A living replacement knee to be tested in clinical trials within five years | Hacker News Reader

A living replacement knee to be tested in clinical trials within five years

engineering.columbia.edu

153 pointsgeox72 comments

As a child I had Perthes disease (a rare, degenerative disease of the hip), and it has given me pain for 3 decades now. I've known that a joint replacement is in my future for essentially my entire life, and I was told as a kid to wait until the technology was better. There has long been talk about biological replacements, but nothing seems close to panning out, and the standard still seems to mean sawing off parts of your bones and replacing them with metal. The biggest change seems to be in the plastic parts and the addition of ceramics in places. My understanding is that both hip and knee replacements have benefited.

My father has had both hips replaced in the fast few years. Both surgeries were very successful and he has retained full hip joint function. He no longer has pain in his hips.

His surgeon used an approach that minimised damage to the muscles in the area. If I recall correctly, this meant he gain access to the hip joint via the posterior side of dad's upper leg, and went between muscle and tendon, rather than needing to cut muscle to get to the joint.

I don't know if I'm remembering correctly, but dad healed up pretty quickly.

From what I understand joint surgery especially knees and hips have a great ratio of benefit to cost

hip normally works very well - it's just a ball and socket joint. knee is a bit more tricky.

I used to roll BJJ with a 50-ish year old man. As a teenager he suffered a debilitating car crash and hip replacement at the time, resulting in his having a cane until his second replacement circa 2020. This allowed him to walk cane free and practice marital arts.

The technology is there for hip replacements, it would seem.

as i said, hip replacement normally works very well. my 80+ mother had two after two bad falls, both worked really well physically, but she went off the rails mentally after the second. apparently there is a theory (sorry, can't find link) that doing surgery like replacements releases a lot of fat into the bloodstream that can drive you nuts. that seems to be what happened to my mum.

i don't suggest anyone should not get a replacement based on my non-medic and probably wrong information.

>Postoperative Delirium and Postoperative Cognitive Dysfunction in Patients with Elective Hip or Knee Arthroplasty: A Narrative Review of the Literature

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8878498/#:~:tex....

Practicing marital arts is serious business, this is surprising!

Very true, functional hips are very important in the marital arts!

You just have to make sure your spouse is ok with you practicing with other folks.

That would be extramarital arts, sir.

Thanks for sharing, and goddamn, that sucks.

I got one hip replaced in my thirties with titanium and ceramic. I am so glad I did it. I can't run too much but, beside that, I got back entire mobility after couple of months. More than 10 years have passed and it's like not having a prothesis. Ceramic was suggested by doctor as it lasts longer (though it's more fragile in case of accident).

Thank you for sharing that - it seems to be the rule that everyone I've talked to who has the surgery recommends it, though I have not known anyone who had it done in their 30's. My understanding is that ages are averaging down for a few reasons. I had a co-worker who had it done in his early 40's back at a time when that was nearly unheard of. He wore it out after 22 years but also had a successful revision. That was before ceramics or newer plastics so there's reason to believe that the current ones might last much longer, but it is still daunting facing the prospects of multiple surgeries; something I'm sure you must have grappled with.

For people doomed to this fate like myself, please try cycling. My mom has had numerous knee surgeries due to lack of proper exercise and being overweight. My knee issues started at 15, so presumably it’s genetic. When I started cycling regularly at 24 the problems receded almost entirely. I doubt this will completely prevent the need for surgery later in life, but I’m glad I’m doing what I can.

Swimming is good too, even more gentle

Doing nothing is even more gentle; that's not exactly the idea.

“Low-impact”

The idea that swimming is better than cycling because it has even less impact is simply invalid. The low impact of cycling is more than low enough.¹

(Outside of falling down and hitting the pavement, of course!)

I would say that if all you do is cycling, you should add some more load-bearing exercise, like weights, and a bit of running.

You should not be worried that cycling is too high impact and go for swimming for that reason (though there are great reasons to swim, and nobody should be discouraged from that!)

＿＿＿＿

1. Except for someone with a serious injury that they are treating with pool exercise, or a member of some other special population.

You're being obtuse. Parent clearly meant gentle as in "lower impact", which really is the idea. Swimming is a great exercise option for joint health (and in general).

Nope; you need load bearing. And even some mild impact.

Lower impact being better than high impact doesn't imply that even lower impact is even better.

https://en.wikipedia.org/wiki/Bone#Remodeling

"Repeated stress, such as weight-bearing exercise or bone healing, results in the bone thickening at the points of maximum stress (Wolff's law). It has been hypothesized that this is a result of bone's piezoelectric properties, which cause bone to generate small electrical potentials under stress."

Swimming is beneficial, and is a great complement to load-bearing exercise.

