This article is a rispomparison of a selection of mechanical and MPK microprocessor prosthetic knee joints for above knee prosthetic legs. I have been testing prosthetic knees such as Orthomobility‘s innovative VGK „Very Good Knee“, which I compare to Otto Bock‘s 3R80 mechanical knee and Ottobock‘s microprocesser C-Leg knee, as well as Otto Bock‘s electronic Genium knee.

All of these are first-class prosthetic knee joints for active above-the-knee amputees, have both swing and stance control. In other words, all of these prosthetic knees enable different walking speeds, going down hills by putting weight on the knee while it is bending, going down stairs step-over-step. Also, each of these knees supports a natural walking style with the knee bending slightly and bouncing back after heel strike.

And yet there are differences, which, according to my opinion, become apparent when it comes to activities beyond walking and taking stairs:

  • Kneeling on the floor (should not make scratches, neither on the floor nor to the prosthesis!)
  • sitting down (knee should ideally swing freely)
  • going down really long hills or very many stairs (knee hydraulics becoming warm!)
  • having contact with water (most electronic prosthetic knees don‘t like that!)
  • bearing additional weight (knee function might be adjusted for a fixed body weight only)
  • wearing different shoes (having different weight, which has an impact on the swing phase!)
  • sitting in a narrow place (the more knee angle, the better!)
  • feeling the weight (a heavy prosthesis can be a real problem with a short stump!)
  • Design. For amputees who do not want a cosmetic covering, design matters!

So this is how I compare Orthomobility‘s „Very Good Knee“ VGK with Otto Bock‘s mechanical 3R80 and electronic C-Leg 3 and Genium resp. Genium X3. I don’t include polycentric constructions such as Össur’s TOTAL KNEE or Endolite KX06 (with a Mauch hydraulic unit) because with my activity level I regard the geometric locking mechanism more a hindrance than a feature.

I use colours to say whether an aspect is

very good
quite good
could be a problem
bad disadvantage
VGK 3R80 C-Leg Genium
Manufacturer Orthomobility Otto Bock Otto Bock Otto Bock
Type Mechanical, with innovative autoadaptive fluidics control Mechanical Electronic Electronic, with more sensors than C-Leg, being able to adjust to more different situations
Swing phase control
VGK 3R80 C-Leg Genium
Different walking speeds yes, slow to very fast yes, but not such a wide speed range. I haven’t found a setting supporting both very slow and very fast. yes, slow to fast yes, slow to very fast.
Effect of different shoe weight none. fluidic control adjusts automatically to different shoe weight bad. Heavier shoe means slower swing phase. Would require adjusting a screw setting to compensate bad. Havier shoe means slower swing phase. Would require different programming to adjust. none. Electronics compensates by adjusting the hydraulic unit automatically.
Natural walking style with knee bending and bouncing after heel strike yes, requires a bit of practice and a proper adjustment of the foot yes, requires a bit of practice and a proper adjustment of the foot yes, initial knee bending motion (before bouncing back) is damped smoothly yes, automatically having a few degrees of knee flexion on heel strike (Otto Bock calls it „pre-flex“ function)
Stance phase control
VGK 3R80 C-Leg Genium
Effect of additional weight, e.g. when bearing something none. Fludic control is able to compensate bad. Stance control is weight activated. Bearing additional weight could lead to stumbling none. Electronics compensates. none. Electronics compensates.
Effect of long descends or or long stairs down none. Fluidic control compensates. bad. The warmer the hydraulic unit gets, the more it looses its stance control function. OK. Electronics compensates by adjusting the hydraulic valves. However, due to the nature of the hydraulics, it might become too warm and then switch into a „safe mode“ with no knee bending function. OK, same as with C-Leg
Swing characteristics when not walking Stance control active. knee is relatively stiff. This is the price for having a “safe” knee, which does not bend unintentionally. OK. Swings almost freely, slightly damped by spring Bad. Stance control active, knee is relatively stiff Best. Knee swings freely.
Cycling Mode yes, to be activated with a small handle. With configurable knee resistance and security mode: In cycling mode, a quick movement of the knee will give sufficient stability to stand on a flexed knee. yes. Normal mode is fine for cycling. yes, to be activated with a special 3-times tipping on forefoot. Second mode characteristics can be configured. yes, to be activated with a remote control, or as with C-Leg. Multiple „second modes“ with configurable characteristics.
Aspects for every day usage
VGK 3R80 C-Leg Genium
Maximum knee-angle perfect! Only restricted by the socket! With my short stump and socket, there is sufficient space so the knee can be bound to almost 175 degrees, which is the physiological kneeling angle of a sound leg. good! knee can be bound to 160 degrees bad. Only about 120 degrees, prothesis could feel like an obstacle, depending on the situation OK, much better than C-leg.
Kneeling down Well supported by a plastic knee cap that protects the floor and prevents slipping away Moderate. Weight is supported by plastic cover. However, the ottobock 3R80 logo gets scratches. With previous 3R80 model, foot goes up. OK, but only if knee protector is mounted. Very bad. Would slip away on hard floor and/or make scratches in knee frame or floor.
Weight heavy, 1400 g OK, 1200 g heavy, 1400 g Very heavy, 1600 g. Could be too much for a short stump
Water-proof yes! Can be used under shower, and even when doing water-sports. However, should not be used in salt water. Don’t know. Probably a few rain drops don’t matter.Update: The new version (2014) is waterproof! No! Must be kept away from any water! Moreover, Charge socket is located such that even a few rain drops could cause damage. Update 2014: The Genium X3 is waterproof (however: even heavier and more expensive than the standard Genium)
Handling nothing special nothing special Requires almost daily battery recharge, battery connector is a bit difficult to attach. Requires battery recharge every few days, however, battery connector is easy to attach
Restriction on the choice of prosthetic foot No restrictions. Can probably be used with any prosthetic foot of your choice No restrictions. Bad. Only allowed with a few Otto Bock feet, none of which are my personal preference Bad. Same as with C-Leg.
VGK 3R80 C-Leg Genium

