Looking through my analytics from this side, I noticed that a review I did of OttoBock's 3R80 some time back still attracts loads of interest from the audience. So I though I re-publish this article, make it easier to find, and thus bring it back to people's attention.

Throwback to the summer of 2019: After almost six years it was time to say goodbye to my old prosthetic knee and start thinking about a new one. Since 2013 I had been using the Genium from Otto Bock in combination with the Triton foot. And all in all, this is a great knee which allowed me to be active and live a fulfilling life. Yes, I had some issues with this knee, as some of you know. But most of the frustrations over the last couple of years came down to the socket and not to the knee itself. There was only one thing that really bothered me: Not being able to use the leg in the water. 

As you all know, I love being outdoors. Walking in the hills, paddling along the coast, or spending time at a local crag - for me these moments are precious and something I cannot get enough of. Unfortunately the fact that the Genium is not waterproof put some - unnecessary - limitations on me and what I was able to do. 

So with the lifespan of my old prosthesis slowly coming to an end I had the rare opportunity for a new - maybe waterproof - leg. An opportunity not to be missed. An opportunity to think about my needs as an active user, to get advice from a trusted prosthetist - and here my collaboration with PACE was essential -, to chat with other amputees and potentially try out different models to see what works best for me.

When narrowing down my options I have, I came top with the following criteria:

• I am looking for a reliable knee that allows me to be active and out and about in mother nature.
• I need something that works even if I don’t have access to electricity for a couple of days. 
• I would like to have something that is not very demanding when it comes to care and maintenance.
• Ideal would be somethings that is waterproof as I know from the past that I don’t carry around a second leg where traveling. Something that makes sure I am not suddenly stuck when crossing a river during a hike, when traveling during the monsoon or heading to the pool without prior warning.

Basically: I want a simple to use prosthesis, a workhorse that allows me to be out and active in mother nature, no matter in which conditions.

• The longer you can test a leg the better. The more you are able to play around with different conditions and take the leg to the test for a variety of activities the better you can judge if a certain leg is the right one for you. Having said that, I must admit that I didn’t make the most of the opportunity I had. With a high workload during my trial period the time to take the leg through the paces was limited.
• In addition there were other factors that had an influence on the test. Some of them were expected, others came as a surprise.
• The weather was pretty shoddy during the majority of days during the trials. 
• I have been struggling with an ill-fitting socket for some time.
• Since my amputation in late 2005 I have been using micro-processor knees. First the C-Leg and the the Genium. 
• So the combination of switching from a micro-processor knee to a mechanical one, doing this with a socket that is often lose and prevents me from precise foot placement and trying this when the ground is slippery and wet come with its own challenges - and had implications on the trial period.

• Right from the moment I started using the 3R80 from Otto Bock I had a good impression of the prosthetic knee. It looks well made and my first impression was that it is just what I have been looking for: A solid workhorse. And it is waterproof for both fresh and salt water.
• Once the leg is aligned properly and the settings are correct, it allows for smooth walking with an almost natural gait. The 3R80 kept up nicely with varying walking speeds and changing lengths of my steps.
• The range of motion for the knee is great, making it easy to get in and out of a car, work around the house or play around with the kids.
• It is easy to adjustment the setting of the leg yourself. That is great when you feel more and more confident with the prosthesis and want to change the stance phase damping or the swing phase control. Flexion and extension resistance can be adjusted easily and independently of each other.
• Last but not least, the knee as a very simple but effective manual lock. It’s easy to use even with wet and cold fingers and allows you to navigate a slippery river crossings or carry a kayak safely from the car into the river.

• While my general impression of the leg was a very positive one, there were a few points I didn’t like. And please ne aware that some of them are not down to the knee itself, but are a consequence of my current set-up and day to day reality as an amputee. But as many of you might face similar issues, I thought I include all my observations into this review.
• It is important to note that it takes some time to get used to the 3R80. Especially if - as in my case - you have been using a microprocessor knee for close to 15 years. As this mechanical knee is a great knee and allows for smooth walking with a natural gait, it’s easy to forget that you are not using a micro-processor one. But as it behaves differently when walking downhill, downstairs or over tricky terrain, you need to make sure to actively engage with each situation and not rely on what you are conditioned to.
• I must admit that the trial period was too short for me to learn to use the knee confidently in a variety of changing environments, with different shoes, carrying heavier loads on my back etc. I felt the potential of the knee to handle a great variety of situations well. But to use the 3R80 confidently off the beaten track, with heavy boots and a big backpack, when tired and maybe not fully concentrating will take time and a lot of practice. Here I am pretty spoilt. With the C-Leg and the Genium changing shoes, walking in different terrains and handling a variety off loads wasn’t much of an issue. The knee adjusted automatically. It was even pretty forgiving in terms of bad foot placement and the like.
• As many of you know I am battling fluctuations in my residual limb - and as a consequence I haven’t had a well-fitting socket in years. A loose socket often leads to imprecise control over the leg and a bad placement of the foot. It also stands in the way of internalizing movement patterns and building muscle memory as every step feels a bit different. Combined with the challenge of getting used to a mechanical knee I had a few situations where I took a fall, both out in the hills as well as at home on our stairs.
• On one day I had the impression that the resistance of the knee suddenly decreased when walking downhill for a longer period of time/when the knee got hot. I did not have the time to follow up on this impression and run a systematic test. But just fearing that this might be the case had implications on my confidence, constantly expecting the knee to malfunction. One incident in which the leg fails and you walk with less ease for some time.
• Last but not least (and as the focus of the review is on the knee this might seem a bit out of place): The foot shell for the Triton had no holes. Given the fact that the 3R80 can be used in the water, there is quite a lot of potential for a mess after using it in the water. You use the rotation adapter, get the foot a bit higher in order to get into a shoe and … you are all wet. Otto Bock has addressed this issues recently and I heard that the new foot shells have drainage holes. 

So, what do I think of the 3R80 from Otto Bock? If you are looking for a sturdy workhorse that performs well in a wide variety of conditions and off the beaten track, this knee is worth looking into. The fact that it is waterproof is another added bonus which I really enjoyed. It makes life for an active amputee so much easier. So does the fact that it is a mechanical knee. No need for charging. Again something I really like. 

If you are willing to put in the work and do not mind taking a fall or two when working on the ideal settings for all your adventures, this might be the knee for you. Given the comparatively low price tag (as compared  to the waterproof Genium X3 and others), the 3R80 is a great option.

Having said all that, I don’t think I will settle on the 3R80 as my next prosthetic knee. While I really like the idea of a mechanical leg that allows me to be off-grid for as long as I chose to, I think it needs a real good socket to go with. With volume fluctuations and a rather ill-fitting socket the knee can be pretty unforgiving.

Your Opinion: Have you used the 3R80? If yes, let me know as I would love to hear your opinion about this knee.