Transcript FEMUR PROKSIMALNI OKRAJAK - ICIT

Karakteristični morfometrijski parametri značajni za
definisanje geometrijskog/matematičkog modela
BUTNE KOSTI
Doc.dr Stojanka Arsić
4.Sastanak projektnog tima
29.11.2008
Mašinski fakultet Niš
FEMUR / PROKSIMALNI OKRAJAK
Karakteristični morfometrijski parametri značajni za
definisanje geometrijskog/matematičkog modela
Doc.dr Stojanka Arsić
4.Sastanak projektnog tima
29.11.2008
Mašinski fakultet Niš
FEMUR- butna kost
DELOVI
1.GORNJI OKRAJAK
(extremitas proximalis)
2.TELO
( corpus femoris)
3.DONJI OKRAJAK
( ekstremitas distalis)
FEMUR- butna kost
GORNJI OKRAJAK
(extremitas proximalis)
ZGLOBNE POVRŠINE
NA GORNJEM I DONJEM
OKRAJKUFEMURA
ZGLOBNE POVRŠINE
NA GORNJEM
OKRAJKUFEMURA
DA SILVA, V. J.; ODA, J. Y. & SANT'ANA, D. M. G.
Anatomical aspects of the proximal femur of adults brazilians.
Int. J. Morphol., 21(4):303-308, 2003.
The following morphometric measures were made: angle of the femur neck,
1. angle of the femur neck,
2. circumference of the femur head and neck,
3. length of the femur neck and
4. length of the whole bone.
The comparative analysis of the
5. angle of the femur neck between the right and left sides
The comparative analysis of the
5. angle of the femur neck between the right and left
sides of adults demonstrated values similar to
those described in the classic literature for adults
with mean significantly smaller on the right side
(122.5o) than on the left side (125.6o). As for the
length of the femur neck in this study larger
values on the left side (23.5 mm) than on the right
side (22.3 mm) were observed
Angle of the femur neck (ACF):
angle between the neck and the diaphysis, using a goniometer
Fig. 1. Schematic representation of the proximal epiphysis of the
femur demonstrating the reference points for the morphometry of the
angle of the femur neck (ACF)
• Length of the femur (CF): a line was drawn
along the bone from the median point of
the proximal epiphysis to that of the distal
epiphysis.
• - Length of the femur neck (CCF): straightline distance from the base of the greater
trochanter to the inferior region of the head
(Fig. 2).
. Fig2. Schematic representation of the proximal epiphysis of the femur
demonstrating the reference points for the morphometry. CCF length of the
femur neck.
Circumference of the median points of the femur neck and head
Fig. 3. Schematic representation of the proximal epiphysis of the femur
demonstrating the reference points for the morphometry.
CcaF circumference of the femur head.
The articular trochanteric distance
Parameters commonly used
to evaluate proximal femur geometry
Parameters commonly used to evaluate proximal femur
geometry.
A, Neck-shaft angle;
B, Femoral neck axis length or femoral neck length;
Taken from:
Bouxsein M, Karasik D: Bone Geometry and Skeletal
Fragility. Current Osteoporosis Reports. 4(2):49-56.
Current Medicine Group LLC.
The human hip joint. Radiograph of the human proximal femur and acetabulum in
which the two main systems of trabeculae (group 1 and 2) are indicated.
These are traditionally known as the principle tensile and compressive trabeculae
respectively, a questionable nomenclature.
Rudman et al. BioMedical Engineering OnLine 2006 5:12 doi:10.1186/1475-925X-5-12
• Compression or tension? The stress
distribution in the proximal femur
• KE Rudman , RM Aspden and JR
Meakin Department of Orthopaedic
Surgery, University of Aberdeen,
Foresterhill, Aberdeen, AB25 2ZD, UK
• BioMedical Engineering OnLine 2006,
5:12doi:10.1186/1475-925X-5-12
• Mechanically Mediated Bone Adaptation
bone mechanical properties depend significantly on bone tissue structure
Mechanically Mediated Bone Adaptation Theories (1865 - 1920)
Theories of how mechanical stimulus affected bone adaptation begin in earnest
about the time the American Civil War was ending. In 1867, a German anatomist
Von Meyer received a grant from the Prussian government to study skeletal
posture. As part of this grant, Von Meyer studied trabecular orientation in the
proximal femur. While presenting these results at a scientific meeting, a Swiss
engineer named Culmann noticed that Von Meyer's trabecular drawings bore a
striking resemblance to principal stress lines Culmann had determined for a
crane.
The trabecular drawings and crane principal
stress lines
– Diagram of the lines of stress in the upper femur, based upon the
mathematical analysis of the right femur. These result from the
combination of the different kinds of stresses at each point in the femur.
(After Koch.)
– Intensity of the maximum
tensile and compressive
stresses in the upper femur.
Computed for the load of 100
pounds on the right femur.
Corresponds to the upper part
of the previous figure .
(After Koch.)
Diagram of the computed lines of
maximum stress in the normal femur.
The section numbers 2, 4, 6, 8, etc., show the
positions of the transverse sections analyzed.
The amounts of the maximum tensile and
compressive stress at the various sections
are given for a load of 100 pounds on the
femur-head. For the standing position (“at
attention”) these stresses are multiplied by
0.6, for walking by 1.6 and for running by 3.2.
(After Koch.)
FIG. 249– Frontal longitudinal
midsection of left femur. Taken from
the same subject as the one that was
analyzed and shown in Figs. 248 and
250. 4/9 of natural size. (After Koch.)
