Jk. Udupa et al., ANALYSIS OF IN-VIVO 3-D INTERNAL KINEMATICS OF THE JOINTS OF THE FOOT, IEEE transactions on biomedical engineering, 45(11), 1998, pp. 1387-1396
This paper describes a methodology for the analysis of three-dimension
al (3-D) kinematics of live joints of the foot based on tomographic im
age data acquired via magnetic resonance (MR) imaging. A mechanical ji
g facilitates acquisition of MR images corresponding to different posi
tions of the joint in a pronation-supination motion. The surfaces of t
he individual tarsal bones are constructed by segmenting the MR images
. A mathematical description of the motion of the individual bones and
of their relative motion is derived by computing the rigid transforma
tion required to match the centroids and the principal axes of the sur
faces. The mathematically described motion is animated via surface ren
ditions of the bones, The kinematics of the bones are analyzed based o
n features extracted from the motion description and on how they vary
with motion. Based on 17 joints that have been imaged, which includes
an abnormal joint and the same joint after surgical correction, we con
clude that this methodology offers a practical tool for measuring inte
rnal 3-D kinematics of joints in vivo and for characterizing and quant
ifying with specificity normal kinematics and their pathological devia
tions. Some of the 3-D kinematic animations generated using the method
s of this paper for normal joints can be seen at: http://www.mipg.upen
n.edu.