Establishment and preliminary application of measuring method for three-dimensional kinematics of the hindfoot joint in vivo / 中华骨科杂志

ABSTRACT

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 towards 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 adduction,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.