three-dimensional morphology of the distal part of the femur viewed in virtual reality by donald g....

Three-Dimensional Morphology of the Distal Part of the Femur Viewed in Virtual Reality

by Donald G. Eckhoff, Thomas F. Dwyer, Joel M. Bach, Victor M. Spitzer, and Karl D. Reinig

J Bone Joint Surg AmVolume 83(2 suppl 1):S43-50

October 1, 2001

©2001 by The Journal of Bone and Joint Surgery, Inc.

The stereotactic micrometer, originally designed to localize intracranial lesions in neurosurgery, was modified to hold cadaveric femora for topographical mapping of the condyles and the

trochlear groove.

Donald G. Eckhoff et al. J Bone Joint Surg Am 2001;83:S43-50


The stylus of the micrometer moves horizontally and vertically in millimeter increments to allow measurements of depth, in millimeters, of the articular surface of the condyles and the trochlea

in the horizontal plane.



A side view of the knee simulator, with the femoral unit on the left and the tibial unit on the right.



An end view of the knee simulator, with the viewer looking at the tibial unit from distal to proximal.



Schematic representation of the knee simulator.



A side view of the knee simulator focusing on the details of the flexion/extension actuation.



A table showing the design load capabilities of the knee simulator.



The femoral unit of the knee simulator with the femoral alignment fixture installed.



Forty knees (forty patients) with osteoarthritis of the medial compartment presenting for total knee arthroplasty were scanned with computed tomography, and the measurements were

compared with those for forty normal knees in age-matched controls.



Thirty-four knees (thirty-four patients) with anterior pain were scanned with computed tomography, and the measurements were compared with those for thirty-four normal knees in

age-matched controls.



Computed tomographic scans were performed with the knee in extension by transversely “cutting” the femur proximal to the intercondylar notch and the tibia proximal to the tubercle.



The distal femoral and proximal tibial computed tomography cuts were superimposed to measure relative translation (see Fig. 19) and rotation (see Fig. 20).



The transverse image shown in Fig. 13-A is one of the 1877 1-mm-spaced transverse images of the Visible Human Male.



The transverse image shown in Fig. 14-A is one of the 5189 0.33-mm-spaced transverse images of the Visible Human Female.



The transverse image shown in Fig. 15-A is one of the 2500 0.10-mm-spaced transverse images of a right-knee specimen.



The femur of the Visible Human Male has been extracted from the volumetric computed tomography data represented in Figs. 13-A, 13-B, and 13-C.



The sulcus (lowest point) is a nearly linear depression in the trochlear groove that lies lateral to the midplane, defined as the plane perpendicular to the posterior condylar axis.



The sulcus is oriented between the traditional mechanical axis (the line joining the center of the femoral head and the center of knee) and the anatomic axis (the center of the femoral shaft).



The cross-sectional centers of the distal part of the femur and the proximal part of the tibia are not superimposed but are translated 4±6 mm anteroposteriorly and 5±4 mm

mediolaterally in both normal knees and those with osteoarthritis or ant...



In an extended knee with pathological findings, there is rotation of the tibia in relation to the femur fixed in soft tissue—a “rotation” contracture.



The distal part of the femur is malrotated relative to the proximal part of the femur in the osteoarthritic knees and the knees with anterior pain when compared with the normal knees.



The distal part of the femur of a knee with anterior pain, viewed here with computed tomography, is rotated when the proximal part of the femur is normally oriented in relation to the acetabulum.



Experimental data for eight cadaveric knees.



One view of the Interactive Anatomic Animation of the distal part of the femur illustrates the three-dimensional relationship between the epicondylar axis (green line) and the “cylindrical

axis” (red line), defined by the center of the cylinders that most c...



A femoral component designed with asymmetric features addresses the natural asymmetry of the human knee.



three-dimensional morphology of the distal part of the femur viewed in virtual reality by donald g....

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