。
对于骨折固定结构，对照组和微型接骨板组之间在弯曲刚度上未发现统计学上的显著差异。在某些加载条件下，微型接骨板显著增加了骨折固定结构的弯曲刚度。当微型接骨板与LC-DCP正交放置（增加85.1%，P = 0.034）和反向放置（增加848.2%，P = 0.001）时均观察到这种增加。当微型接骨板与LC-DCP正交放置（横行：增加27.7%，楔形：增加16.7%）和反向放置（横行：增加2