 

I invite you to leave a reply. I understand that every amputee has his or her own needs that may be different from mine, so it will be interesting to learn from you. Let’s make ampulife.com an ever better resource for above-knee amputees!

 

21 thoughts on “Compare Prosthetic Knees

  1. Hi,
    swapping from a Endolite KX06 to Very Good Knee (VGK) in few days poss couple weeks. The Endolite is/has been a good all round knee for high activity (well I think so) but when you kneel it extends from the chassis and on my latest one the dials rotate leading to problems. I’ve only had the problems this year so maybe the previous models were stiffer. I hear they may have a new model in the pipe but I can’t do with having to strip it down every few days.
    Wanted to say thanks for the site and info, for me weight of the unit is important. I’m getting mine on the NHS, I am also down for C-leg trial but if this one works I’ll stick with it. Kev

  2. I have read and re-read your great info several times since becoming an Above Knee amputee 3 yrs ago…being a younger(early 40’s ) guy I really wanted to pick a good knee…I found your view on knees similiar to how I think..I prefere simple,reliable and as light as reasonable..I got a polycentric at first but I also felt limited in activity for daily use( i.e., having to walk downhill was tough)..since I am ex-military with other injuries I am provided with options for electronic knees, but even after testing the C-leg and the Genium X3 I still decided to go with the 3R80 and 2yrs later zero regrets..I really researched the VGK based on your info and it would have been my second choice…I love the stance control, without the issues of electric knees..with electrics I was afraid to forget to charge it and worried if I went camping for several days without a charge..plus any adjustment reqquires going to the office to hook it to a computer, I did demo and have the option of the Genium X3 but no electronics can be really 100% waterproof…just wanted to let you know I found your website and research very helpful…it is nice to see someone with my view about non-electrics…it seems everyone else prefers them, but there are some definate disadvantages to them that can get overlooked…

    • Hi Shaun,
      thanks for your comments. It looks like your criteria for choosing a prosthetic knee are much like mine. Many amputees do not really inform themselves, and often the most expensive product appears to be the best, which is certainly not the case. Pricing in this industry is quite arbitrary. The VGK is far cheaper than most alternatives, because the manufacturers want to make this technology available to as many of us amputees as possible. It is certainly much easier to make $$$ by putting the price up, and thus perception of how „valuable“ or „good“ something is. The VGK-Short Transfemoral (for short stump, such as mine) would not have been developed without such an altruistic attitude.
      Karl

  3. Hi. I am an AKA in Singapore and am just now practicing with my new leg which is an Ottobock 3R78 and a basic type foot i think. I am 60years old next month but still very active. My prosthetist is going to change out my knee for the 3R80 which is way better than the 78. All up here in Singapore a leg with the 3R80 costs 9K Singapore dollars.

