Wilson David J, Scully William F, Min Kyong S, Harmon Tess A, Eichinger Josef K, Arrington Edward D
Madigan Army Medical Center, Joint Base Lewis McChord, WA, USA.
Martin Army Community Hospital, Ft. Benning, GA, USA.
J Shoulder Elbow Surg. 2016 Jun;25(6):949-53. doi: 10.1016/j.jse.2015.10.006. Epub 2016 Jan 14.
Middle-third clavicle fractures represent 2% to 4% of all skeletal trauma in the United States. Treatment options include intramedullary (IM) as well as plate and screw (PS) constructs. The purpose of this study was to analyze the biomechanical stability of a specific IM system compared with nonlocking PS fixation under low-threshold physiologic load.
Twenty fourth-generation Sawbones (Pacific Research Laboratories, Vashon, WA, USA) with a simulated middle-third fracture pattern were repaired with either an IM device (n = 10) or superiorly positioned nonlocking PS construct (n = 10). Loads were modeled to simulate physiologic load. Combined axial compression and torsion forces were sequentially increased until failure. Data were analyzed on the basis of loss of rotational stability using 3 criteria: early (10°), clinical (30°), and terminal (120°).
No significant difference was noted between constructs in early loss of rotational stability (P > .05). The PS group was significantly more rotationally stable than the IM group on the basis of clinical and terminal criteria (P < .05 for both). All test constructs failed in rotational stability.
When tested under physiologic load, fixation failure occurred from loss of rotational stability. No statistical difference was seen between groups under early physiologic loads. However, during load to failure, the PS group was statistically more rotationally stable than the IM group. Given the clavicle's function as a bony strut for the upper extremity and the biomechanical results demonstrated, rotational stability should be carefully considered during surgical planning and postoperative advancement of activity in patients undergoing operative fixation of middle-third clavicle fractures.
Basic Science Study; Biomechanics.
在美国，中1/3锁骨骨折占所有骨骼创伤的2%至4%。治疗选择包括髓内（IM）以及钢板螺钉（PS）固定。本研究的目的是分析一种特定IM系统与非锁定PS固定在低阈值生理负荷下的生物力学稳定性。
对20个具有模拟中1/3骨折模式的第四代Sawbones（美国华盛顿州瓦申市太平洋研究实验室），分别采用IM装置（n = 10）或高位非锁定PS固定结构（n = 10）进行修复。模拟生理负荷建模加载。依次增加轴向压缩和扭转力直至失效。基于旋转稳定性丧失，使用3个标准（早期[10°]、临床[30°]和末期[120°]）分析数据。
在旋转稳定性早期丧失方面，两种固定结构之间未观察到显著差异（P > 0.05）。基于临床和末期标准，PS组的旋转稳定性明显高于IM组（两者P均< 0.05）。所有测试固定结构均因旋转稳定性丧失而失效。
在生理负荷测试时，固定失效是由于旋转稳定性丧失所致。在早期生理负荷下，两组之间未见统计学差异。然而，在加载至失效过程中，PS组在统计学上的旋转稳定性高于IM组。鉴于锁骨作为上肢骨支柱的功能以及所展示的生物力学结果，在为中1/3锁骨骨折手术固定患者进行手术规划和术后活动推进时，应仔细考虑旋转稳定性。
基础科学研究；生物力学。