Forces as much as 6x body weight are transmitted across the hip. The
bone remodels according to the forces applied (Wolff's law) and this is
reflected in the trabecular pattern illustrated above. This is highly relevant
to fracture mechanism and fixation.
The image shows the regions
usually measured on the proximal
femur:
NECK,
TROCHANTERIC, AND
INTER-TROCHANTERIC.
All three together form the "total
hip" - which is not actually the hip
joint at all.
Ignore "Ward's triangle" which is
an unreliable square.
Note that the trochanteric region is
less dense because it has more
trabecular bone. Also, it is critically
important that the cutoff line at the
bottom is in the standard place,
because even one pixel will include
more of the dense bone of the shaft
and make the measurement
inaccurate.
This is an image from Lunar. The newer densitometers include the
total hip, the older ones only the neck and trochanter.
Recommendations for BMD Testing
BMD of the hip can be measured at several
regions, including
the femoral neck,
trochanteric,
intertrochanteric,
Ward's Triangle and/or total hip. With the
large region of interest in the total hip,
measurement errors may be minimized.
However, caution must be used in measuring
Ward's triangle; its small area introduces a
higher possibility of measurement error and
the anatomic site itself may be variably
defined by different manufacturers.27 Unlike
the spine, where cancellous bone is uniformly
distributed and, thus, shows a uniform pattern
of bone loss, the hip shows variable BMD
because different areas of the femur are
composed of different percentages of
cancellous bone, and have different risks of
fracture.28
Result a virtual load testing a femur by using a CT based Finite
Element Method. (Fig. 1)
The result of the stance configuration (left). The predicted fracture
line (red line) located at the femoral neck. The result of the fall
configuration (right). The predicted fracture line appeared at the
femoral trochanteric region. The color bar represents maximum
principal stress.
•
•
•
•
•
The Department of Orthopaedic Surgery, The University
of Tokyo. Graduate School of Information Science and
Technology, The University of Tokyo.
Objects
To develop a non-invasive method for predicting bone
strength.
To develop osteosynthetic devices.
Major Research Projects Orthopedic biomechanics
Bone mechanics
Mechanobiology
External fixation biomechanics
Basic research for metallic materials for osteosynthesis
• Identification of hip fracture patients
from radiographs using Fourier
analysis of the trabecular structure: a
cross-sectional study
• Jennifer S Gregory1 , Alison Stewart2
, Peter E Undrill3 , David M Reid2 and
Richard M Aspden1
Regions of interest. Displays the five
regions of interest,
upper femoral head (UH),
central femoral head (CH),
upper femoral neck (UN),
Ward's triangle area (WA) and the
lower femoral neck (LN) used for
analysis.
Points A to G are determined by the
femoral head and neck and used to
locate the ROIs
. Points A and E mark the femoral
neck width.
Points B, C and D lie at 1/4, 1/2 and
3/4 along this line.
Point F is the centre point of the
femoral head,
point G at 1/2 the radius of the femoral
head at an angle of 45 degrees to the
neck width, 135 degrees to the neck
shaft, shown as a dashed line through
point C.
Gregory et al. BMC Medical Imaging
2004 4:4
•
•
•
•
•
Profile generation.
(A) Shows a typical region of interest (contrast enhanced for visualisation)
showing the trabecular bone structure, in this case aligned approximately
22° to the vertical.
(B) The central section of the FFT (128 × 128 pixels). The horizontal and
vertical axes have been marked with a mid-grey tone to indicate that they
have been excluded from the angle calculation. The bright strip at the centre
(running from top left to bottom right) shows the preferred orientation of the
trabeculae. Angles calculated from the Fourier power spectrum correspond
to the same angles in the spatial domain, rotated by 90°.
(C) The pixels with the maximum values are marked using white squares
for the first 25 spatial frequency values of the Fourier power spectrum. The
median angle, lying 21.8° from the horizontal is shown by a dashed white
line. (D)_The regions used to generate the parallel (shaded black) and
perpendicular (shaded white) profiles, based on the orientation of the
trabecular structure.
Gregory et al. BMC Medical Imaging 2004 4:4 doi:10.1186/1471-2342-4-4
Download authors' original image
Hip Axis Length HAL
• single best predictor of hip fracture is femoral bone density.
But bone density is not the only factor influencing weather or
not a fracture will occur.
• According to engineering principals, strength depends on
• (1) the mechanical properties of the materials,
• (2) the objects geometry and shape, and,
• (3) the loading conditions, in terms of magnitude, rate, and
direction, of force applied to the object.
• If geometry of the hip is related to fracture risk, geometric
measurements might be used together with densitometric
evaluations for a better assessment of hip fracture risk than
might be obtained from just a density measurement alone.
• Prospective studies show that HAL has demonstrated the
ability to predict fractures!1
1. Faulkner K., Advanced Hip Assessment, GE Medical Systems Lunar, July 2001
Key Measurements
Each centimeter (10%) increase
in Hip Axis length (HAL)
increases hip fracture by 5080% depending on the study.
For short term prediction of hip
fracture (within 2 years), HAL
was shown to predict hip
fractures independent of BMD.1
1. Faulkner K., Advanced Hip Assessment, GE Medical Systems Lunar, July 2001
DualFemur
With the DualFemur option, both femora are automatically scanned in one
seamless acquisition without repositioning the patient. As such DualFemur
allows you to assess the density of the critical hip region, including
identification of the weakest side increasing confidence in your treatment
decisions. In addition, the trending function enables seamless follow-up of
change over time.
• The DualFemur application atomically
measures, and averages, both the left and right
femora in one measurement sequence.