    A C-Leg here in Singapore costs about S$75K which is a fortune but it would be a godsend for me for what my activities are. There is no way i can afford it though especially after all my savings have gone into medical expenses. (Approx 150K+)

    Can i ask all you guys how you all can afford such a prosthesis? Or are you all getting it subsidised or something. Beats me how the manufacturers can charge prices like they do and expect the general public to be able to pay for them. I read somewhere recently that there are in excess of 60,000 amputees with the C-Leg.

    Anyway, thanks to you all for contributing to this site with the info and feedback you all have. It is very helpful to new ampu’s like me. Cheers.

    • Hi Carl,
      I very much agree with your comments on pricing of prosthetic legs. I live in Germany, and the public health system provides for prosthetic legs. No problem to get a C-Leg if you prove that you can make use of the benefits. However, what really matters is socket fit, as you might know from your own experience. There is a lot of „hype“ about microprocessor knees. I had been using a C-Leg for many years, but later experienced that I could do much better with a 3R80, simply because of the weight! My current prosthetic knee is the „Very Good Knee“ (VGK), as you can see on my website. This is non-microprocessor, but having a lot of advantages (such as waterproof, no need for charging), and yet, it is a CONTROLLED hydraulic unit, being able to adjust hydraulic resistance according to the situation (weight, temperature, etc.). However, is not ELECTRONICALLY controlled, but with some other kind of technology called fluidics. The C-Leg, on the other side, is using electric motors to permanently adjust hydraulic valves. That’s why the C-Leg needs regular servicing (I think they replace these motors, as well as the batteries). So there are alternatives, however, what matters most is socket fit.

      • Hi Karl,

        Thanks for your reply. I was lucky enough to get changed out to a 3R80 knee last Friday which my prosthetist was kind enough to arrange for me. I am really impressed with the better control over most functions with this knee compared to the 3R78 which really is better suited to a person who will not do much except for a little flat walking each day.
        The 2017 model of the *80 is waterproof which is a plus for the hot days here in Singapore.
        Although i would very much like to get a C-Leg in the future i am going to enjoy having this new knee to use right now.
        Look forward to hearing more from your readers on this site for any new updates and info that will help us ampu’s in the future. Cheers Carl

        • Hi Carl, just a comment on these knees: I had switched to a 3R80 (old model) after having used a C-Leg for a number of years. Primary reason was weight, and the fact that the C-Leg requires a relatively heavy foot in order to swing properly. There are other advantages of the 3R80, such as the better maximum knee angle. Also, you mention waterproofness! Of course the C-Leg is much superior in other aspects, such as security and better adaption to various walking speeds, however, I would not say that any particular knee joint is better than an other, just because it may appear so from the pricing aspect!

  4. Hi, my name is Ben. I’m a right through-knee amputee (knee disarticulation).

    I have tested the Kenevo, C-Leg 4 and Genium. I really love my Kenevo, it is nice, stable and lightweight but it lacks speed (2mph max). Battery life is 24hrs with magnetcharger. It doesn’t do much but it does it excellent.

    The C-Leg is much faster and has a cycle function. This is quite tricky to engage but works fine. It is a lot heavier than the Kenevo. This is still a safe and stable knee to use. A major improvement over the Kenevo. Battery life is about 2 days with stupid plug-in charger.

    The Genium is a bit heavier than the C-Leg and gains a remote control and the function to mount stairs in a normal way. It also has a jog mode but I have not testen it due to problems with my other leg. Batterylife is 4 days with ease and it works with a magnetcharger like the Kenevo.

    The biggest difference between the C-Leg and Genium: Genium is much more fluent and feels more natural. The C-Leg trends to feel a little square in its movements.

  5. Hi I have been reading your site as look at purchasing (out of pocket) a 3R80. I play golf with an old Mauch that they no longer support. I cannot find out if the 3R80 will actually lock in a flexed position – what I need for golf stance and swing.

