Disclaimers first: I’m not seeking medical advice. This doesn’t even apply to me - it’s my sister’s knee. She’s under a doctor’s care and she didn’t ask me for advice.
All that aside, now, my sister is 51. When she was a teen, she did something that required knee surgery. I don’t know the specifics because I was living across the country at the time. But apart from a scar, you’d have never known she had the surgery. Until recently. For the last year or so, the pain has been increasing to the point where now she often can barely put weight on the affected leg.
She’s seen at least 2 orthopedists and both have told her that she’s too young to get a knee replacement. The last shot she got lasted all of 6 hours, so this isn’t your run-of-the-mill sore knee. She needs to get it fixed.
Which leads to my question: Why would they tell her she’s too young for a knee? They claim it would only be good for about 15 years - can a knee replacement not be replaced later? Would they have to amputate when the knee fails?
I seem to recall that my grandmother got new knees when she was in her 50s, so has something changed in the last 30 years? Anyone here have knee replacement experience?
As long as your sister can walk they don’t want to do the replacements because they will probably wear out in her lifetime. The devices haven’t been around long enough to know how well a second replacement will work. Doctor told me the same thing when I was 50, said I’d need it eventually, but actually my knees haven’t gotten much worse in the past 10 years. Can’t say that for the rest of my body though.
A former girl friend of mine had a knee replacement done at 53. She destroyed her left knee while in the Army when she was 20. She had 3 surgeries then and another at 45. He knee was toast and she was tired of using crutches to get around.
First-time knee replacement surgery is relatively simple, straightforward, with good outcomes and low risks of complications for the typical patient.
Second-time knee replacement is much riskier, with longer recovery time, more chance of poor function/chronic pain afterwards, and high risks for infections which are extremely hard to treat and may result in a fused knee or even an amputation. So surgeons like to avoid these types of surgeries wherever possible, by delaying the first surgery for as long as is feasible.
Hmm, Sounds like we need to get an engineer in there the first time. Some snap-in, snap-out bearings, maybe a little zerk in the knee pit for topping up the lube, turn additional knee replacements into a 10 minute tune-up.
Well, biomedical engineers (many complete with MD-Ph.D degrees) have been working on this for a looooong time, with mixed results. Perhaps with a fusion of stem cells, CRISPR, and nano-bots, we’ll be there soon.
Seriously, I saw a guy with “failed knee surgery” syndrome just today. He can bend it about 15 degrees, but he’ll never dance with his cellie.
Ya, I’m looking down that barrel myself. I’ve had two partial shoulder replacements that have about a 20 year life span after that the doc told me I’ll have to get total replacements. Which of course are maybe worth 20 years themselves. The down side is I’m 34 so I’ll be 75 and looking at my third round of replacements eventually.
That being said I couldn’t move my arms or sleep prior to my surgeries so I’m still extatic with the situation I’m in. I think it’s about how bad your current situation is and how much longer you have to probably deal with the pain. For me the odds of a great recovery now we’re high which 90%+ releaved my symptoms and hopefully good things happen in the next 20 years to make that one a lifetime replacement.
Why on Earth, with all the engineering plastics, micro-machining, 3-D printing and a shitload of metallurgy, CAN’T someone come up with an (admittedly complex) frigging hinge?
I’m going to guess the problem is not in the implant design, it is the practice of pounding metal spikes into cut-off bones that cause the failures.
Anybody trying to get the bone to grow over a mesh which has new load-bearing surfaces?
I’m thinking of a mesh “cap” over the bone. The mesh contains a hard top plate which forms a mating surface at the “top”
One cap goes on femur, another on whatever is on the lower end of the knee.
No more cutting off bones - maybe grind down the ends a millimeter or two for the new bearing surfaces.
It turns out that engineering a joint that is flexible but not too flexible that can withstand daily wear for decades isn’t easy. Mother Nature gets around some of the problem by having the joint composed of living cells that (at least in theory) do a lot of housekeeping/minor repairs every day. Our engineers don’t do that, they try to build something that can withstand that wear without daily micro repairs.
Then you have to try to get the organic and inorganic bits to play nice with each other, preferably without alarming the patient’s immune system - you know, that system that has spent the last half billion years evolving to detect and eliminate foreign items in the body.
And individuals vary - almost 40 years ago my spouse had an artificial ankle installed. He’s still walking on it. That is an unheard of service life for an artificial joint, yet his body has not rejected it and no component has broken. Other people have had much more advanced artificial joints fail much more rapidly. Why? Who knows?
For my partial replacement I have a cap on the ball but they just clean out the socket. That titanium will erode my socket in the next 20 years and then I’ll need a new socket. Right now the sockets are a polymer that has load bearing restrictions (~200 lbs at 5% body fat I weight 250 so if I caught myself falling I could punch through the socket) hopefully this is where there will be some revolutions in the next 20 years.
Replacement knees can go 15 years but can also fail as early as 8 or sometimes even less. Most doctors around here will call the “average” 10 years which could - maybe - mean three replacements depending on how long she lives and wants to be active. Usually knees can easily be replaced twice; my late FIL had one done twice and one once. But having enough good bone for a third bight at the apple seems AFAIK pretty rare. Hence the desire by orhtropods to stall you off as long as they can.
Now the amputate ---- that comes more from the operation being botched, not so much a replaced replacement. My Dad, his first knee, the doctor left so many bleeders behind he almost lost the leg and his life. Thank God the chief nurse in his department was an old girlfriend of mine who made sure he got just what he needed to pull through; even at the risk of her own career. In other words, tons of knees get done but like any operation their are risks. And a lot of those risks involve ending up with the nickname “Stumpy”.
