Monday, December 5, 2022

C-leg vs Rheo 2 vs Pli=?ISO-8859-1?Q?=E9_?= 2.0

Lars W. Andersen

Dear list,

Middle of November last year, I wrote about opinions and
benefits/weaknesses about MPC legs for ppl in my situation. Left
femur, right Crux amputees.

I have now had the pleasure of trying out all three mentioned MPC’s
and the comments and tips I received was very helpfull in that
process. So thank you everyone on the list who responded. I have
received a healthcare approval and have decided and aquired one of the

First of all – I think that we are still very early in the evolution
of MPC’s. Many features seem engineer driven and not necessarily
something I as a user has any benefit out of, and there is too much
“following your competitors” and too much evolution in there. A little
more true invention and breakthrough would be nice. But still – when
like me coming from an old pneumatic leg that only allows me walking a
a predetermined pace, going with any of the MPC’s gives me a clear
advantage. That was clear after walking the first few steps on any of
the three knees …

**** DISCLAIMER … The following is my impression as a user, based on
my limited testing, and does not necessarily reflect the opinions of
practitioners and other professionals I have met in this process. ****
(read – I’m not trying to step on anyones toes .. just trying to give
my immediate feedback)

1. The Plie 2.0
I only had the opportunity to try this out for one day, but despite
the setup being down to – “bolt it on and start walking” it was by far
the smoothest leg “out of the box” and the easiest to start walking
on. I haven’t been running since I tried to stop a train 24 years
ago, but after putting this leg on, I was taking my first running
steps, less than 30 minutes later … That kind of sold me on the idea
of MPC’s …. I also liked the idea of an interchangeable battery.
But I seriously doubt the water resistance and there was wires hanging
semi-loose on the inside. I works as a freelance IT consultant,
helping customers choose between a number of different products and
there was just something about this product that didn’t seem “solid”
to me. And when looking at the time frame for a healthcare approval I
had to think long term. If it was the third generation and not the
second, I might reconsider. Also – I don’t know how easy it would be
to service this leg if it failed while I am travelling somewhere
outside US or Europe.

2. The C-leg.
It took me about 2 weeks to learn how to use the c-leg, and from then
on I loved it! It was predictable, yet did what I needed to do, but I
had to learn how to use it. There wasn’t the same initial “this is
nice and fits me well” feeling as with the Plie 2.0. But
“predictable” is a good thing I guess. Giving the trial knee back
after 3 weeks and returning to my old knee was a sad experience.
There is a learning curve, and having a good practitioner that was
able to explain to me how to use it, and how to gain trust in it was
VERY helpful.

To sum it up. After set up to suit me, it just works the same
predictable way every time you take a step in the same way. I’d
definitely want that if I was a new amputee. Downside is that it locks
when running out of battery. First thing I did was to run the battery
dry to see how that worked. It didn’t. Try walking with a leg in a
cast, without crutches … it’s impossible!! Imagine going on long
flights where you might not be anywhere near an outlet for a while.
Not cool. And imagine sitting in an airline seat on couch, and having
a locked leg?? Not possible.

Another thing is the quirly “second mode”. My cardio consist of me
working out on a stationary bike, and having to jump on my toes all
the time in my gym … jeeez … That is something only a sick and
twisted engineer could come up with (I’ve studied engineering myself).
And the other option is a remote for doing that? I’m logging enough
stuff around already. So another remote … no thanks. Why not
something more subtle like pushing/tapping a button on the back of the
knee at a preset customized interval. Or something else? Spend a few
days coming up with something more clever should produce results …

Another downside is that you are locked into the Otto Boch components
… feet etc.

3. The Rheo 2
I only had the opportunity to hold and play with the Rheo 2 a few
minutes, and read about it for a few months. I liked the features in
theory but didin’t know how they would work out in practice. But
eventually I got a trial set up, and I had the possibility to walk on
it for 3 weeks. I ended up cancelling my return appointment to borrow
it for a short trip I to Madrid – and thanks for that!! I wouldn’t
have seen much of the city on my old knee Saved me on room service
bills too 🙂

Features i like: When I am not putting pressure on it, it swings
relatively free. Saves me from the c-leg “second mode”. And it works
fine. One thing I didn’t know untill the trial is that the more
pressure/weight on it, the more resistance in the knee. So you have to
trust it and put all weight on it to lock it. In practice this works
REALLY well. But i could imagine newly amputees having a problem
trusting their knee. The first 20 years, I required having my knee
lock completely once the heel was touching ground. But then … maybe
thats just me. But I quickly got to trusting the Rheo 2, and after
that it was VERY natural in the way that it switched between swinging
freely and giving resistance. Another added benefit is if you want to
get into your car quickly, you don’t have to wait for the knee to
bend. Just take weight off it, and you can hurl it into your car.
Nifty on narrow streets with lots of traffic.

The swinging freely is also the mode it enters when running out of
battery. With my stable setup, I can easily walk on it, and I really
need that feature.

From what I understand, Ossur is everywhere, so I wouldn’t be too
concerned about going on long trips with this knee.

It holds battery pretty well … I sit at a desk or in meetings a lot,
and it took me 36+ hours before I managed to drain the battery
completely. With higher activity – more walking I’d imagine it
draining quicker though. Should I be sitting on long flights, I can
turn it off completely. Nice touch for saving battery. And recharge is
quick – 2-4 hours.

There is a bit of “grinding” feeling once in a while due to the way
the knee works – The liquid and the discs controlling the liquid,
working. But it doesn’t in any way affect how I walk on it. Also – all
the hydraulic knees I have been walking on have lost the oil over
time. I like the idea of having something else than old-school
hydraulics. Off course that might lead to new and unexpected problems
… but lets see.

Downside is that it is a bit heavier, but in reality I can’t feel any
real difference in that respect.

To sum it up …. all three legs are for me, MUCH better than the
older manual knees. Mostly the ability to walk naturally and with less
energy at different speeds is a killer feature. Especially being able
to walk FASTER, where I earlier had to work harder, is a nice touch.
I also feel like walking more naturally and after receiving a little
training correcting some of the bad habits collected over 20 years,
gives me the ability to more fully appreciate these knees.

And all three knees were giving me this, so in reality I could be
happy with any of them. It was down to add-on features and my “gut
feeling” for choosing technology that was stable and durable enough.

I ended up going with the Rheo 2, because I liked the features that it
gave me, and overall solid look feel. If I was a new amputee though, I
probably would have gone with the C-leg, due to the better stumble
control and the more “predictable nature” of the c-leg.

The post got a little longer than intended, but I hope that my
observations can be helpful to some of you. If there is one thing I
need to stress, make sure that patients “stick with it” when trying
out a new knee. Make sure they walk AT LEAST 2 weeks on it, before
judging on it.It takes time to build up enough trust to let the knee
“do it’s thing”.

If you should have any followup questions that you think would be
helpfull, please email me, and I’ll get back to you. Or if you have
patients with questions, let me know if I can help. I won’t recommend
one knee over the other – it’s all about understanding one’s own needs
and choosing the right one for you. I can only help descrbe what
should be considered, and describe how I perceive the different
properties of each knee.

best regards
Lars W. Andersen | [factus]
Microsoft Infrastruktur, Integration & .NET
M: +45 20 46 80 20 | E: [email protected]


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