• This procedure promises to improve diagnostic
accuracy by identifying the femur with the lowest
density. An equally important benefit is a 30%
decrease in precision error, which improves
sensitivity for monitoring response at the femur
itself!
•
. Faulkner K., Advanced Hip Assessment, GE
Medical Systems Lunar, July 2001
Upper Neck Region
The Upper Neck Region is
comprised of the upper half of
the standard Neck region. This
new region is highly sensitive
to bone loss and is can be
used as an early predictor of
trochanteric and neck
fractures.1
1. Faulkner K., Advanced Hip Assessment, GE Medical Systems Lunar, July 2001
• The upper portion of the femoral neck has been reported
to be a sensitive predictor of neck fractures. Studies
have demonstrated that femoral fractures are usually
initiated in the upper neck region. The thickness and
porosity of the bone in the upper neck region is believed
to be critical to maintaining femoral strength. The upper
neck demonstrates a more rapid age related decline
than the standard femoral neck region, suggesting it may
provide some advantage for early detection of
osteoporosis.1
1. Faulkner K., Advanced Hip Assessment, GE Medical Systems Lunar, July 2001
The femoral neck torsion angle (FNTA) is the angle between the axis of
the femoral neck (cervical plane) and the coronal plane of the femoral
condyles (condylar plane). If the neck is oriented forward with respect to the
condylar plane, it is referred to as anteversion (positive FNTA).
Radiograph of the hip region:
Identify the following on
a radiograph of the hip region:
•ilium
•ischium
•pubis
•pubic symphysis
•sacroiliac joint
•acetabular lip
•head of femur
•neck of femur
•greater trochanter
•lesser trochanter
The Functional Fit
• The ITST Intramedullary Nail System is
designed to treat unstable, comminuted,
proximal fractures of the femur, specifically, the
intertrochanteric and subtrochanteric regions.
The ITST design is truly versatile in offering the
combined features of intramedullary nail and hip
screw systems.
True Anatomic Design
Proximal design features an
anatomic 5° Lateral Bend,
which allows for the less
invasive trochanteric starting
point to be utilized.
Inserted into the femoral
head at 130°, the most
common angle used in
gliding nails.
15° anteversion of the
proximal holes for easier
passage of the nail down the
femoral canal, and simpler
distal freehand targeting.
Range of distal diameters
accommodates anatomic fit.
Natural Proximal Geometry
• Construct is a high strength stainless steel alloy, 22-135, which allows the implant more design freedom, while
maintaining adequate implant strength.
• Proximal geometry features a bone conserving diameter
of 16.5mm.
• Accommodates an 11mm Lag Screw, providing a high
level of proximal bone-implant interface.
• The height of the proximal nail diameter combined with a
short transition region allows for easy insertion of the
Lag Screw across the femoral neck, without the concern
of the nail sitting too proud or too deep in the bone.
• True Anatomic Design
Implant geometry
Implant
geometry
Caracterisation of the risk of dislocation of a prosthetic configuration by the distance
AB
- Dislocation occurs when the head moves from point A to point B
- The risk diminished when AB increases
- AB is determined by, size of the head, depth of the cup, degree of incline
- AB characterises a system in terms of risk of dislocation
- AB = R head x √ 2 x (1 – cosα )
-By Massé and Wagner
Implant geometry
• When we look at the external geometry of the today’s
implant, it is a press fit hemisphere which is extended in
the equatorial region cylindrically by 3mm (figure 7).The
pole is slightly flattened by removing 0.5mm of metal in
order to optimise impaction and enhance the press fit.
The equatorial press fit is augmented by an even band of
slightly raised ridges which ensure primary stability.
These ridges form a very even macrostructure around
the equatorial rim, but the geometry is in keeping with
Gilles Bousquets three point fixation concept. The press
fit is optimised at the levels of the ilium, ischium and
pubis due to the macrostructure rides being more raised
at these points (figure 7).
Figure 7: Primary fixation mode of the NOVAE cups
-External geometry
-1/2 sphere
-+3mm equator
-Pole flattened by 0.5mm
-+ Zone of equatorial press fit
- Details of concept
• If the cup comes across as being cylindro –
spherical, its geometry is more complex. It is in
fact a cup with a raised superior portion.
• The geometry of todays cup in effect comes
from the original geometry which was chamfered
in the lower (inferior) zone and extended in the
upper (superior) zone, which resulted in an 8mm
cap extending from the equator of the
hemisphere
Figure 8: Evolution of the geometry of the cup
-1/2 sphere
-Cap
-Section through cylinder and ½ sphere
-Novae 1: previous generation
-Superior point
-Inferior point
-Elimination of lateral edges (protuberances)
-Novae 1 => Novae Evolution
Fig 3: Measurement of diameter of femoral head
Method of measurement of
diameter of acetabulam
Fig 1: Method of measurement of
depth of acetabulam
Osteotomy
Deformable Lower Extremity Model
•
graphics-based model of the human lower extremity with a
"deformable" femur.
• This model characterizes the geometry of the pelvis, femur, and
proximal tibia, the kinematics of the hip and tibiofemoral joints, and
the paths of the medial hamstrings, iliopsoas, and adductor muscles
for an average-sized adult male.
• The femur of our deformable model can be altered to represent
anteversion angles of 0-60°, neck-shaft angles of 110-150°, and/or
neck lengths of 35-60 mm. The lesser trochanter torsion angle of the
model can be adjusted by as much as 30° anteriorly or 10°
posteriorly. Hence, this model enables rapid and accurate estimation
of muscle-tendon lengths and moment arms for individuals with a
wide range of movement abnormalities and femoral deformities.