All in all I would say think and consider and if you (she really) wants it, fight tooth and nail and get it. But understand you may not have the perfect result I would wish for her.
10 years?!? My orthopedist told me 20 years for a knee replacement at best. I will eventually need one, maybe two (bad knees run in my family – both my mother and uncle had double replacements).
I’m 56. My ortho won’t consider me a candidate until I’m at least 65 (“Medicare will pay for it, that’s why everyone waits”). The other reason, as others have already stated, is because doctors don’t like having to replace the replacement; ergo, the older you are when you get the initial one, chances are it’ll outlive you.
I walk unaided, if painfully at times. I refuse to eat NSAIDs for breakfast because I like my liver, thank you. Shots do nothing for me, but as my ortho says, “There’s nothing else I can do to help you.”
One of my friends had a hip replacement in her 40s. She’s in her early 50s now and was recently told she’ll probably have to have it replaced in a few years, and it won’t be an easy procedure.
The pics i saw of replacement knees (I have osteoarthritis) show massive modifications to both sides - the lower one actually does have a wedge that, apparently, goes into the bone.
There isn’t much bone in that joint to begin with.
What’s left after removing those pieces is going to be a very poor candidate for much of anything.
My idea of putting caps over the bone to hold the weight-bearing pieces would save most of the bone.
Maybe use some scanner (CAT, MRI,?) to create a 3D model of the bones and cast/machine caps to fit.
If the bone can be convinced to grow into the lateral portion of the cap, you have something akin to a natural joint
Even if it fails, does not leave the bone mutilated as do the current replacements.
My new knee involved making a template using 3D technology to decide exactly where to make the cuts so the surgery could be done much more quickly and without general anesthesia. The implant has replaceable components so some kinds of failures won’t involve a new replacement. My doc said he would be surprised if my implant didn’t last 25 years. I think there is a LOT of difference among orthopedic surgeons on the techniques that are used. I also think I got lucky.
A younger member of my extended family is an orthopedic PA at an area hospital. One of the orthopedists with whom he works is known the sports business as A Knee Guru – he’s operated on everyone from professional quarterbacks to high school soccer players.
We discussed surgery and my knee. I told Family Member my saga and what my ortho told me (it’s upthread).
Family Member said, “They’ve made a lot of improvements the last few years, but you’re not an athlete. Osteoarthritis is wear and tear, and what they basically do in a replacement is ‘sand’ down the arthritic parts of the joint before putting it back together with metal and pins. So yeah, the doc I work with would rather have you wait until you can no longer, literally, walk before giving you a replacement because he’s not going to want to replace it again.”
I’ve seen other people give ideas, but you seem to know the most as a doctor yourself. What is the reason for the difference? Is it that more of the knee wears down, and they don’t have as much to work with to put the replacement on?
Also, have they considered making something that doesn’t bend quite as well, or that attaches on the outside and such? Something that could work as a secondary knee replacement after the first one?
My husband had a knee replacement this year and he’s only 51. He had an injury as a teen, first scope at 20 with more along the way. He could only walk very short distances with a brace and a lot of pain and we decided not to wait longer because he has spine issues (3 surgeries including fusion) which will likely deteriorate further and impact his mobility significantly as he gets older. In his case, being able to walk pain free now is more valuable than whatever happens 15 years down the road when he’ll need a second knee replacement.
I am only a humble primary care doc, who takes care of patients before and after their knee surgeries. There are many fine orthopedists out there who could wax far more eloquent than I on the difficulties with repeat knee replacement operations. I tried to pick the brain of an orthopod friend of mine, but couldn’t find [del]his brain[/del] him.
Biological units are complicated. Just normal wear and tear and apoptosis (programmed cell death) means things go to hell over time even under ideal conditions. But add significant trauma like a few decades of hard use, an injury or 6, and that major trauma of having your knee opened up, sawed upon, chiseled, drilled, ground down, hammered, glued, stapled, etc. and there are consequences. Reactive inflammation, fibroblast formation which leads to scar tissue, diminution of blood vessels in the area, slow bone resorption and deterioration in the area, adhesions causing everything in the vicinity to stick it itself and its adjacent tissues, microclots and microhemorrhages, and on and on and on.
And that’s after the first surgery, with a (relatively) pristine knee, and with a pretty good outcome anticipated. Now let that mess stew for another 5 or 10 or (if lucky) 30 years, and try to revisit it with a second replacement/rehab job. Structures are surrounded by scars, shrunken, more atrophic, and difficult to even identify, much less tease out from their surrounding structures. Adhesions everywhere, brittle and barely viable bone underlaid by slightly less brittle and a bit more viable bone underneath which may respond to resurfacing by just packing it in, poor blood flow, and all the old hardware that must be yanked out and replaced, leaving a messy, scarred up void which needs to be filled just right to work at all, much less work for years. Subsequent healing is slower and not as complete, immune defenses can’t penetrate the area as well as they used to, raising the risk of infection, further tissue death, etc.
Biomedical orthopedic engineers ponder these issues continually, trying to improve things for every step of the way. Brilliant professionals are constantly floating new ideas based on new technology and techniques, and are getting better outcomes than before, but it’s still a bloody mess and progress is incremental and the devil is in the details, and the details number in the millions, on a cellular level. New surprises occur with every new technique, device, procedure.
Yet we persist, as we should. Excelsior! Try again! Try another new idea! We shall not bend our knees in pursuit of more readily bent knees!