Knee replacement in young patients deals with issued involved in choosing the procedure when inevitable. MJRC offers knee replacements for young patients in Chennai, India. Visit www.kneeindia.com

1. Dr.A.K.Venkatachalam
MS Orth, DNB Orth, FRCS, M.Ch Orth
Consultant Orthopedic surgeon
Chennai
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2. * < 65 years , Better is < 50 years of age.
* Life expectancy of > 20 years
* Family history of longevity
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3. *Numbers increasing in
young patients < 55
years
Australian registry
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4. “If the historical growth trajectory of
joint replacement surgeries
continues, demand for primary THA
and TKA among patients less than
65 years old was projected to exceed
50% of THA and TKA patients of all
ages by 2011 and 2016, respectively.”
* Steven M. Kurtz PhD, Edmund Lau MS, Kevin Ong PhD, Ke Zhao
MA, MS, Michael Kelly MD, Kevin J. Bozic MD, MBA
Symposium: ABJS Carl T. Brighton Workshop on Health Policy Issues
in Orthopaedic Surgery
Volume 467, Issue 10 / October , 2009
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5. Secondary osteoarthritis from
* Post traumatic arthritis
* Rheumatoid arthritis is the main cause
* Whereas in older patients, Primary OA is the
leading cause.
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6. * Against-
1)Total knees fail more often in young patients
FAILURE RATES AND AGE
AGE( years) FAILURE RATES
< 65 years 12%
65- 75 years 10%
> 75 years 4%
Robertsson, Thesis Lund 2000 , Swedish arthroplasty register
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7. *than their older Age & activity after THR/TKR
colleagues
*Wear is proportional to
usage. Patient age Average of
*Young patients walk on steps/year
average upto 50% more < 60 years 1200,00
than older patients.
*Usage leads to increased
poly wear > 60 years 800,00
*Poly wear leads to aseptic
loosening
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8. *Young people live LIFE EXPECTANCY( WOMEN)
longer.
*Young people survive AGE(years) Expected to
their prosthesis. live further
*Older people die
before prosthetic 50 years 32 years
failure.
67 years 18 years
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9. * Previous three slides indicates that there is a
higher risk of failure in young patients and they
may require a revision within 10 years
* Surgeon knows this. He also knows that the
revision will be technically a difficult operation
than the primary. Result also will be inferior.
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10. He is unwilling to listen and wait.
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11. * severe pain and stiffness in the knee joint,
* Impaired quality of life,
* Failure of previous treatments of the painful
hip / knee joint.
* Specially suitable candidate is a young patient
with severe impairment of both hip and knee
joints eg- Poly arthritis like rheumatoid
arthritis / sero-negative arthritis.
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12. * The OS can do a TKR with a prosthesis that
wears out slowly.
* Use of materials, techniques, activity
modification can lead to better implant
survivorship.
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13. *Prolong prosthetic life, preserve bone
while providing function.
*Search for design, durability of counter-
face, poly, technique, best fixation.
*Education of patient about permissible
activities of daily living and sport.
*Explain possibility of a future revision.
*Prevent late metastatic infection from a
remote source.
*Encourage treatment if the patient has
fully understood all issues.
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14. * Baby Boomers
* Relatively healthy
* Wanting the best technology
* Are relatively dissatisfied with current outcomes
* Will out live current total knee technology
* The main contributor to knee replacement
growth
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15. Patient expectations start rising
concomitantly.
Internet savvy
Want only broken part to be fixed
As small scar as possible
No pain
Want to dance, participate in sports
Want alignment perfect, stability
* Surgical outcomes ≥ Expectations
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17. * Cycling
* Calisthenics
* Swimming
* Low-resistance rowing
* Skiing machines
* Walking & Hiking
* Low-resistance weightlifting
Knee society
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18. *Baseball
*Basketball
*Football
*Hockey
*Soccer
*High-impact aerobics
*Gymnastics
*Jogging
*Power lifting
Knee society
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19. Wear is an issue. Steps to reduce wear
*Bearings- alternate bearings like oxidized
zirconium, ceramic
*Poly ethylene X3 poly, anti oxidants,
thickness.
*Cemented vs cementless fixation
*Accuracy of component placement- ?
Navigated surgery
*Fixed vs mobile bearing components
*Single radius vs multi radii designs.
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20. Wear in TKR’s
Patient
Counter face
Polyethylene
Technique
Design
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21. *Change femoral
counterface ( Oxidized
zirconium, Ceramic)
*Change Poly insert
( XLPE)
*Change design
* Mobile vs fixed bearing
* CR vs PS
* Single vs multiple radius curve
* Locking mechanism
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22. * X linked polyethylene seem to be advantageous
at least from the hip side.
* Proved lowering of long term wear rates
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23. THR TKR
Contact stresses low High
Wear abrasive/ adhesive fatigue
Crack propagation Less important
Important
Highly cross linked polyethylene is
advantageous in the knee also.