"deformable" femur.
Deformable model in action. We can deform the femur of our generic model (left,
shaded bone) to resemble the deformed femurs of children with cerebral palsy
(wireframe bone) by increasing its femoral anteversion angle (middle) and its neckshaft angle (right).
• Associated Publications
• Arnold and Delp. Rotational moment arms of the
hamstrings and adductors vary with femoral
geometry and limb position: implications for the
treatment of internally-rotated gait. Journal of
Biomechanics, 2001. (Download PDF)
• Arnold, Blemker, and Delp. Evaluation of a
deformable musculoskeletal model for
estimating muscle-tendon lengths during crouch
gait. Annals of Biomedical Engineeering, 2001.
(Download PDF)
• A new value of proximal femur geometry to
evaluate hip fracture risk: true moment arm.
• Ulusoy H, Bilgici A, Kuru O, Sarica N, Arslan
S, Erkorkmaz U.
• Hip Int. 2008 Apr-Jun;18(2):101-7.
• This study was undertaken to determine the
influence of proximal femur geometry on hip
fracture risk independent of bone mineral
density
Glinkowski Wojciech; Ciszek Bogdan
Antomy of the Proximal Femur -geometry and architecture. Morphologic
investigation and literature review.
Ortopedia,traumatologia,rehabilitacja 2002;4(2):200-8
• Material and methods. To analyze morphology and endosteal
anatomy of the proximal ends of the femur of 40 cadaver femora
were x-rayed, dissected and measured. Various variables including
trabecular pattern, calcar size, and cortical bone were measured
and correlated. Observations were compared to literature concerns
the various aspects of anatomy of the proximal femur. <br />
Results. One must recognize that much of the information that we
gather in every day practice is two dimensional, namely, x-rays of
the hip. Morphological data with three-dimensional perspective
demonstrate internal architecture of proximal femur including calcar
femorale. Authors pointed out lower values of neck shaft angle than
observed in other examined populations.<br /> Conclusions. They
found that topographic and angular position of calcar femorale
depends on anteversion angle. Shadow of the calcar on X-ray of the
femur in Lauenstein's view may become invisible in some cases
what is correlated to its real dimension. Calcar femorale as a
anatomical structure has no strict topographic coincidence with
"calcar resorption" observed in some total hip replacements.
Differences in proximal femur geometry distinguish vertebral from
femoral neck fractures in osteoporotic women
Authors: Gnudi,; Malavolta,; Testi,; Viceconti,
British Journal of Radiology, Volume 77, Number 915, March 2004 , pp. 219-223(5)
• Women with femoral neck fractures had
longer HAL, wider FND and larger NSA
than controls, whereas there were no
statistically significant differences in PFG
between women with spine fractures and
controls. Logistic regression showed HAL
and NSA could predict the risk of femoral
neck but not vertebral fracture. These data
indicate specificity of some PFG
parameters for hip fracture risk.
FEMUR / DISTALNI OKRAJAK
Karakteristični morfometrijski parametri značajni za
definisanje geometrijskog/matematičkog modela
Doc.dr Stojanka Arsić
4.Sastanak projektnog tima
29.11.2008
Mašinski fakultet Niš
FEMUR- butna kost
DELOVI
1.GORNJI OKRAJAK
(extremitas proximalis)
2.TELO
( corpus femoris)
3.DONJI OKRAJAK
( ekstremitas distalis)
FEMUR- butna kost
DONJI OKRAJAK
( ekstremitas distalis)
Fig. 1 A true lateral preoperative radiograph demonstrates the four
measurements recorded in each case: anteroposterior diameter of the femur
10 cm from the joint line, maximum length of the patella, posterior condylar
offset, and anterior femoral offset.
Fig. 2 A true lateral postoperative radiograph demonstrates seven of the
eight measurements recorded in each case: the same four measurements
recorded preoperatively plus femoral component flexion relative to the
anterior cortex, notching of the anterior cortex, and posterior slope of the
tibial component. The eighth postoperative measurement was medial or
lateral overhang of the femoral component at the distal joint line taken on
the standing anteroposterior view.
The unisex femoral components did not match the native female anatomy.
Surgical techniques
Anatomy of the distal femur
On the lateral view the shaft is aligned with the anterior half of the lateral condyle.
The distal femur is trapezoidal
Anterior surface slopes downward from lateral to medial,
Lateral wall inclines 10 degrees
Medial wall inclines 25 degrees.
knee joint is parallel to the ground
anatomic axis (the angle between the shaft of the femur and the knee joint)
has a valgus angulation of 9 degrees (range, 7 to 11 degrees)
Approaches
Radiolucent table, small sand bag under ipsilateral hip, free drape leg.
If nailing use triangle/ bolster under knee to flex slightly(30-40
degrees), allows easier entry.
Lateral approach most commonly used exposure. Suitable for all
fractures except with fracture limited to medial femoral condyle.
Lateral skin incision centred over lateral condyle across joint then curve
gently anterior to end just lateral to tibial tuberosity
Through iliotibial band, through joint capsule and synovium exposing
lateral femoral condyle (inferior geniculate art.). Don't cut lateral
meniscus.
Elevate Vastus lateralis from intermuscular septum, ligating perforators.
Exposing lateral femoral condyle.
More access
Add tibial tuberosity osteotomy ( pre drill hole). Detach fat pad from tibia
and reflect Quadriceps mechanism.
