基于足踝三维有限元模型的摇拔戳手法治疗外侧踝关节扭伤关节面力学分析

Mechanical Analysis of Lateral Ankle Sprain Treated by Rotating-pulling-poking Manipulation based on Three-dimensional Finite Element Model

目的探讨摇拔戳手法治疗外侧踝关节扭伤的力学调衡作用机理。方法运用1例急性外侧踝关节扭伤患者胫骨远端1/3以下的踝部CT断层扫描图片,通过Abaqus 6.13和Mimics10.0软件构建足踝三维有限元模型,并采用摇拔戳手法治疗,隔日1次,疗程为2周。于手法治疗前、初次治疗后、疗程结束后2周进行在体试验力学数据采集及转化,将数据转化后的相关力学参数代入有限元模型中,比较摇拔戳手法治疗外侧踝关节扭伤3个时间点的4种踝关节工况(跖屈、背伸、内翻、外翻)下关节面应力峰值及应力分布面积变化。结果在体试验结果示,4种踝关节工况下在3个不同时间点踝关节的最大运动角度均逐渐增大,其中背伸工况下治疗前、初次治疗后、疗程结束后2周踝关节的最大运动角度分别为26.5°、27.5°、31.7°。有限元加载试验结果显示,4种踝关节工况下,在3个不同时间点距骨与胫骨、腓骨的两个关节接触面的应力载荷峰值逐渐升高,应力分布面积逐渐增大。其中背伸工况下,治疗前距骨与胫骨关节接触面的应力载荷峰值为49.5 MPa,应力分布面积为131.04 mm^(2),初次治疗后分别为50.0 MPa、146.88 mm^(2),疗程结束后2周分别为52.4 MPa、218.88 mm^(2);治疗前距骨与腓骨关节接触面的应力载荷峰值为26.5 MPa,应力分布面积为226.08 mm^(2),初次治疗后分别为27.5 MPa、237.60 mm^(2),疗程结束后2周分别为32.5 MPa、269.28 mm^(2)。结论摇拔戳手法能够有效改善外侧踝关节扭伤踝穴关节面的应力分布情况,使踝关节面的载荷承重能力逐渐增加,应力分布逐渐趋于均匀化,从而使扭伤后踝关节活动受限的症状得以改善,这可能是摇拔戳手法治疗外侧踝关节扭伤的力学调衡作用机制之一。

Objective To explore the mechanism of mechanical adjustment in the treatment of lateral ankle sprain by rotating,pulling and poking.Methods The CT tomographic image of the ankle below the distal 1/3 of the tibia in one case of acute lateral ankle sprain was collected,and the three-dimensional finite element model of the ankle was constructed by Abaqus 6. 13 and Mimics 10. 0 software. Rotating,pulling and poking manipulation were performed,once every other day for two weeks. The mechanical data of in vivo tests were collected and transformed before the manipulation,after initial treatment,and after 2-week treatment,and the transformed mechanical parameters were substituted into the finite element model to analyze the stress peak value and stress distribution area of the articular surface under the four ankle joint working conditions(plantar flexion,dorsiflexion,eversion,inversion)at three time points in the treatment of lateral ankle sprain by rotating-pulling-poking manipulation.Results The results of in vivo tests showed that with the passage of time,the maximum motion angle of the ankle joint increased gradually at three time points under the four working conditions,and that was 26. 5°,27. 5°,and 31. 7° before treatment,after initial treatment,and after 2-week treatment under the condition of dorsiflexion,respectively. The finite element loading test showed that the stress peak value and stress distribution area of talus fibular surface and talus tibial surface gradually increased with the passage of time at three time points under the four working conditions of ankle joints. Under dorsiflex2ion condition,the stress peak value and stress distribution area of talus tibial surface were 49. 5MPa and131. 04 mm^(2)respectively,while those were 50. 0 MPa and 146. 88 mm^(2) after initial treatment,and 52. 4 MPa and218. 88 mmafter 2-week treatment;for talus fibular surface,the stress peak value and stress distribution area were 26. 5 MPa and 226. 08 mm^(2) before treatment,227. 5 MPa and 237. 60 mm^(2) after initial treatment,and 32. 5 MPa and269. 28 mmafter 2-week treatment,respectively.Conclusion Rotating-pulling-poking manipulation can effectively improve the stress distribution on the articular surface of the ankle point for sprained lateral ankle joint,so that the load-bearing capacity of the ankle joint surface is gradually raised,and the stress distribution is gradually distributed evently,thereby improving the symptoms of limited ankle motion after sprain. This may be one of the mechanism of mechanical adjustment in the treatment of lateral ankle sprain by rotating-pulling-poking manipulation.