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24. *Behaves differently in 60
clean and abraded
environments We 50
*Wear increases in abraded ar 40
CoCr/CP
environment with cobalt rat
e 30 E
chrome for both polys m CoCr/XP
*Hence highly cross linked m3 20 E
poly may not be the best /M
C 10
material in the altered
environment 0
-10
Clean Abraded
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25. * Sequentially irradiated and annealed ( not
melted polyethylene)
* Significant wear reduction
* No mechanical changes
* Same poly used for hips and knees
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26. * Scratches are bad - Ideally try to eliminate
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27. * Conventional cobalt chrome is used for femoral
and titanium or highly polished cobalt chrome
used for tibial base plate. Polishing of tibial
tray reduces back side wear.
* Pure Ceramics
* Oxidized zirconium
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28. *Femoral
*Cobalt Chrome
* scratching is common
*From cement and poly
*Care to remove cement
after TKR.
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29. * Meet requirments for ideal TKR
* Smoother
* ↓ Coefficient of friction
* More scratch resistant
* Less wear against both conventional and highly
cross linked poly ethylene.
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30. * Polyethylene wear performance of oxidized
zirconium and cobalt chromium knee components
under abrasive conditions
* ( Ries MD, Salehi A, Widding.K, Hunter G.,JBJS ( Am)
2002)
Oxidized Zirconium femoral components reduce
polyethylene wear in a knee wear simulator.
( Ezzel
KA, Hermida JC,Colwell CW Jr,D’Lima DD,
CORR, Nov 2004)
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31. * Zirconium- metallic element
* Zirconia- ceramic
* Zr-2.5 Nb Metallic alloy
* Super heating zirconium to
500+°C in Oxygen presence
* Surface transformation into Air
500oC
zirconia ( ceramic oxide) Oxygen
Diffusion
* Chemically bonded ceramic
oxide surface 5μ thick Original Surface
Ceramic Oxide
Oxygen Enriched Metal
Metal Substrate
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32. * It is a metal component
* Thin layer of ceramic like material that is part of its
innate structure. This is not a coating.
* Ceramic oxide is 5 μ thick
* Biocompatibility is excellent, matches titanium
* Very low coefficient of friction vs Cobalt chrome.
* Extremely abrasion resistant.
* Hard like ceramic
* Equivalent strength properties to Cobalt chrome.
* Adverse to chipping that can occur at insertion and
over time.
* Lack of Nickel allergy.
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33. *Equivalent to Cobalt
Chrome
*1000 pounds
*10 x 106 Cycles
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34. *Oxdized zirconium
produces fewer PE
particles when
compared to Cobalt
chromium
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35. *Oxidized zirconium
reduces volumetric
wear by upto 89% in
an abraded
environment when
compared to Cobalt
Chrome
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38. * Strength of Cobalt chrome
* Low coefficient and scratch resistance of ceramic
* Non brittle as the ceramic layer is part of the innate
structure.
* Decrease wear is the main advantage.4900 less
volumetric wear.
* 160 times smoother.
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39. *Many variables
*Articular congruity
*CR vs PS
*Fixed vs mobile bearing
*Single radius vs multi radii
*Locking mechanism
*All have in- vitro/theoretical evidence
of benefits.
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40. * Cemented TKR is the gold standard at present
* However Cement constitutes a third body
wear.
* Best fixation is biologic with bone ingrowth
into prosthesis.
* Examples of hips – Uncemented hips are
standard in young patients.
* Cementation leads to extra operative time
* Part results of poor cemenless fixation stem
from metal backed patellas.
* Cementless fixation will be the preferred
method in future.
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41. *16 knees from 2007 to 2009 in patients ≤55
years
*Cobalt chromium femoral components in 8
and Oxidized zirconium in 8 knees.
*CR- 6 knees, PS- 10
*Diagnoses-
Post traumatic arthritis-2
Rheumatoid arthritis- 6
Osteoarthritis- 8
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42. * Knee scores improved in all.
* Range of movement from 95 degrees to 140
degrees.
* No loosening
* 1 patient with bilateral TKR has anterior knee
pain, had patellar component revision
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43. *Skin incisions 4- 6
inches long.
*Midvastus, sub vastus,
minimally invasive
quad splitting.
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44. *46 year old Indian
housewife.
*Left gender specific
high flex knee
replacement
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46. *Zero error Component placement
*Extra articular deformities- one stage
replacement
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47. *Patient specific
instrumentation
*Requires MRI scan &
Standing x rays
*Eliminates 23 steps
from TKR.
*For distal femoral cut
& proximal tibial cut.
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48. Rheumatoid arthritis 38 year old
patient
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52. * Durable materials like Oxidized zirconium,
cross linked poly, highly polished tibial base
plate
* Single radius femoral prosthesis
* Computer assisted knee replacement
* Patient specific instrumentation( custom fit
surgery)
* Minimally invasive approaches
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53. QR code
E mail- drvenkat@kneeindia.com
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