Alternative - Z-shaped tenotomy of the infrapatellar tendon. If used protect
with wire band 12 weeks
Anterior approach
Anterolateral skin incision
Lateral parapatellar arthrotomy
Vastus lateralis is elevated off the lateral femoral cortex. Anterior skin
incision allows better visualisation of medial femoral condyle.
Medial Approach (fracture limited to medial condyle, severly comminuted
needing double plating)
Straight medial skin incision over the thigh distally over the medial condyle
anterior to the adductor tubercle.
Incise deep fascia in line with the skin incision,
Elevate vastus medialis from the adductor magnus (medial geniculate
artery)
Medial patellar retinaculum, joint capsule, and synovium. Stay anterior to
medial collateral ligament and avoid medial meniscus.
Beware femoral art. and V.
Anterolateral approach ( complex intra articular fractures)
As for TKR midline and medial parapatella, sublux patella laterally.
Offers excellent exposure of articular surface.
• Implants
• For all first step is exposure and
reconstruction of articular surface with lag
screws if needed. Placing lag screws away
from entry points of individual implants.
• 95 Degree Blade plate
• Mark site of entry of blade plate
• Implants
• For all first step is exposure and
reconstruction of articular surface with lag
screws if needed. Placing lag screws away
from entry points of individual implants.
• 95 Degree Blade plate
• Mark site of entry of blade plate
Mark site of entry of blade plate
1.5-2 cm from distal
articular surface centered
on a point in the middle of
the anterior 1/2 of the
lateral condyle.
Mark
trajectory
Frontalplane - parallel to the joint
surface.
Transverse plane - between the
patellar groove anteriorly and the
intercondylar notch posteriorly.
Place K wire along the distal
articular surface, and another
across the anterior surface of the
femur, over the patellar groove.
Insert third K-wire into the lateral
femoral condyle distal to the marked
blade entry site
Parallel to the distal K-wire in the
frontal plane and parallel to the
anterior K-wire in the transverse
plane.
Check position of third k wire on
image intensifier and use third wire
to guide central drill hole
• Finally control the rotational position of the blade in the coronal
plane (i.e., flexion and extension) should be such that the plate will
align with the femoral shaft. Think of this when drilling top and
bottom of 3 drill holes. Then join 3 holes with seating chisel.
• Remember the trapezoidal cross section of the femur, therefore
measure the most anterior distance in the channel. Use of
radiographs or the depth of the posterior end of the slot for the
determination of blade length will result in medial protrusion of the
blade. Ensure 8 cortices proximal fixation to the shaft
• NB A blade not parallel to the joint will induce a varus or valgus
deformity
• Because of the trapezoidal shape of the distal femur, a posterior
blade entry point will result in a medialization of the distal segment,
along with increasing the risk of notch penetration.
• A mal-rotation of the blade will result in flexion or extension
deformity
Dynamic Condylar Screw
•
•
•
The plate-barrel (screw) angle is 95 degrees, as in the blade plate.
Once the screw is placed, flexion and extension can still be adjusted, unlike
the blade plate.
It does not afford good rotational control unless a screw from the side plate
engages the distal fragment viz implications for distal fractures.
Dynamic Condylar
Screw
Insert guide wire as for centre of blade plate,
slightly more proximal (2 cm from the joint surface
at the junction of the anterior 1/3rd and posterior
2/3rds of the longest AP dimension of the lateral
femoral condyle or in the middle of the anterior
half of the lateral femoral condyle) Trajectory as
for blade plate.
Advance guide wire to medial cortex (remember
trapezoidal shape), measure depth. Ream and
place screw 5 to10 mm shorter than measured to
avoid soft tissue irritation
Insert screw as for DHS remember alignment of
handle to align side plate.
Insert at least one screw from side plate into distal
fragment to control flexion/ extension
Check length and rotation, then attach side plate
with at least 8 proximal cortices.
The above can be done by a mini invasive technique as described by Russell
using a femoral distractor placed on the lateral side of the leg with two 5-mm
Schanz pins.
Retrograde Locked Intramedullary Nails
(including supracondylar nail)
•Medial parapatella approach or minimally invasive split patella tendon.
•
Entry point in line with
intramedullary canal, centre
intercondylar notch anterior to
origin of PCL on femur
Locking configuration depends on
make of nail. At least two distal
screws to control flexion and
extension.
Reamed or unreamed
If intercodylar split ream opening
to avoid seperating condyles.
Russell, George V. Jr. MD. Smith, Douglas G. MD. Minimally Invasive
Treatment of Distal Femur Fractures: Report of a Technique. Journal of
Trauma-Injury Infection & Critical Care. 47(4):799, October 1999
• Comparison of the generic femur model
and a patient-specific femur with shorter
statue and a mild bowing deformity
derived from the generic model using
parametric scaling technique.
• Chao et al. Journal of Orthopaedic
Surgery and Research 2007
2:2 doi:10.1186/1749-799X-2-2
Download authors' original image
The Dynamic Knee Simulator used to
study knee flexion and joint loading under
simulated squatting activity. Independent
loads are applied to the simulated hip
joint, the medial and lateral hamstrings
tendons and the quadriceps tendon using
hydraulic actuators. The tendons are
secured to the loading actuators using
cryo-clamps. The MTS Model 790.00
TestStar™ II Control System software
(MTS Systems Corporation, Eden Prairie,
MN) was used to control and monitor all
motion and loading conditions.
