微创治疗拇外翻术后绷带外固定:有限元分析截骨端稳定性

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《中国组织工程研究》 Chinese Journal of Tissue Engineering Research

2811

·研究原著·

白子兴,男,1992年生,

河北省邢台市人,汉族,中国中医科学院在读硕士,主要从事骨与关节相关疾病的研究。

通讯作者:孙卫东,主任医师,中国中医科学院望京医院骨关节二科,北京市 100102

文献标识码:A

投稿日期:2019-11-04 送审日期:2019-11-13 采用日期:2019-12-13 在线日期:2020-02-29

Bai Zixing, Master candidate, Second Department of Orthopedics, Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing 100102, China

Corresponding author: Sun Weidong, Chief physician, Second

Department of Orthopedics, Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing 100102, China

微创治疗拇外翻术后绷带外固定:有限元分析截骨端稳定性

白子兴1,曹旭含1,孙承颐2,陈 思1,胡海威1,温建民1,李晏乐1,林新晓1,孙卫东1 (1中国中医科学院望京医院骨关节二科,北京市

100102;2北京中医药大学,北京市 100029)

DOI:10.3969/j.issn.2095-4344.2666 ORCID: 0000-0003-3116-7287(白子兴)

文章快速阅读:

文题释义:

微创治疗拇外翻:根据小夹板纸压垫固定原理,采用1、2趾蹼间夹垫,“8”字绷带和宽胶布作外固定的方法,术后允许患者适当下地活动,进行拇趾关节、踝关节锻炼,避免了患者长期卧床及“石膏病”的发生。经临床应用获得了患者的肯定,总优良率为98.5%。

有限元分析法:有即化整为零、集零为整,通过将研究对象的连续求解区域离散为一组有限个单元,且按一定方式相互联结在一起的单元组合体,由于单元能按不同的联结方式进行组合,且单元本身又可有不同形状,因此可以模拟成不同几何形状的求解小区域,然后对单元进行力学分析,最后再整体分析。

摘要

背景:微创治疗拇外翻临床效果显著,仅通过绷带外固定维持截骨端稳定,目前缺少有关截骨端稳定性的研究。

目的:研究微创治疗拇外翻术后平衡站立工况“8”绷带外固定对截骨端应力和位移的影响。

方法:在微创治疗拇外翻术后“8”字绷带外固定有限元模型上,以第一跖骨截骨面为中心,建立3条两两垂直的坐标轴(X 轴、Y 轴、Z 轴)。X 、Z 轴平行于足水平面,分别指向足内侧、前方;Y 轴垂直于足水平面,指向上方;定义远端截骨面4个节点内上为A 1,外上为B 1,外下为C 1,内下为D 1,近端截骨面对应4个节点为A 2、B 2、C 2、D 2。位移与坐标轴方向一致时为正值,相反时为负值。通过有限元分析得出平衡站立工况截骨面远端及近端各个节点的应力、位移的方向和大小。

结果与结论:①微创治疗拇外翻术后“8”字绷带有限元模型平衡站立工况时,截骨端最大应力在截骨面的背外侧(B 2),为0.632 MPa ;②截骨面第一主应力在Z 轴上,方向与Z 轴相反,与总应力相同,属于压应力;剪切力在XY 平面最大,最大应力在近端截骨面的背内侧(A 2),为0.058 MPa ;③第一跖骨截骨远、近端主要位移在X 轴上,位移分别在截骨面的跖内侧(D 1),为-1.002 mm 、跖内侧(A 2),为0.621 mm ;④结果说明“8”字绷带外固定能够维持微创治疗拇外翻术后截骨端的稳定,有利于截骨端愈合。 关键词:

拇外翻;微创;截骨端;绷带;外固定;有限元;位移;稳定性 中图分类号:R459.9;R687.3;R311 基金资助:

国家自然基金项目(81373802),项目负责人:孙卫东;北京自然科学基金项目(7172244),项目负责人:孙卫东;北京市科技计划课题(Z191100006619024),项目负责人:孙卫东

Minimally invasive treatment of hallux valgus with bandage for external fixation: finite element analysis of stability of the osteotomy end

Bai Zixing 1, Cao Xuhan 1, Sun Chengyi 2, Chen Si 1, Hu Haiwei 1, Wen Jianmin 1, Li Yanle 1, Lin Xinxiao 1,

Sun Weidong 1 (1Second Department of Orthopedics, Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing 100102, China; 2Beijing University of Chinese Medicine, Beijing 100029, China)

白子兴,曹旭含,孙承颐,陈思,胡海威,温建民,李晏乐,林新晓,孙卫东. 微创治疗拇外翻术后绷带外固定:有限元分析截骨端稳定性[J]. 中国组织工程研究,2020,24(18):2811-2816. DOI:10.3969/j.issn.2095-4344.2666

2812

Abstract

BACKGROUND: The clinical effect of minimally invasive treatment of hallux valgus is significant. The osteotomy end is stabilized only by external fixation of the bandage. There is currently no research on the stability of the osteotomy end.

OBJECTIVE: To study the effect of minimally invasive treatment of the “8” bandage external fixation on the stres s and displacement of the osteotomy end in the balanced standing condition after hallux valgus.

