How does the human knee move?
There are two phases of motion – the first takes your knee from fully extended
to being bent approximately 90-degrees. The second phase of motion is when
your knee moves past 90-degrees
until it is fully bent, which
is about
155-degrees.
During this first phase of motion, the knee literally pivots,
with the outside compartment of the knee moving backwards more rapidly
than the inside compartment. Past 90-degrees, your knee moves backwards
evenly,
with a combination of rolling and sliding.
Traditional knee
replacement designs
How do knee replacements move? Unlike your natural knee,
most knee replacements lack any pivot motion. The movement consists of
sliding and rolling through both phases of motion, with only a slight
pivot of the outside compartment (rather than the inside compartment
like your natural knee).
Also, your knee cap can become slightly misaligned when
your knee is fully bent. This makes your quadricep muscle pull at an
awkward angle, which causes pain and discomfort.
The
JOURNEY* knee
How does the JOURNEY knee move?
Just like your natural knee, the JOURNEY knee has two distinct phases of motion—the
first takes your knee from
being fully extended to being bent approximately
90-degrees. The second phase
of motion
is when your knee moves past 90-degrees until it is fully bent, which
is about 155-degrees.
During this first phase of motion,
the knee pivots in a similar fashion
to your original knee, with the outside compartment of the knee moving backwards
more rapidly than the inside compartment. Past 90-degrees, your knee moves
backwards nearly evenly, with a combination of rolling and sliding as your
natural knee would.
For more information about
knee replacement surgery, visit www.MyLifeInAction.com.
*Trademark of Smith & Nephew.
For more information, please contact Lewiston Orthopaedic Associates