Chao et al. Journal of Orthopaedic
Surgery and Research 2007
2:2 doi:10.1186/1749-799X-2-2
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Ortop. bras. vol.12 no.3
São Paulo July/Sept. 2004
Morphometric study of the femoral intercondylar notch of knees
with and without injuries of anterior cruciate ligament (A.C.L.),
by the use of software in digitalized radiographic images
Rita di Cássia de Oliveira AngeloI; Sílvia Regina Arruda de
MoraesII; Luciano Carvalho Suruagy III; TetsuoTashiroIV; Helena
Medeiros CostaV
IMaster Graduate in Morphology at Anatomy Department of UFPE
IIAssociated Professor in Morphology of Anatomy Department
of UFPE
IIIDoctor of Arthroscopy Service and Knee Surgery of
CMH/PMPE
IVAssistant Professor of Physical Education Department of
UFPE
VPhysiotherapist
Figure 2.12. View of the distal femur. This view demonstrates
the slightly thinner medial femoral condyle which also has
more acute inclination than the lateral. The anterior
prominence of the trochlear flare on the lateral aspect
demonstrates an obvious, increased anterior/posterior
dimension for the lateral femoral condyle. (Reprinted with
permission from I. A. Kapandji: The Physiology of the Joints,
Vol. Il, Churchill LivingstoneNew York, 1970(5).)
Figure 2.13. (A) Diagrammatic sagittal section of the medial femoral
condyle showing the radii of curvature. Anterior-posterior dimension
is smaller than that shown in B, which represents the lateral femoral
condyle. (B) Lateral femoral condyle showing radii and centers of
curvature and longer anterior-posterior dimension. The overall forms
of each femoral condyle is similar; however, the radii of curvature
and general dimensions are dissimilar. (Reprinted with permission
from I. A. Kapandji: The Physiology of the Joints, VoL II, Churchill
Livingstone, New York, 1970(5).)
• 3-D Morphology of the Distal Femur
Viewed in Virtual Reality
• (AAOS 2001 annual meeting - Scientific
Exhibit No. SE28)
Donald G Eckhoff, MD, Denver, CO
Thomas F Dwyer, MD, Denver, CO
Joel M Bach, PhD, Aurora, CO
Victor M Spitzer, PhD, Aurora, CO
Karl D Reinig, PhD, Aurora, CO
• The morphologic shape of the distal femur dictates the
shape, orientation and kinematics of prosthetic
replacement in total knee arthroplasty.
• Traditional prosthetic designs incorporate symmetric
femoral condyles with a centered trochlear groove.
Traditional surgical techniques center the femoral
component to the distal femur and position it relative to
variable bone landmarks. However, failure patterns
documented in retrieval studies13,15, case series 9, and
kinematic studies demonstrate how traditional design
and surgical technique reflect a poor understanding of
distal femoral morphology and knee kinematics.
• It has been shown that the flexion/extension (F/E) axis of the knee is
fixed within the femur and that the articular surfaces of the condyles
are circular in profile11,12. Ligament length patterns are significantly
altered by abnormal axis alignment when using a hinged knee brace
14. It is expected that a malaligned femoral component would have
the same effect in TKA.
• The purpose of this exhibit is to demonstrate with conventional
images and with interactive animations in virtual reality the threedimensional shape of the naturally asymmetric distal femur,
illustrating the sulcus axis of the trochlear groove and flexion axis of
the condyles relative to conventional axes (mechanical, anatomic,
epicondylar & posterior condylar axes). Correlations between the
morphologically determined rotation axes and experimentally
determined kinematic axes are illustrated.
• Methods:
Eighty-five mummified cadaveric knees (fig. 1 below left)
were measured with a stereotactic micrometer (fig. 2
below center). The location and orientation of the sulcus
were obtained by repeated horizontal passes of the
stereotactic stylus over the distal femur beginning at the
top of the articular surface and progressing down to the
intercondylar notch (fig.3 below right). With each
horizontal pass, the lowest depression of the trochlea
(sulcus) was identified by the stereotactic stylus and the
coordinates were recorded. After each horizontal pass,
the stereotactic device was lowered by 2 mm to provide
sequential horizontal tracings.
The stereotactic micrometer, originally designed to localize intra-cranial lesions in
neurosurgery, was modified to hold cadaveric femora for topographical mapping of
the condyles and trochlear groove (fig.2 above center).
The stylus of the micrometer moves horizontally and vertically in millimeter
increments to allow measures of depth in millimeters of the articular surface of the
condyles and trochlea in the horizontal plane
The distal femora and
proximal tibial computed
tomography "cuts" were
superimposed to measure
relative translation and
rotation. The proximal and
distal femoral cuts were
superimposed to measure
femoral version (fig. 13
above right)
34 patients (34 knees) with anterior
knee pain were measured by
computed tomography and compared
to 34 age matched normal knees (fig.
11 above right)
• The morphologic and biomechanical
characteristics of the knee defined in these
studies were measured in cyberspace and
illustrated with a computer visualization program
as an Interactive Anatomic Animation (IAA) in
three additional cadaveric specimens. These
three cadaveric knees were sectioned with CT
into 0.1-1.0 mm slices, digitized, and
reconstructed in virtual space (fig. 14-16 below).
Computer generated cylinders were
"grown" within the confines of the articular
surface of the distal femur to confirm and
illustrate the cylindrical geometry of the
condyles as well as demonstrate the
position of the cylindrical axis relative to
conventional axes (mechanical, anatomic,
epicondylar & posterior condylar axes).