This is a much better response than your upstream contribution.

Swimming may or may not be appropriate.

Swimming, generally, is pretty poor lower-body exercise. Most swimmers have very well-developed upper-body strength, though favouring back and torso generally.

Legs get comparatively little workout, though for competitive swimmers starts (diving off the blocks) and turns (kicking off the wall) are periodic explosive strength.

Swimming can and does lead to joint problems in many cases, notably shoulders (for most strokes) and knees (breastroke or "frog" kick). The human anatomy isn't really designed for dragging itself through water, and repetitive stress injuries can emerge. The leverage effect of even a small effort exerted at the hand or foot transferred to the elbow/knee or shoulder/hip can be stunningly large.

There is the option of "aquasize" or "water walking", which can be useful as rehabilitative exercise or for the morbidly obese. This is water-assisted movement, though, not swimming per se.

Mind: so long as you're mindful of limitations, and swimming is both convenient and useful, it's a great exercise and a useful training tool, or goal. But it's possible to hurt yourself in all kinds of ways.

A useful rule of thumb is that mild soreness in muscle after exercise is generally OK. Pain in joints or connective tissue is not, and is a strong signal to back off, with total rest for days or weeks often required.

(Source: long-time competitive and recreational swimmer, some-time fitness fanatic.)

> knees (breastroke or "frog" kick)

Anecdata: My knee consultant specifically banned the breaststroke kick if I go swimming (but then my knee is a disaster area and pending a replacement.)

I know quite a few competitive breaststrokers who developed knee problems in their later teens, so, yeah.

Flutter or dolphin kick, with or without fins ("Zoomers" are particularly useful) should be safer, and actually is a reasonably good lower-body workout, particularly in conjunction with strength training (squats & deads notably).

From what I read cycling is better, at least for cartilage, check out the video of this doctor - https://www.youtube.com/watch?v=6PNBjKJ9hxQ. He also talks in other videos about the force you get on the knee from a push motion, versus a kick motion, with the kick motion exerting more force.

My mom is also overweight and having the resultant joint issues because of it now that it's been decades. I feel bad, because it just results in pain, which makes her move less, and it just becomes a vicious cycle. Some things provide temporary relief, like steroid injections, but the core issue is still there.

Never stop moving, if you can help it! Mobility is so important.

I was asking a friend about this just yesterday. My left knee is starting to hurt, including while walking. I use the bicycle as my main mode of transportation, and I was wondering if it's good for the knee or bad for it.

The general assumption is that bicycling is good for it; it has negligible impact, and the motion will keep muscles and tendons flexible and increased blood flow is good for healing. Particularly use lower gears and 'spin' faster, so your pedaling rate is 80-90 RPM (i.e., don't be pushing hard on the pedals at low RPMs). This is both most efficient and keeps joint loads lower.

Please note the "assumption". Be sure to ask your doctor about your specific condition, as no one here including me, has any idea what is your actual condition and what the effects would be.

Hope your knee gets better soon!

A lot of what I do is low RPM high torque climbing. That’s the kind of exercise that builds strength in the gym (fewer reps at higher weight) so I expect it builds my lower body strength better than spinning.

It's better for strength but worse for the joints.

It’s been a net positive for me

I think it's not a binary thing, and depends on a lot of things, such as your age, the strength of your joints, etc. Pedaling a bit slower than regular spinning speed, for most healthy people, probably helps improve your strength without overtaxing your joints. Pedaling a lot slower, however, could cause problems. Also, there's the issue of long-term damage: you might not notice until years later that an activity was hurting you. (Note I'm not claiming this about mashing specifically, I'm not an orthopedist or other medical professional.)

I tend to pedal slowly, though as I've gotten older my cadence has increased. Basically, find what speed works for you I think: if you're having knee pain, try increasing your cadence with a lower gear.

Sure, if you're doing that for a particular reason such as you mention, great. Beginner cyclists also tend to pedal with a much slower cadence.

But it is definitely not the fast way around the track or down the road. For almost everyone, the 80-90 or 75-95 RPM cadence is most efficient. Slower will exhaust the muscles sooner, and faster (except for sprints) will squander energy on ineffective motion (as in force that doesn't get to the wheel).

Also, unless you are doing such low-RPM/Hi-torque levels that you literally fail in 6-20 strokes, you are doing closer to a bodybuilders' bulk-up routine. Going to failure in few sets builds peak strength. Doing more sets doesn't build peak strength, but does build more bulk; the levels of low-rpm pressure and "reps" of pedal strokes done in cycling for tens of minutes are definitely in the high-rep/low weight gym regimes. To really augment your strength, better off doing weight workouts with leg press, knee extension, knee contraction/curls, and squats. It definitely helps cycling performance.

