A new method for deriving limb segment motion from markers placed on the skin is described. The method provides a basis for determining the artifact associated with nonrigid body movement of points placed on the skin. The method is based on a cluster of points uniformly distributed on the limb segment. Each point is assigned an arbitrary mass. The center of mass and the inertia tensor of this cluster of points are calculated. The eigenvalues and eigenvectors of the inertia tensor are used to define a coordinate system in the cluster as well as to provide a basis for evaluating non-rigid body movement. The eigenvalues of the inertia tensor remain invariant if the segment is behaving as a rigid body, thereby providing a basis for determining variations for nonrigid body movement. The method was tested in a simulation model where systematic and random errors were introduced into a fixed cluster of points. The simulation demonstrated that the error due to nonrigid body movement could be substantially reduced. The method was also evaluated in a group of ten normal subjects during walking. The results for knee rotation and translation obtained from the point cluster method compared favorably to results previously obtained from normal subjects with intra-cortical pins placed into the femur and tibia. The resulting methodology described in this paper provides a unique approach to the measurement of in vivo motion using skin-based marker systems.

1.
Andriacchi, T. P., Sen, K., Toney, M. K., and Yoder, D., 1994, “New developments in musculoskeletal functional testing,” Proc. Canadian Soc. of Biomechanics, VIIIth Biennial Conf., pp. 12–13.
2.
Andriacchi, T. P., and Toney, M. K., 1995, “In Vivo Measurement of Six-Degrees-of-Freedom Knee Movement During Functional Testing,” in: Trans. 41 Ann. Meet. Orth. Res. Soc., Orlando, FL, p. 698.
3.
Banks
S. A.
, and
Hodge
W. A.
,
1996
, “
Accurate measurement of three-dimensional knee replacement kinematics using single-plane fluoroscopy
,”
IEEE Trans. Biomed. Eng.
,
43
(
6)
,
638
649
.
4.
Benedetti, M. G., and Cappozzo, A., 1994, “Anatomical landmark definition and identification in computer aided movement analysis in a rehabilitation context II (Internal Report),” Universita Degli Studi La Sapienza, 1–31.
5.
Cappello, A., Cappozzo, A., La Palombara, P. F., Leardini, A., and Bertani, A., 1996, “Skin artifact compensation by double calibration in bone motion reconstruction,” Paper No. 2.6.3–2, presented at the 18th Annual Int. Conf. of the IEEE Engineering in Medicine and Biology Society.
6.
Cappozzo
A.
,
Catani
F.
,
Leardini
A.
,
Benedetti
M. G.
, and
Della Croce
U.
,
1996
, “
Position and orientation in space of bones during movement: experimental artifacts
,”
Clinical Biomechanics
,
11
,
90
100
.
7.
Dyrby
C. O.
,
Toney
M. K.
, and
Andriacchi
T. P.
,
1997
, “
Relation between knee flexion and tibial-femoral rotation during activities involving deep flexion
,”
Gait and Posture
,
5
,
179
179
.
8.
Hatze
H.
,
1988
, “
High-precision three-dimensional photogrammetric calibration and object space reconstruction using a modified DLT-approach
,”
J. Biomechanics
,
21
,
533
538
.
9.
Holden
J. P.
,
Orsini
J. A.
,
Siegel
K. L.
,
Kepple
T. M.
,
Gerber
L. H.
, and
Stanhope
S. J.
,
1997
, “
Surface movement errors in shank kinematics and knee kinetics during gait
,”
Gait and Posture
,
3
,
217
227
.
10.
Hoppenfeld, S., and Huton, R., 1976, “Physical examination of the knee,” Physical Examination of the Spine and Extremities, 171–196.
11.
Jonsson
H.
, and
Ka¨rrholm
J.
,
1994
, “
Three-dimensional knee joint movements during a step-up: evaluation after anterior cruciate ligament rupture
,”
J. Orthop. Res.
,
12
(
6)
,
769
779
.
12.
LaFortune
M. A.
,
Cavanagh
P. R.
,
Sommer
H. J.
, and
Kalenak
A.
,
1992
, “
Three dimensional kinematics of the human knee during walking
,”
J. Biomechanics
,
25
,
347
357
.
13.
Levenberg
K.
,
1944
, “
A method for the solution of certain problems in least squares
,”
Quart. Apl. Math.
,
2
,
164
168
.
14.
Marquardt
D.
,
1963
, “
An algorithm for least-squares estimation of nonlinear parameters
,”
SIAM J. Appl. Math.
,
11
,
431
441
.
15.
Maslen
B. A.
, and
Ackland
T. R.
,
1994
, “
Radiographic study of skin displacement errors in the foot and ankle during standing
,”
Clinical Biomechanics
,
9
,
291
296
.
16.
Murphy, M. C., 1990, “Geometry and the Kinematics of the Normal Human Knee,” Ph.D. thesis, Massachusetts Institute of Technology, Cambridge, MA.
17.
Reinschmidt, C., van den Bogert, A. J., Lundberg, A., Murphy, N., and Nigg, B. M., 1995, “Tibiofemoral and calcaneus-tibia motion during running: skin vs. bone markers,” in: Conference Proceedings, American Society of Biomechanics, Stanford, 41–42.
18.
Sati
A.
,
de Guise
J. A.
,
Larouche
S.
, and
Drouin
G.
,
1996
, “
Quantitative assessment of skin-bone movement at the knee
,”
The Knee
,
3
,
121
138
.
19.
Spoor
C. W.
, and
Veldpaus
F. E.
,
1980
, “
Rigid body motion calculated from spatial co-ordinates of markers
,”
J. Biomechanics
,
13
,
391
393
.
20.
Stein
L. A.
,
Endicott
A. N.
,
Sampalis
J. S.
,
Kaplow
M. A.
,
Patel
M. D.
, and
Mitchell
N. S.
,
1993
, “
Motion of the patella during walking: A video digital-fluoroscopic study in healthy volunteers
,”
Amer. J. Roentgenology
,
161
,
618
620
.
21.
Stiehl
J. B.
,
Komistek
R. D.
,
Dennis
D. A.
,
Paxson
R. D.
, and
Hoff
W. A.
,
1995
, “
Fluoroscopic analysis of kinematics after posterior-cruciate-retaining knee arthroplasty
,”
J. Bone Joint Surg. Br.
,
77
,
884
889
.
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