(fig. 17 below)
• The sulcus of the trochlear groove lies
lateral to the mid-plane and is oriented
between the mechanical and anatomic
axes of the femur (fig. 18 below left,19
below right).
sulcus of the trochlear groove
lies lateral to the mid-plane and
is oriented between the
mechanical and anatomic axes
of the femur
• The sulcus (lowest point) is a near-linear
depression in the trochlear groove that lies
lateral to the midplane defined as the plane
perpendicular to the posterior condylar axis. (fig.
18 above left)
The sulcus is oriented between the traditional
mechanical axis (line joining center of femoral
head and center of knee) and
• anatomic axis (center of femoral shaft). (fig. 19
above right)
sulcus of the trochlear groove
lies lateral to the mid-plane and
is oriented between the
mechanical and anatomic axes
of the femur
• The cross-sectional center of the femur lies
medial and anterior to the cross-sectional center
of the tibia (fig.20 below).
• The cross-sectional centers of the distal femur
and proximal tibia are not superimposed, but are
translated 4+6 mm anteroposterior and 5+4 mm
mediolateral in both normal and pathologic
knees (ostheoarthritic and anterior knee pain).
(fig. 20 above)
The cross-sectional center of the femur lies medial and anterior to the crosssectional center of the tibia (fig.20 below).
The cross-sectional centers of the distal femur and proximal tibia are not
superimposed, but are translated 4+6 mm anteroposterior and 5+4 mm
mediolateral in both normal and pathologic knees (ostheoarthritic and anterior
knee pain). (fig. 20 above)
One view of the Interactive
Animation of the distal femur
demonstrated in this exhibit
illustrates the 3-D relationship
between the epicondylar axis
(green line) and the
"cylindrical axis" (red line)
defined by the center of the
cylinders which most closely
reproduce the geometry of the
condyles. (fig. 25 above)
• This study carefully documents the asymmetric
morphologic features of the distal femur and correlates
these features with the kinematics of the knee.
• The location and orientation of the femoral sulcus is
lateral to the midplane between the femoral condyles
and oriented between the anatomic and mechanical
axes of the femur.
• The center of the femur in cross-section is off-set,
medial and anterior, to the center of the tibia.
• These asymmetric, off-set morphologic features of distal
femur should be incorporated in the design (fig. 26
below) and positioning of prosthetic replacements in the
knee.
•These asymmetric, off-set morphologic features of distal femur should be
incorporated in the design (fig. 26 below) and positioning of prosthetic replacements
in the knee.
• This study further documents
• the asymmetric cylindrical shape of the condyles and
• establishes the cylindrical axis of rotation of the condyles about
which the tibia rotates.
• The measured kinematic data supports the morphologic findings for
a fixed, cylindrical flexion/extension axis of rotation.
• This study provides kinematic and morphologic validation for a
single cylindrical flexion/extension axis of the knee.
• This scientific exhibit is the first to illustrate these observations in 3D stereo using interactive animations and virtual reality.
• (This Project has been funded in whole or in part with Federal funds
from the National Library of Medicine under Contract No. N01-LM-03507.)
Figure 3. Centrally located points used in measures of alignment (as modified9). The
centers of the femoral intercondylar notch and tibial spines, respectively, denote the
locations of the femoral axis distally and the tibial axis proximally in our recommended
approach.
• PRINCIPLES AND MEASUREMENTS OF
ALIGNMENT
• From the anatomical and functional perspective,
the orientation of the femur and tibia at the knee
is best described in terms of the bones'
mechanical axes. The orientation of these axes
reflects alignment in stance, which may be
neutral, varus (bowlegged), or valgus (knockkneed) (Figure 1).
Figure 1. Common frontal plane lower limb alignment patterns.
A. Varus alignment: knee center is lateral to the LBA (HKA is negative).
B. Neutral alignment: knee center is located on the LBA (HKA = 0°); femoral and tibial
mechanical axes are colinear.
C. Valgus alignment: knee center is medial to the LBA (HKA is positive).
LBA: load-bearing axis, HKA: hip-knee-ankle angle, FM: femoral mechanical axis, TM:
tibial mechanical axis.
• The mechanical axis of the femur (FM) is located as a line from the
center of the femoral head running distally to the mid-condylar point
between the cruciate ligaments11.
• In the case of the tibia, the mechanical axis (TM) is a line from the
center of the tibial plateau (interspinous intercruciate midpoint)
extending distally to the center of the tibial plafond12 (Figure 2).
• The angle between these 2 axes is the hip-knee-ankle (HKA)
angle1,13.
• In the neutrally aligned limb the HKA angle approaches 180°. At this
point FM and TM are colinear, pass through the knee center, and are
coincident with the load-bearing axis, which is the line of ground
reaction force passing from the ankle to the hip1,13 (Figure 1B).
• In varus the knee center is lateral to the load-bearing axis (Figure
1A), whereas in valgus the knee center is displaced medially13,14
(Figure 1C).
• As a convention the HKA angle may be expressed as its angular
deviation from 180° (i.e., HKA = 0° in neutral alignment). Varus
deviations are negative and valgus deviations are positive. Our
choice of varus as a negative value and valgus as positive was based
on the general observations of a more serious problem of loading and
damage in the varus knee.
Figure 2. Frontal plane angles in a limb with varus
alignment. LBA: load-bearing axis,
CH: condylar-hip angle, the angle of the femoral
condylar tangent with respect to the femoral
mechanical axis; varus negative, valgus positive. For
the HKA measured as deviations from 90°.
PA: plateau-ankle angle, the angle between the tibial
margin tangent and the tibial mechanical axis; varus
negative, valgus positive. For the HKA measured as
deviations from 90°.
