后足关节在体运动度测量新方法的建立和初步应用

Establishment and preliminary application of measuring method for three.dimensional kinematics of the hindfoot joint in vivo

目的利用逆向工程软件结合刚体运动学原理，建立后足各关节在体三维运动度测量的新方法。方法采集5名健康志愿者（男4名，女1名）9足在中立位和最大内翻、内收、背伸位的后足CT影像．使用MIMICS 10．01软件对这两个体位的后足关节进行图像分割及三维重建，建立后足关节三维数字化模型，将重建的后足关节模型以．STL格式导人GEOMAGIC10．0软件中进行2次注册配准，利用GEOMAGIC 10．0软件的Edit transform功能计算并读取胫距、距下、距舟关节三维空间相对角度和位移变化。结果足由中立位进行内翻、内收、背伸运动时，胫距关节背伸10．77°±5．70°、外翻3．89°±2．77°、外展5．29°±4．47°，向足外侧位移（0．78±0．59）mm、向后足位移（0．18±0．75）mm、向肢体近侧位移（0．65±0．71）mm：距下关节跖屈6．330±4．32°、内翻16．46°±2．94°、内收12．77°±1．81°，向足内侧位移（5．50±1．45）mm、向前足位移（1．96±1．77）mm、向肢体远侧位移（0．43±1．18）mm；距舟关节跖屈5．09。±6．89。、内翻38．82。±5．980、内收19．71。±6-33。，向足内侧位移（9．77±1．73）mm、向后足位移（3．13±1．29）mm、向肢体近侧位移（4．64±1．42）mm。结论建立了后足关节在体三维运动度测量的新方法，该方法具有非侵入性、可视窗化操作以及简便易行的特点。

Objective To establish a new method for measuring the 3-D kinematics of hindfoot joints in vivo by using reverse engineering software together with the theory of rigid body kinematics. Methods CT images were gathered from 9 feet of 5 healthy volunteers in both the initial position （neutral position） and the terminal position （extremely inversion-adduction-dorsiflexion position）. The 3-D digital modules of hindfoot joints in the initial position and terminal position were established with MIMICS 10.01 software. The data of reconstructed digital modules was inputted into the GEOMAGIC 10.0 software in STL format for twice registration, and then their relatively displacement and changes of angle in 3-D space between the two positions were calculated Results The rotation range of the tibiotalar joint was 3.89°±2.77° in eversion, 5.29°±4.47° in abduction, 10.77°±5.70° in dorsiflexion, and the relative displacement was 0.78±0.59 mm to- wards lateral ankle, 0.18±0.75 mm towards the hindfoot, （0.65±0.71） mm towards the proximal limbs;the range of subtalar joint was 16.46°±2.94° in inversion, 12.77°±1.81° in adduetion, 6.33°±4.32° in plantarflexion, and the relative displacement was 5.50±1.45 mm towards medial ankle, 1.96±1.77 mm towards forefoot, 0.43±1.18 mm towards distal limbs; the range of talonavicular joint was 38.82°±5.98° in inversion, 19.71°±6.33° in adduction, 5.09°±6.89° in plantarflexion, and the relative displacement was （9.77_＋1.73） mm towards medial ankle, 3.13±1.29 mm towards hindfoot, 4.64±1.42 mm towards proximal limbs. Conclusion This method measuring 3-D kinematics of hindfoot joints in vivo is non-invasive and easy to operate.