What`s New in Knee Replacement

What’s New in Knee
Kenneth D. Kleist, M.D.
HealthPartners Medical Group
Regions Hospital
St. Paul, MN
Goals of Knee Replacement
• Improve the quality of life
by improving pain and
function while maintaining
range of motion and
avoiding complications.
• 85% of Knee replacement
patients say they would
have the surgery again.
What is a joint replacement?
What is a partial knee
Minimally Invasive Surgery
• No good consensus on what this means
– Less skin incision
– Less tendon/muscle splitting and damage
– ??? More rapid recovery
• Certainly there are benefits
– Cosmetic, psychological, blood loss, recovery
• Bottom Line
– Need to have pieces put in right!
– Long-term survival of the joint is most
• Medial Parapatellar
• Mini-Medial
• Mid Vastus
• Sub Vastus
• Quad Sparing
Pain Control and Rehabilitation
• Regional Anesthesia increasing
– Spinal or Epidural Anesthesia
– Femoral Nerve Blocks
– Pre-op Medicines
– Pain Catheters, continuous or on
– Local anesthetic intra-operatively
– Cryocuff for icing
– Long-Acting Narcotics
– Less Intravenous narcotics
– Pain as a vital sign
Better Nausea Control
• Much more focus
– Regional Anesthesia Helps
– Multimodal approach
• Less intravenous narcotics
• Scopolamine patches
• Odansetron
• Prochlorperazine
• Metoclopramide
Post-operative Physical Therapy
• Early mobility is helpful
– Continuous Passive Motion
(CPM) the night of surgery
• Start at high flexion right
• Set goals for range of
– Up on your feet the first
post-operative day
– Discharge on the third postoperative day
– Transition from walker to
cane to nothing
How much flex is enough?
• High flexion implants
– Theoretically allow higher range of motion
• Traditional Implants 125, maybe 135 degrees
• Some now up to 155 Degrees
– Caution: High flexion does not mean you definitely will
get better motion.
– Setting Expectations is Important
• Best predictor is pre-op motion
• Knee will not be normal.
– Can make the surgery slightly easier by removing
extra bone
– Can provide additional implant options.
Gender Specific
• 3 anatomical shape differences
– Females are narrower
– They have a different angle the
knee cap glides through
– They have thinner area at the
front of the bone
• Most companies now address this
in some way
– Shape change
– Sizing
Mobile Bearing TKA
• Rotating Platform
– Plastic liner rotates in the metal
– May decrease wear
– May improve motion
– May allow fudge factor
– However may also increase wear.
– More difficult to insert plastic
Highly Crosslinked Polyethylene
• Relatively New
– Not as accepted as in the hip
• Goal is to reduce wear
– Still long-term questions
about mechanica strength to
fracture resistance and
– Not common used by most
surgeons yet except in
limited cases
• Very young patient
Other Alternative Bearings
• New approaches to
femoral components
– Ceramics
– Oxidized Zirconium
Computer Navigation
Still Controversial
May improve overall alignment
May improve the accuracy of sizing
Possible it may improve long term outcome
Increases time
“Garbage In, Garbage out”
May place you at a minimal risk for fracture
Awaiting long-term data
Direct to Consumer Marketing
Current State of Patient’s Decision
Making in Today’s Market!
• The best advice is to
have a discussion with
your surgeon.
• Balancing Act
– Patients needs/desires
– Surgeon training,
experience, and skill