Transcript Folie 1 - M.I.T. Italia s.r.l.

The Femoral neck screw -
prosthesis type Spiron
Biomechanical essentials and studies
First 12 years processes
Mülheim a.d. Ruhr, 12.04.2013
B. Birkenhauer
Stiftungsklinikum Mittelrhein, Location Boppard
Content
• The development of Spiron-Prosthesis
• Biomechanical backgrounds
• Clinical results and studies
•
-12-years processes
- Figuring of incorrect implatations
- Prvention of OP-fails
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Prosthesis design
• Self cutting conical (proximal
cylindrical) Screw
• Rotationsproof design
• No modular concept
• No Left- / Right-variants
• Bonit-coated, rough blasetd
titanium alloy for cementless
fixation
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Conceptional development
„Mother“
„Father“
„Child“
DSP nach Huggler u. Jacob,
Bild: Sulzer Orthopedics
Problem of the DSP: often „long suffering period“ of the pateints, lug pain (???),
Suspicion: too low Osseointegrationsurface
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Pedicalscrew priciple
• Proximal-cortical and
distal and distal
spongiose anchorage by
conical screw body
• Verified good load
distribution even with
strength components
vertical to the implant
axis
ill.: Allopro. Allospine posterior, technichal information biomechanical
investigations. Sulzer Medica. 1999: 3
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Load distribution at the conical screw
On a conical base body
the vertical effective load
will transfered
consistentto the implant
=> Prevention of punctual
bear maximation
ill.: Allopro. Allospine posterior, technichal information biomechanical investigations.
Sulzer Medica. 1999: 2
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Osteological advantages I
• Thread causes an up to
30% Surface
enlargement
(Osseointegrationssurfac
e) as compared to a
conventional cementless
stem prosthesis
• Thread = „bone inductor“
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Osteological advantages II
1. Surface enlargement
(Osseointegrationsurface) by Threaded
sructure
2. Bone induction on protuding prosthesisstructures using the example of
revisionsstem SL on Wagner
Histolog. Pictures used from: Schenk, Wehrli: Zur Reaktion des
Knochens auf eine zementfreie SL-Femur-Revisionsprothese,
Orthopäde (1989)
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Change of the femoral x-raymorphology
by the Spiron-prosthesis
1 year postoperative
1 year postoperative
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Application of force of femoral neck prostehses
Pressure trajectories
Extension trajectories
Sek. Pressure trajectories
Prosthesis as „capstone“
of the trajectories
Pictures: Permedica, JUST-Prothese
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Clinical results
•
•
•
First implantation 08.02.2001
Harris-Hip-Score (HHS) präop. 51
(24-76), n = 51 and increased
after one year to HHS1: 94 (86100), n = 33 on 30 Patients
B. Birkenhauer, H. Kistmacher, J.
Ries, Zementfreie
Schenkelhalsschraubenprothese Typ
Spiron, Konzeption und erste
klinische Ergebnisse, Der Orthopäde,
11/2004,
1259-1266
1 year postop.
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Followup of the implantations 2001-2003
Running followup of the patients with minimum 10 years-process
• n = 48
• substract out (censored) loss: 3
• 2 cases of death, 1 periprothetic Fractures after fall
• Not censored loss: 4
• 2 aseptic early loosening (Implantation fail)
• 2 Early infects (1 Immunsuppr. Patient)
• Precental survival rate after 10(-12) years: 91,2%
• Running evaluation by „HipDo-patient interview sheet“
for assessment of the result quality after min. 10 years with good to very
well long term evaluation of patients
• For Comparison: SP2-survival rate after10(-13) years: 93 %
(Lubinus, P.: Die SP2-Schaft Endoprothese, Frankfurter Orthopädie Symposium, November 2005)
* Copyright: Orthopädische Klinik Dortmund, K. Buckup
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The „disillusionment“
Abstract out of the
A) Australian Hipprothesesregister 2011
Statement
Both register shows that cementless
endoprostheses in younger patient
have worse survival rates than in
older patients
Reason: higher stress!
B) schwedish Hipprothesesregister 2010
Furthermore it‘s interesting that cemented
supplies shows a very good
success!
Ergo: If there is now revision problem,
(older patients) a cemented
implantation is a very welel working
supply
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X-ray processes particularly cases: case 1 (2001)
Statement:
Bone under the collar can resorb several
milimeters without consequences, this
meets also with the calculations
2002
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2004
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2009
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X-ray processes particularly cases: case 2 (2001)
statement:
Femoral neck was damaged.
Cerclage. No consequences
2004
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X-ray processes standard cases: case 3 (2001)
Statement:
Picture proves, no negative bone rebuilding
like with longer prostheses
This meets also with the calculations
2005
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2012
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Example of a early loosending at varus and lateral contact
Statement: Avoid Lateral Contact
If it still appears already intraoperative
change to standard stem
1 Months
5 Months
7 Months
1 year
before Revison
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Example for Varus without lateral contact of the prosthesis
1 y post op
2 year post op
Varus-Position without lateral cortical contact operated permanent
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Example: Septic Early loosening (2002)
Pat. under Immunosuppression with rheumatoid
arthritis with left sided early infect
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What are the central statements?
