In this anatomical study, the anteroposterior curvature of the surface of 16 cadaveric distal femurs was examined in terms of radii and center point. Those two parameters attract high interest due to their significance for total knee arthroplasty. Basically, two different conclusions have been drawn in foregoing studies: (1) The curvature shows a constant radius and (2) the curvature shows a variable radius. The investigations were based on a new method combining three-dimensional laser-scanning and planar geometrical analyses. This method is aimed at providing high accuracy and high local resolution. The high-precision laser scanning enables the exact reproduction of the distal femurs—including their cartilage tissue—as a three-dimensional computer model. The surface curvature was investigated on intersection planes that were oriented perpendicularly to the surgical epicondylar line. Three planes were placed at the central part of each condyle. The intersection of either plane with the femur model was approximated with the help of a b-spline, yielding three b-splines on each condyle. The radii and center points of the circles, approximating the local curvature of the b-splines, were then evaluated. The results from all three b-splines were averaged in order to increase the reliability of the method. The results show the variation in the surface curvatures of the investigated samples of condyles. These variations are expressed in the pattern of the center points and the radii of the curvatures. The standard deviations of the radii for a 90 deg arc on the posterior condyle range from 0.6 mm up to 5.1 mm, with an average of 2.4 mm laterally and 2.2 mm medially. No correlation was found between the curvature of the lateral and medial condyles. Within the range of the investigated 16 samples, the conclusion can be drawn that the condyle surface curvature is not constant and different for all specimens when viewed along the surgical epicondylar axis. For the portion of the condylar surface that articulates with the tibia during knee flexion-extension, the determined center points approximate the location of the centers of rotation. The results suggest that the concept of a fixed flexion-extension axis is not applicable for every specimen.

1.
Frankel
,
V. H.
,
Burstein
,
A. B.
, and
Brooks
,
D. B.
, 1972, “
Biomechanics of Internal Derangement of the Knee. Pathomechanics as Determined by Analysis of the Instant Centers of Motion
,”
J. Bone Jt. Surg., Am. Vol.
0021-9355,
53
, pp.
945
97
.
2.
Blacharski
,
P. A.
,
Somerset
,
J. H.
, and
Murray
,
D. G.
, 1975, “
A Three-Dimensional Study of the Kinematics of the Human Knee
,”
J. Biomech.
0021-9290,
8
, pp.
375
384
.
3.
Soudan
,
K.
,
Van Audekercke
,
R.
, and
Martens
,
M.
, 1979, “
Methods, Difficulties and Inaccuracies in the Study of Human Joint Kinematics and Pathokinematics by the Instant Axis Concept. Example: The Knee Joint
,”
J. Biomech.
0021-9290,
12
, pp.
27
33
.
4.
Walker
,
P. S.
,
Shoji
,
H.
, and
Erkman
,
M. J.
, 1972, “
The Rotation Axis of the Knee and Its Significance to Prosthesis Design
,”
Clin. Orthop. Relat. Res.
0009-921X,
89
, pp.
160
170
.
5.
van Dijk
,
R.
,
Huiskes
,
R.
, and
Selvik
,
G.
, 1979, “
Roentgenstereophotogrammetric Methods for the Evaluation of the Three-Dimensional Kinematic Behaviour and Cruciate Ligament Length Patterns of the Human Knee Joint
,”
J. Biomech.
0021-9290,
12
, pp.
727
731
.
6.
Shiavi
,
R.
,
Limbird
,
T.
,
Frazer
,
M.
,
Stivers
,
K.
,
Strauss
,
A.
, and
Abramovitz
,
J.
, 1987, “
Helical Motion Analysis of the Knee—I: Methodology for Studying Kinematics During Locomotion
,”
J. Biomech.
0021-9290,
20
, pp.
459
469
.
7.
Shiavi
,
R.
,
Limbird
,
T.
,
Frazer
,
M.
,
Stivers
,
K.
,
Strauss
,
A.
, and
Abramovitz
,
J.
, 1987, “
Helical Motion Analysis of the Knee—II: Kinematics of Uninjured and Injured Knees During Walking and Pivoting
,”
J. Biomech.
0021-9290,
20
, pp.
653
665
.
8.
Jonsson
,
H.
,
Karrholm
,
J.
, and
Elmqvist
,
L.
, 1989, “
Kinematics of Active Knee Extension After Tear of the Anterior Cruciate Ligaments
,”
Am. J. Sports Med.
0363-5465,
17
, pp.
796
802
.
9.
Jonsson
,
H.
, and
Karrholm
,
J.
, 1994, “
Three-Dimensional Knee Joint Movements During a Step-Up: Evaluation After Anterior Cruciate Ligament Rupture
,”
J. Orthop. Res.
0736-0266,
12
, pp.
769
779
.
10.
Asano
,
T.
,
Akagi
,
M.
, and
Nakamura
,
T.
, 2005, “
The Functional Flexion-Extension Axis of the Knee Corresponds to the Surgical Epicondylar Axis
,”
J. Arthroplasty
0883-5403,
20
, pp.
1060
1067
.
11.
Asano
,
T.
,
Akagi
,
M.
,
Tanaka
,
K.
,
Tamura
,
J.
, and
Nakamura
,
T.
, 2001, “
In Vivo Three-Dimensional Knee Kinematics Using a Biplanar Image Matching Technique
,”
Clin. Orthop. Relat. Res.
0009-921X,
388
, pp.
157
166
.
12.