METHODS: In the minimally invasive treatment of the “8” bandage external fixation finite element model after the hallux valgus operati on, three vertical axes (X-axis, Y-axis, Z-axis) were established with the first tibial osteotomy as the center. The X-axis and Y-axis were parallel to the horizontal plane of the foot, pointing to the medial and anterior sides of the foot respectively. The Y axis was perpendicular to the

horizontal plane of the foot, pointing upwards. The four nodes defining the distal osteotomy surface were A 1 on the upper side, B 1 on the outer side, and C 1 on the outer side, and D 1 on the inner lower side. The proximal end osteotomy surface corresponded to four nodes as A 2, B 2, C 2 and D 2. The displacement was positive when it coincided with the direction of the coordinate axis, and negative when it was opposite. Through the finite element analysis, the direction and magnitude of the stress and displacement of the distal and proximal nodes of the osteotomy surface in the balanced standing condition were obtained.

RESULTS AND CONCLUSION: (1) The finite element model of the “8” bandage after minimally invasive treatment of hallux valgus was used in a balanced standing condition. The maximum stress at the osteotomy end was at the dorsal side of the osteotomy surface (B 2), which was 0.632 MPa. (2) The first principal stress at the osteotomy surface was at Z-axis. The direction was opposite to the Z-axis, and was the same as the total stress, which was a compressive stress. The shear force was the largest on the XY plane, and the maximum stress was at the dorsal inner side (A 2) of the proximal osteotomy surface, which was 0.058 MPa. (3) The major displacements of the distal and proximal ends of the first patella osteotomy were on the X-axis, and the displacements were on the medial condyle (D 1) of the osteotomy surface, i.e., -1.002 mm and medial condyle (A 2), and 0.621 mm, respectively. (4) The results c onfirm that the external fixation of “8” bandage can maintain the stability of the osteotomy end after minimally invasive treatment of hallux valgus, and is conducive to the healing of the osteotomy end. Key words: hallux valgus; minimally invasive; osteotomy; bandage; external fixation; finite element; displacement; stability

Funding: the National Natural Science Foundation of China, No. 81373802 (to SWD); the Natural Science Foundation of Beijing, No. 7172244 (to SWD); the Science and Technology Project of Beijing, No. Z191100006619024 (to SWD)

0 引言 Introduction

微创治疗拇外翻使用特制削磨钻在第一跖骨远端截骨,无需内固定,仅采用“8”字绷带外固定,患者术后可下地行走,单纯依靠绷带固定截骨端是否稳定、是否影响截骨愈合一直存在争议[1-2]。为进一步研究微创治疗拇外翻术后“8”字绷带外固定对截骨端稳定性的影响,实验通过建立有限元模型模拟微创治疗拇外翻术后“8”绷带外固定平衡站立工况,对截骨端的应力和位移进行计算分析,为微创治疗拇外翻截骨端维持稳定愈合提供科学的解释。

1 材料和方法 Materials and methods

1.1 设计 生物力学实验。

1.2 时间及地点 实验于2018-08-15在中国中医科学院望京医院受试者接待室完成。 1.3 材料

绷带:规格24 cm×600 cm ,4列,经纱21,纬纱32,经纬密度105/10 cm(产品备案号:豫长械备20190037号,新乡市康民卫材开发有限公司)。

医用橡皮膏:规格26 cm×500 cm(批号 201902024,焦作联盟医用材料股份有限公司),剪成20 cm×8 cm 和 26 cm×1.5 cm 橡皮膏条备用。

设备及软件:德国SIEMENS 公司64排螺旋CT(型号SOMATOM Definition Edge);Footscan 平板足底压力测试系统(RSscan 公司,比利时);通用可视化数据库Visualization T oolkit6.0(VTK6.0,Kitware 公司,美国)自动化逆向工程软件Geomagic Studio 12.0(Raindrop Geomagic 公司,美国);ANSYS14.0(ANSYS 软件公司,美国)。 1.4 方法

1.4.1 微创治疗拇外翻术式及外固定方法 微创治疗拇

外翻术式主要包括以下5个步骤:关节囊松解、骨赘磨除、骨赘处理、跖骨截骨、手法矫正,见图1。

绷带外固定主要包括以下3个步骤:①分趾垫的制作与放置:将4列绷带卷成直径约2 cm 的绷带卷,将其折弯,一端放在第1、2趾蹼间,另一端斜行放在第1跖骨截骨远端背侧;②“8”字绷带包扎:绷带从第一跖趾关节内侧开始,环绕前足包扎3圈,经足背侧绕过踝关节外侧,经内踝、足背至第1、2趾蹼间绕过拇趾,自足底经足背至踝关节外侧形成“8”字缠绕,循环包扎3圈;③医用橡皮膏固定:使用26 cm×1.5 cm 医用橡皮膏经足背内侧向趾蹼间行半“8”字环形包扎,保持拇趾轻度内翻位固定;使用20 cm× 8 cm 医用橡皮膏经足背外侧向内侧至足底行“U ”形包扎,见图1。

1.4.2 微创治疗拇外翻术后“8”字绷带外固定有限元模型的建立 招募一位35岁女性拇外翻志愿者,身高165 cm ,体质量50 kg ,患者右足拇外翻角为22°,第1、2跖骨间角为12°,近端关节固定角为5°,远端关节固定角为6°。志愿者足部无

图注:A ,关节囊松解、骨赘磨除、骨赘处理、跖骨截骨;B ,手法

矫正;

C ,绷带外固定 图1 微创治疗拇外翻术式及外固定示意图

[3]

Figure 1 Schema for minimally invasive treatment of hallux valgus

and external fixation [3]

A

B C

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