    • I can only tell from my own experience with Ottobock 3R80 and I do not think it does lock. However, it should be in stance mode, which is a relatively high resistance to bending. Maybe you can stabilize the prosthetic knee by pushing the stump backwards from the hip.

  6. I was given a C-Leg (1st Gen) as my first knee (with an Ossur foot, shush…), and I hated it for it’s weight. It felt like it was always pulling off me. And the fact that I couldn’t get it wet put me in a horrible position when not at work as a toolmaker. In my offtime, I was a biker and fisherman in SE Louisiana, neither of which I could use the leg for. I eventually found a secondhand Mauch-style hydraulic knee that I exchanged for the times I needed weather protection, and I loved it. It was so much lighter, and I found myself wearing it full time. It doesn’t have the safety of the C-Leg, and I’ve fallen for the first time wearing a prosthesis, but the freedom gained was worth it. Now I switch between the two as the activity dictates.
    I would love to find a lighter weight knee that I could ride motorcycles without fear of getting caught in the rain, wear on a boat fishing without fear of getting splashed, and still has a normal walking style and safety. I want it all.

  7. Hello, I very much like your website and find it very informative. I am also a short stump AKA. I must point out however that many of the red, or negatives listed C-leg have been mitigated with the introduction of the C-4 C-leg. I obtained mine right when it was released to the general public and there are stark differences between the new C-leg and its predecessor.

    Thanks for your work help others.
    Kirk Billingsley

    • Hi,
      The comparison so far indeed covers the C-Leg 3 only. The C-Leg 4, according to my information, is very much like Ottobock’s Genium knee. However, I have no first hand experience with the C-Leg4 yet. Therefore, please share how you classify the C-Leg 4. Also, I welcome everyone to share their experience with other prosthetic knees, such as Plié and other high end knees. Let’s together make this page more informative for us amputees by adding your first hand experience.

      • My C-Leg is the original from 2004. Tried out C-Leg 4, did not find it much different. Using the Genium prosthetic knee.
        Much improved over the C-Leg in any aspect. I am a hipdisarticulated amputee since 1972.

  8. hi there my name is Carl and have taken part in some similar trials in Leeds England.
    it is interesting to see the results and compare them with my own. some of the results i agree with but you did not rate the 3r80 which is the knee i use and find it actually better than the C leg. mine is waterproof which means i can go swimming with mine and i can usually walk for quite a distance. i agree i have to careful which shoes i buy and which shoes for where but what i don’t agree with from my trials is that i found the Geniunm to be brilliant i could walk down slopes more confidently walk using less energy, unfortunately in England they don’t prescribe microprocessor knees on the NHS

    • Just a general update – as of 2017 they are now prescribing Micro Processor Knees on the NHS to certain patients. There is an extensive assessment (cognitive, physical, psychological) followed by a 2 week completion of a trip/stumble/fall diary. Following that there is a 4 week trial on the MPK followed by another assessment to see whether there is an improvement which would justify the prescription. I had a chat with my prosthetist and she confirmed that NHS England will be auditing centres to make sure they are prescribing appropriately.
      The choice of knees is between the Rheo 3, C-leg (with Ottobock foot), Orion 3 and Plie 3. There are a lot of considerations including build height, whether you are happy with an Ottobock foot (which I wasn’t because I wear an Accent with adjustable heel), whether you have an iPhone or Android (yes, seriously – the Rheo 3 app is iPhone only, the C-leg app (Cockpit) is Android only).
      I selected the Rheo 3 to trial – iPhone user so I can switch the unit off from my phone for cycling and use the app for monitoring battery life. It seems like it will do what I want it to. I previously used an earlier Plie when I lived in the US and, while it worked well, it seemed to need a lot of maintenance. The batteries have since improved in the C-leg/Rheo/Orion so they don’t need charging every day (an issue for me because we camp) but I should be able to blag some charge from an admin office etc and the charging times have decreased dramatically in the 8 years since I got my Plie.
      I think if you do wilderness camping you might still be better off with the Very Good Knee (or the VGK-S for short stumps) because it doesn’t need charging at all.

      • Hi Tessa,
        thanks for the info. Good to know that the NHS in the United Kingdom is giving amputees more choices in respect to prosthetic knees.

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