I would recommend doing lunging exercises as well as the flamingo stretch. When the tendons/muscles around my knee hurt doing just 2 minutes of lunging will fix them up.

Backward sled pull or just pushing a treadmill in reverse with the power off, ten minutes, 3x a week. Check out knees over toes guy on YouTube. Former world cup mogul skier and treeplanter of a decade with the toll of all that.

Also, touchdown squats. These and backwards sled push totally and quickly fixed fairly significant knee pain I was experiencing.

https://www.youtube.com/watch?v=Nj6c9ELsquY

What about rowing using a C2 ergometer or similar?

Should be good, so long as there are no obvious signs of injury or pain in the involved joints (ankle, knee, hip).

Interesting, I bike regularly and feel it has exacerbated issues with my leg tendons in general, around my knee, causing pain!

Try getting a bike fit (or just watch some videos to learn how to fit yourself). If it’s bad enough it might only be addressable with physical therapy.

Just here to remind people - biking with your seat too low is quite hard on knees. Folks typically recommend raising the seat until your leg/knees are almost straight at their furthest extension, but not quite.

Hard seconding this, it’s so important. It’s really easy to get the seat height vaguely correct, there are a ton of YouTube videos explaining how to do it.

That's what I detest about Youtube. Murphy's Law says I'll manage to pick the videos that are wrong.

The way to combat this is watch like 5 and follow the wisdom of the crowd.

Be particularly careful here if you are tall and if that's the case, get the right bike for your height.

I got a professional bike fit. Definitely worth it if you ride a lot.

Specifically, with your shoes on, seated without dipping either hip, your leg should be slightly bent when your heel is on the pedal and the pedal is at the lowest point. Yes, all of that detail matters! A full bike fit is best but the above will be a good start.

How much and often did you cycle?

Cycling is good. I've also found boswellia and curcumin supplements to be surprisingly effective for the arthritis symptoms.

Does this bypass organ rejection or might this still require continual immunosuppressants? The only clue to this is the following:

> Since cells are required to regenerate and maintain this living implant, the team will create two versions of NOVAJoint: a version that uses patient’s own cells and one that uses donor cells.

Presuming that the donor cells do require immunosuppressants, this leaves the question of "will the version that does not require donor cells require immunosuppressants, and if so for how long?"

I guess the version with donor cells is fine if one is already taking immunosuppressants because of some other reason.

This seems to be a DARPA program kickoff with ambitious goals, not a press report of published results. I think a bit of cautious but enthusiastic skepticism is warranted here.

It feels like science is progressing in all aspects except spinal disc replacement/regeneration.

https://www.healio.com/news/orthopedics/20230209/discgenics-...

Looking forward to this. My guess though will be that only methods that require a "subscription" will see the light of day. As in, things that require repeated applications, life long medication etc.

Unfortunately, repeated injections cause scar tissue build up. This is the main reason I've steered clear of any injection based therapy. They work fine at first but over time accelerate degeneration.

Hair loss science sure isn’t.

I’m under the impression that there are multiple effective treatments for hair loss

Yeah, some of them work, at least for some people. Almost every male in my family, and all the direct-line male relatives on both sides, went bald by their late twenties. Maybe I just got some good dice rolls and so this is a tiger rock, but when I noticed my hair just beginning to thin around age 23 I got on finasteride and have been taking it ever since. I'm 36 now, full head of hair, and if anything my hair grows fast enough that it's kind of annoying how often I need a trim.

With problematic/risky side effects though? (https://en.wikipedia.org/wiki/Finasteride#Finasteride_for_an...)

Meta-studies seem to indicate that the preponderance of the evidence is against, not for, scary side effects. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481923/

Not far enough with HIV. Yes we have pills that significantly expand lifespan (by up to 30-40 years), but they make you severely prone to cancer and your immune system never really has a full chance to recover making you prone to all kinds of opportunistic infections. We really need a cure and I don’t think we’re moving fast enough with CRISPR based solutions. We know how to excise the HIV, we know how to add the CCR5 gene to T cells. We need to move faster.

I’ve been so looking forward to this tech

I had a near complete menisectomy at age 16. Always told myself that by the time I’ll need a replacement, the tech would be good enough

I’m now touching 36 and can start feeling my knee breaking down. Hopefully this will be commercially viable within 10 years

Incredible stuff. I could use a few new joints myself.

> the team will create two versions of NOVAJoint: a version that uses patient’s own cells and one that uses donor cells.

If the knee replacement uses the patients cells, won't the new knee be effected by Osteoarthritis as well?

if you use donor cells there's a chance of rejection. patient cells will probably limit bad outcomes

Reply on news.ycombinator.com