胸锁关节解剖锁定钢板的研制及生物力学研究

Development and biomechanical study of anatomical locking plate of sternoclavicular joint

目的研制符合胸锁关节解剖学特点、固定可靠、手术操作简便的解剖锁定钢板,为治疗胸锁关节脱位或周围骨折提供一种理想的内固定器械。方法取8具(16侧)成人防腐、湿润胸锁关节标本,分别采用大体测量和CT测量胸锁关节周围骨性结构参数(包括胸骨柄厚度、胸骨切迹宽度、锁骨近端1/3的前后径、锁骨近端1/3的上下径、锁骨近端与胸骨柄在冠状面的夹角、胸锁关节在解剖位向前的成角),设计并研制出胸锁关节解剖锁定钢板。标本均用手术刀完全切断胸锁韧带及关节囊,造成胸锁关节完全脱位模型。将每具标本的左、右侧胸锁关节随机配对分为试验组(解剖型锁定钢板固定)和对照组(斜T形锁定钢板固定)。在万能力学试验机上模拟胸锁关节活动及常见受力机制,分别进行锁骨远端负载、胸锁关节扭转、钢板螺钉抗拔出3项生物力学性能测试。结果标本大体测量与CT测量的各项解剖学参数比较差异均无统计学意义(P>0.05)。锁骨远端负载试验中,在解剖位垂直于锁骨远端向后加载至20 N时,试验组加载点的位移为(8.455±0.981)mm,显著小于对照组的(10.163±1.379)mm(t=–3.012,P=0.020);两组锁骨远端向上加载点的位移[分别为(5.427±1.154)、(6.393±1.040)mm]比较差异无统计学意义(t=–1.459,P=0.188)。胸锁关节扭转试验中,顺时针扭角为2、4、6、8、10°时以及逆时针扭角为4、6、8、10°时,试验组扭矩显著大于对照组(P<0.05)。顺时针和逆时针扭转时试验组扭转刚度分别为0.122、0.108 N·m/°,均显著高于对照组的0.083、0.078 N·m/°(F=67.824,P=0.000;F=20.992,P=0.002)。钢板螺钉抗拔出试验中,试验组最大抗拔出力为(225.24±16.02)N,显著大于对照组的(174.40±21.90)N(t=5.785,P=0.001)。结论新设计的胸锁关节解剖锁定钢板可实现胸锁关节的三维固定,具有固定可靠、手术操作简便、创伤小、生物力学性能优越、利于早期功能锻练的优势,可能成为临床治疗胸锁关节脱位及周围骨折的一种较理想的内固定器械。

Objective To develop an anatomical locking plate in accordance with the anatomical characteristics of the sternoclavicular joint, which is reliable fixation and easy to operate, so as to provide an ideal internal fixation device for the treatment of sternoclavicular joint dislocation or peripheral fractures. Methods Gross measurement and CT measurement were performed on the 8 adult antiseptic and moist cadaver specimens（16 sides） to measure the parameters of surrounding bone structure of the sternoclavicular joint. The parameters included the thickness of presternum, sternal notch width, anteroposterior diameter of proximal 1/3 of clavicle, upper and lower diameters of proximal 1/3 of clavicle,angle between proximal end of clavicle and presternum in coronal plane, and angle of thoracoclavicular joint at anatomic position forward. According to the anatomical parameters and biomechanical properties of the specimens, the anatomical locking plate was designed and developed. The sternoclavicular ligament and joint capsule of all the specimens were completely cut off to make the sternoclavicular joint dislocation model. The left and right sternoclavicular joint of each specimen were randomly divided into experimental group（anatomic locking plate fixation） and control group（oblique T shape locking plate fixation）. The sternoclavicular joint activity and common force mechanism was simulated on the universal mechanical testing machine, and the clavicular distal load test, sternoclavicular joint torsion test, and antipulling of steel plate manubrium part test were performed. Results The differences between the anatomical parameters of gross measurement and CT measurement were not significant（P0.05）. In the clavicular distal load test, when the anatomical position perpendicular to the distal clavicle back loading to 20 N, the displacement of loading point in the experimental group was（8.455±0.981） mm, which was significantly less than that in control group [（10.163±1.379） mm]（t=–3.012, P=0.020）; the distal clavicle displacement of loading point of experimental group and control group were（5.427±1.154） mm and（6.393±1.040） mm, respectively, showing no significant difference（t=–1.459, P=0.188）.In the sternoclavicular joint torsion test, the torque of experimental group was significantly greater than that of control group when the clockwise torsion angle was at 2, 4, 6, 8, and 10 degrees and the counterclockwise torsion angle was at 4, 6, 8, and 10 degrees（P0.05）. The torsional stiffness in the experimental group under clockwise and counterclockwise condition was 0.122 and 0.108 N·m/° respectively, which were significantly higher than those in the control group（0.083 and 0.078 N·m/° respectively）（F=67.824, P=0.000; F=20.992, P=0.002）. In the anti-pulling of steel plate manubrium part test,the maximum pullout force of experimental group [（225.24±16.02） N] was significantly higher than that in control group[（174.40±21.90） N]（t=5.785, P=0.001）. Conclusion The new type of anatomical locking plate can realize the sternoclavicular joint three-dimensional fixation, and has the advantages of reliable fixation, simple operation, less trauma,superior biomechanical properties, and earlier functional exercise. It may be an ideal internal fixation device in clinical treatment of sternoclavicular joint dislocation or peripheral fractures.