CP: condylar-plateau angle: the angle between the
femoral and tibial joint surface tangents; narrowing
medially, negative, and laterally positive. HKA. Hipknee-ankle angle: the angle between the femoral and
tibial mechanical axes; varus negative, valgus
positive. Measured as 180° equaling zero.
FM: femoral mechanical axis,
TM: tibial mechanical axis,
FM-FS: angle between the femoral mechanical axis
and the femoral shaft axis.
• Limb alignment (HKA) depends both on long bone
geometry and on the geometry of the articulating surfaces
of the femur and tibia1. In the course of knee arthritis,
changes of alignment are usually ascribed to changes in
the articulating geometry. Typically, focal erosion in the
medial compartment leads to narrowing that, under load,
displaces the knee center laterally (varus deformity;
Figure 1A). Similarly, narrowing of the lateral
compartment imparts medial knee displacement (valgus
deformity; Figure 1C). But, on occasion, deformity of the
femur and/or tibia also influences alignment. To
understand the basis for alignment (and change thereof in
the course of disease) it is crucial to be able to measure
and document articular surface relationships and define
limb bone morphology. Based on simple geometric
analysis the following elements usefully define the
geometry of the tibial and femoral surfaces and the angle
between them when loaded in stance1,13 (Figure 2).
• 1.Condylar-hip (CH): the angle of the femoral
condylar tangent with respect to the FM axis;
• 2. Plateau-ankle (PA): the angle between the tibial
margin tangent and the TM axis;
• 3. Condylar-plateau (CP): the angle between the
femoral and tibial joint surface tangents.
• Since HKA is expressed as degrees of deviation
from 180°, CH and PA angles are expressed as
degrees of deviation from 90°, negative for varus
and positive for valgus. A joint space angle (CP)
that narrows medially is designated varus (–) and
laterally valgus (+). When these conventions are
observed, the following relationship applies1,13:
• HKA = CH + PA + CP
Figure 3. Centrally located points used in measures of alignment (as modified9). The
centers of the femoral intercondylar notch and tibial spines, respectively, denote the
locations of the femoral axis distally and the tibial axis proximally in our recommended
approach.
Tensegrity Knee Construction
. Tensegrity Knee Saddle Joint
Two modified expanded octahedrons rotated 90 degrees to each other axially shows
a remarkably close fit to the geometry of the knee.
Tensegrity Knee Construction
In addition the patella is a
tetrahedral shaped bone that
nests in a gap between the
femur and tibia, its position
maintained by another saddle
tension sling between the
condyles of the femur. For the
purposes of this simplified
model the fibula is considered
part of the tensegrity of the tibia.
Method of restructuring bone
Document Type and Number:
United States Patent 6719793
The method includes providing an implant
structure having a calcium phosphate
component, and stabilizing the implant adjacent
the healthy bone until tissue can recover, bond to
the implant and support the normal required
loading.
The implant structure provides morphological
continuity and anatomical contact between the
implant body and the adjacent healthy bone.
The method further includes providing for
physiological processes to maintain a healthy
junction between the implant and the healthy
bone.
The method further includes controlling, guiding
and directing the bone reconstruction process in
surgical situations where healthy recovery would
not otherwise occur.
• 1.A method of incorporating a prosthetic device into the skeletal
structure of a human or animal for inducing bone repair and stabilizing a
first and a second portion of damaged bone, comprising the steps of:
providing an osteoceramic cylinder adapted to tightly fit into the
intramedullary cavity of the damaged bone; positioning the osteoceramic
cylinder inside the intramedullary cavities of the first and the second
portions of damaged bone; and stabilizing the osteoceramic cylinder
relative to the first and second portions of damaged bone.
2. The method of claim 1, wherein said step of stabilizing the
osteoceramic cylinder further comprises positioning osteoceramic
spacers on the outer surface of the osteoceramic cylinder.
3. The method of claim 1, wherein said step of stabilizing the
osteoceramic cylinder further comprises connecting the osteoceramic
cylinder to at least one of the first and second portions of damaged bone
with one or more bone attachment means.
4. The method of claim 1, wherein the animal is an avian and the
cylinder is hollow.
• FIELD OF THE INVENTION
• This invention relates to a method of
producing restructured bone, and more
particularly to a method causing bone to
bond to an implant containing a calcium
phosphate component, and a method to
control the restructuring of bone through
the use of an implant containing calcium
phosphate.
• Industrial Bioengineering
Coordinator: Prof. Franco Maria
Montevecchi
•
• ENGINEERING IN SURGERY
• Structural topology optimization methodologies
applied to the study of boundary conditions in
physiological femur and pelvis
• The results obtained by structural analysis of
hip arthroplasty models strongly depend on the
correctness of the boundary conditions applied to the
numerical model.
• Structural topology optimization methodologies based on
optimality criteria can be used to identify the most
meaningful loading conditions and, for each of them, the
correct set of applied forces able to justify the layout of
the bone tissue of physiological skeletal element.
Examine the radiograph of
the knee in a couple of views and
identify the:
•femur
•medial condyle
•lateral condyle
•patella
•tibia
•medial condyle
•lateral condyle
•intercondylar eminence
•head of fibula
•neck of fibula
Examine the radiograph of
the knee in a couple of views and
identify the:
•femur
•medial condyle
•lateral condyle
•patella
•tibia
•medial condyle
•lateral condyle
•intercondylar eminence
•head of fibula
•neck of fibula
ENGINEERING IN
ANATOMY AND SURGERY
Hvala na pažnji !!!
Hvala na pažnji !!!