Eckhoff
,
D. G.
,
Dwyer
,
T. F.
, and
Bach
,
J. M.
, 2001, “
Three-Dimensional Morphology of the Distal Part of the Femur Viewed in Virtual Reality
,”
J. Bone Jt. Surg., Am. Vol.
0021-9355,
83
, pp.
43
50
.
13.
Eckhoff
,
D. G.
,
Bach
,
J. M.
,
Spitzer
,
V. M.
,
Reinig
,
K. D.
,
Bagur
,
M. M.
,
Baldini
,
T. H.
,
Rubinstein
,
D.
, and
Humphries
,
S.
, 2003, “
Three-Dimensional Morphology of the Distal Part of the Femur Viewed in Virtual Reality, Part II
,”
J. Bone Jt. Surg., Am. Vol.
0021-9355,
85
, pp.
97
104
.
14.
Eckhoff
,
D. G.
,
Bach
,
J. M.
,
Spitzer
,
V. M.
,
Reinig
,
K. D.
,
Bagur
,
M. M.
,
Baldini
,
T. H.
, and
Flannery
,
N. M.
, 2005, “
Three-Dimensional Mechanics, and Morphology of the Knee Viewed in Virtual Reality
,”
J. Bone Jt. Surg., Am. Vol.
0021-9355,
87
, pp.
71
80
.
15.
Eckhoff
,
D. G.
,
Hogan
,
C.
,
DiMatteo
,
L.
,
Robinson
,
M.
, and
Bach
,
J. M.
, 2007, “
Difference Between the Epicondylar and Cylindrical Axis of the Knee
,”
Clin. Orthop. Relat. Res.
0009-921X,
461
, pp.
238
244
.
16.
Hollister
,
A. M.
,
Jatana
,
S.
,
Singh
,
A. K.
,
Sullivan
,
W. W.
, and
Lupichuk
,
A. G.
, 1993, “
The Axes of Rotation of the Knee
,”
Clin. Orthop. Relat. Res.
0009-921X,
290
, pp.
259
268
.
17.
Elias
,
S.
,
Freeman
,
M.
, and
Gokcay
,
E.
, 1990, “
A Correlative Study of the Geometry and Anatomy of the Distal Femur
,”
Clin. Orthop. Relat. Res.
0009-921X,
260
, pp.
98
103
.
18.
Iwaki
,
H.
,
Pinskerova
,
V.
, and
Freeman
,
M. A. R.
, 2000, “
Tibio-Femoral Movement 1: The Shapes and Relative Movements of the Femur and Tibia in the Unloaded Cadaver Knee: Studied by Dissection and MRI
,”
J. Bone Jt. Surg., Br. Vol.
0301-620X,
82
, pp.
1189
1195
.
19.
Freeman
,
M. A. R.
, and
Pinskerova
,
V.
, 2003, “
The Movement of the Knee Studied by Magnetic Resonance Imaging
,”
Clin. Orthop. Relat. Res.
0009-921X,
410
, pp.
35
43
.
20.
Pinskerova
,
V.
,
Iwaki
,
H.
, and
Freeman
,
M. A. R.
, 2001, “
The Shapes and Relative Movements of the Femur and Tibia in the Unloaded Cadaveric Knee: A Study Using MRI as an Anatomical Tool
,”
Surgery of the Knee
, Vol.
1
,
Elsevier
,
New York
, pp.
255
283
.
21.
Siu
,
D.
,
Rudan
,
J.
,
Wevers
,
H.
, and
Griffiths
,
P.
, 1996, “
Femoral Articular Shape and Geometry: A Three Dimensional Computerized Analysis of the Knee
,”
J. Arthroplasty
0883-5403,
11
, pp.
166
173
.
22.
Churchill
,
D. L.
,
Incavo
,
J.
,
Johnson
,
C. C.
, and
Beynnon
,
B. D.
, 1998, “
The Transepicondylar Axis Approximates the Optimal Flexion Axis of the Knee
,”
Clin. Orthop. Relat. Res.
0009-921X,
356
, pp.
111
118
.
23.
Maestro
,
A.
,
Harwin
,
S. F.
,
Delvall
,
M.
,
Caballero
,
D.
, and
Murcia
,
A.
, 2000, “
Preoperative Calculation of the Femoral Transepicondylar Axis
,”
Am. J. Knee Surg.
0899-7403,
13
(
3
), pp.
181
187
.
24.
Matsuda
,
S.
,
Miura
,
H.
,
Nagamine
,
R.
,
Mawatari
,
T.
,
Tokunaga
,
M.
,
Nabeyama
,
R.
, and
Iwamoto
,
Y.
, 2004, “
Anatomical Analysis of the Femoral Condyle in Normal and Osteoarthritic Knees
,”
J. Orthop. Res.
0736-0266,
22
, pp.
104
109
.
25.
Piegl
,
L.
, and
Tiller
,
W.
, 1997,
The Nurbs Book
,
2nd ed.
,
Springer
,
Berlin
.
26.
Akagi
,
M.
,
Yamashita
,
E.
,
Nakagawa
,
T.
, and
Nakamura
,
T.
, 2001, “
Relationship Between Frontal Knee Alignment and Reference Axes in the Distal Femur
,”
Clin. Orthop. Relat. Res.
0009-921X,
388
, pp.
147
156
.
27.
Berger
,
R.
,
Rubash
,
H.
,
Seel
,
M.
,
Thompson
,
W.
, and
Crossett
,
L.
, 1993, “
Determining the Rotational Alignment of the Femoral Component in Total Knee Arthroplasty Using the Epicondylar Axis
,”
Clin. Orthop. Relat. Res.
0009-921X,
286
, pp.
40
47
.
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