•
Contact the lateral Spiron should be avoided: - too shallow angle with lateral contact is always wrong - but too
steep angle with lateral contact works (But not recommended!)
•
Don't choose Spiron too thin; Spiron length is not so critical. There Spiron is much to suggest that it is good if the
Spiron still has some distance to the opposite cortex.
•
If loosening were observed, this was in the first 2 years. No loosening at 2 years post-op
•
If the implantation failure "lateral" contact out of the study expects to get a survival rate of 96.8% 10-12 years *
•
•
•
The HHS is remarkably good at Spiron patients.
Bone condition for a revision is excellent. Calculations for bone remodeling are consistent with X-ray processes.
Application of Spiron useful for patients who are still experiencing revisions. In the older age standard hips and
also cements supplies are meaningful.
* For reasons of simplicity, the prostheses were summarized by 10 to 12 years in a group
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Further studies
B. Ebbecke, Universiy Hanover
Institute for constructional mechanic and numerical mechanic
Numerical studies of Spiron – Prosthesis
Results of bone remodelling by Spiron-prosthesis:
Density distribution in biological balance, 2003
Ebbecke, B. Knochenwachstum - Endlich verständlich. Zusammenfassung, University Hanover,
Institut für Baumechanik und Numerische Mechanik, 2003.
Nackenhorst, U. Ein effizientes Finite Element Verfahren zur Simulation des
beanspruchungsstimulierten Knochenwachstums. Tagungsband des Workshops ”Die Methode
der Finiten Elemente in der Biomedizin, Biomechanik und angrenzenden Gebieten”, Ulm, 1997.
Nackenhorst, U. und Schröder, U. Numerische Simulation des beanspruchungsinduzierten
Knochenumbaus am Beispiel endoprothetisch versorgter Femura. Bericht aus dem Institut für
Mechanik, Hamburg, 1997.
Ziefle, M. Numerische Untersuchungen der Druckscheiben Prothese. Zusammenfassung,
Universität Hannover, Institut für Baumechanik und Numerische Mechanik, 2002
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Study for comparative primary stability 2005
•
•
•
•
•
In collaboration with the animal
medical school and the MHH
Hannover Medical School
(Department of Trauma
Surgery), a Investigation of the
femurs of shepherds carried out:
3 groups (same age, same size,
similar bone quality):
15 femurs without prosthesis
15 femurs with Spiron
15 femurs with cementless
standard stem type
"Zweymüller”
Article title: Less motion in bone/prosthesis interface by the new uncemented short-stem prosthesis
Spiron(R) in dog bone
MS ID
: 1648004516228708
Authors
: Ulrich Wiebking, Björn Birkenhauer, Franziska Hühn, Christian Krettek and Thomas Gösling
Journal
: Acta Veterinaria Scandinavica 2007
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The investigation
In laboratory
The test machine
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Results I
Spiron
Terminal of the investigation:
The fracture
CoST OP-Kurs Hüftgelenk
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Zweymüller
12.04.2013
Result
Strength – Time-Diagram
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Result
blue = Spiron; red = Zweymüller; white = without prosthesis
Vergleich Max. Prüflast, blau: Spiron-Prothese,rot: Zweymüllerprothese,gelb: ohne Prothese
6000
5000
Kraft in Newton
4000
3000
2000
1000
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Hundefemora
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Result:
Maximal stress at femur fracture
Mittelwert max. Prüflast
4500,00
4000,00
3500,00
Kraft F in Newton
3000,00
Natural
Femur
2500,00
2000,00
1500,00
1000,00
Femora
with
Spiron
500,00
Femora
with
Zweymüller
0,00
Femora mit Spiron-Prothese
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Femora mit Zweymüller-Prothese
B. Birkenhauer
Femora ohne Prothese
12.04.2013
Elasticity of the system „Prosthesis in bone“
(Force in Newton vs. distance in millimeter)
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The „Helica“-Prosthesis in the veterinary medicine
Due to the good biomechanical results
of that investigation was the Spiron prosthesis
under a new name directly Introduced in the veterinary
medicine
.
Hach, V., Delfs,G.: Initial experience with newly developed hip endoproethesis;
Vet Comp Orthop Traunatol 2009; 22: 153-158
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Result
A major factor of the
primary stability is the
preservation of the
elasticity of the bone.
But a stem prosthesis
increases elasticity and
stiffens the proximal
femur. A femoral neck
prosthesis can maintain
the elasticity of the
proximal femur.
CoST OP-Kurs Hüftgelenk
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Indications
• Good bone quality
• Physiological hip joint
geometry
• Biological age <65
• BMI?
• (No previous surgery)
• good compliance
• Beware of arthritis with
periarticular osteoporosis
• Approx. 15 - max. 20% of
hip replacement patients
CoST OP-Kurs Hüftgelenk
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Outstanding questions
1. Are Femoral neck prostheses short stem prostheses?
2. Are shortstem- und femoral neck prostheses
biomechanical equivalent?
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Thank you for your attention!