too young?

[klinger]

Good morning all,cant help but notice that many of the threads posted seem to be regarding the age of the patient needing a TKR, I,m just 50 and will be having my right knee done in feb 08.
My consultant said it definitely needs doing,however it was up to me as at 50 he said its rather young.So my question is...is it too young because the TKR will have to be done again? and is the second opperation more complicated than the first.
Also it would be interesting to know what part of the artificial joint wears out and why couldnt that surface just be renewed.Could this not be more down to a lack of engineering developement rather than a lack of medical advancement I only ask the question because we,re hardly talking rocket science here!
regards Klinger

 

[Josephine]

Hello, klinger. What excellent questions you ask!

Well, the short answer is that no-one really knows the full longevity of the current knee replacements therefore, there is a tacit reluctance on the part of surgeons to operate on patients who will expect a longer service from the prosthesis than the data that exists. Currently that is about 10-15 years. However, the number of patients still going strong on replacements far exceeding that grows daily. But what also is increasing is the technology and quality of manufacture, testing and follow-up. For instance, for every knee replacement that is done in the UK, the operating theatre staff fill out a form supplied with the prosthesis complete with patient's name, age and hospital number, which hospital and surgeon, date, and the stickers off the 3 or 4 implants that carry all the data of that item, bar code etc. This is sent to a central data base and any problems the patient experiences with the replacement thereafter are relayed back to the data base. By this means, specific and reliable data is being built up to demonstrate the reliability of the different types of prosthesis and it's longevity.

Current statistics would tell us that the implants are a lot more reliable and long lasting than we would have imagined. In the hip surgery forum, I have placed a sticky entitled "40 years life span for a hip replacement!!". This one was implanted at a time when we were convinced that they wouldn't last even ten years never mind any more!"

So, what I am saying (in a round-about kind of way) is that the surgeons are still naturally cautious about recommending joint replacements to younger patients. After all, pain notwithstanding, you really can't beat your own joint. A replacement is always second best. You need to bear that in mind. But there always comes that point where the 'second best' option will outstrip the one you have. When you get to that point, you will know and be happy to settle for the limitations it imposes for the advantage of being pain-free.

As regards which bit of the replacement? Well, nominally, it would be the plastic insert in the tibial component. In other words, the concave bit. As you can see here, there are three bits, the larger one on the femur, the smaller one in the tibia and the plastic insert in the tibial component.

Essentially, the tibial component can simply be replaced but it is still tantamount to the original, major operation. However, there may be other or different problems such as loosening.

In short, it is rocket science and it's not! It's not exactly like changing the brake linings on your car!

The knee is a very complex joint and the surgery of it is complicated. That's why some surgeons specialise in it, because they do little else and therefore get to know the knee, its structure and mechanics like the back of their hands!

I hope this explains it somewhat for you.

 

[klinger]

Hi Josephine,thanks for that excellent response to my question.My brother gave me a cutting from the sunday mail recently all about a new metallic insert that rests upon the tibia,apparently this has given a lot of relief to many OA sufferers from across the pond,do you know anything about it?
I,m actually looking forward to having my opp, the only reservation I have is, if this is the new all singing all dancing thing to get done I dont want to be saying" I wish I,d have waited" do you know what I mean?
Anyway nice to talk to you again regards klinger

 

[Josephine]

Well, as I said elsewhere, in my opinion, I'd sooner settle for any implant if I had a surgeon that was extremely experienced in using it over the implant of my choice and a surgeon that had only used it a few times. Implant failure is extremely rare and of the complications that arise, I would guess that about 70-80% are more likely due to other reasons such as loosening, pain from faulty alignment or infection and those are due to poor technique, nothing to do with the implant itself.

As regards the choice - not sure we get much of a choice here in the UK. Usually it's the GP that chooses the local hospital and the surgeon there that chooses the implant. But I would say unicompartmental are without a doubt, the best type to have though they are not suitable for advanced conditions. After that, the rotating platform is pretty good as it allows more rotation that there. But by and large, all prostheses are pretty good and with proven track records. I really wouldn't worry too much about it.

I've heard of the tibial resurfacing but it's very new. It came from the same principals as the Birmingham hip resurfacing. These principals often don't transfer from one joint to another that well. I'll reserve my judgment on that for the time being.

 

[JonInce]

I'm only just 47 and about to have a TKR of the left knee in January 08. My Consultant said i had the knee of a 70year old and didn't know how i was still walking let alone performing all the activities that i do.....but i am concerned over the longevity of the new joint. I am probably going to have the AGC unit from Biomet.......When i read up on this unit it has been used since 1983 about the same time as i had my original skiing accident which damaged the knee in the first place.......this means nearly a quarter of a century of this type of knee replacement !.......What are the issues surrounding technology advances in TKR's I understand about cartilege replacement and the difficulties there with rejection and or friction problems. I want to maintain an active lifestyle and as the years have prgressed i guess pain management has adapted to the condition my knee is in. I also changed my excercise regime as time progressed and for example i row but i can't run, i swim but can't take an extended walk in the lake district. I use the swimming to keep me fit for Scuba diving......I gave up skiing though i went twice more after the original accident on march 3rd 1983........I gave up squash in 2003 so basically i do non load bearing excercise but still my left thigh wastes away because i can't isolate it to strengthen it. In an attempt to get fitter prior to the operation i am swimming 6-8 miles a week and rowing 50km (a concept II rowning machine not on water...) I also ride a static excercise bike for an hour at a time in Cardio mode.........So if i go ahead with the TKR and i am advised to do so........what sort of regime am i going to have to consider to get the stregth back in my left thigh and surrounding muscles post op. I have already been warned that failure to maintain the excercise will result in seizure of the knee which will end up worse than not having the TKR in the first place......what to do ?

 

[Josephine]

There's no doubt that committment to an intensive rehab will increase your chances of long term success but I really would be too pessimistic about the longevity of the implants. As you have discovered, they have a pretty long history now and are a lot longer lasting than ever was originally expected.

As I have said before several times on this forum, by far the biggest problems with 'failure' (i.e. unacceptable outcome) are issues surrounding infection and loosening and both these are down to poor surgical technique, nothing to do with the prosthesis. Wear of the plastic component is more of an issue in hips do to the spherical nature of the component, not quite to much in knees. Other failures such as breakages of the components are so rare you really don't need to worry about them.

A real problem I see with garnering information from the internet (as I presume you did) is that most of it comes from the manufacturers' own websites which are naturally going to emphasis their own product's good points and their competitor's bad points. I would therefore be circumspect about taking them at face value. If prostheses were proving the slightest bit problematic then surgeons wouldn't be using them. Remember they have to live with the results of their surgery for the rest of their professional lives and often after so they are unlikely to continue using a product in which they don't have confidence.

The final analysis of all this is that before you worry about the type of knee you will have, first be certain that you have a surgeon who has a significant experience using it and who also has a good history of acceptable outcomes. You can only find that out by asking around and talking with your GP who will know the local surgeons' records. Having found out about that, just go with whichever prosthesis he uses.

 

[Pattipoo]

Hi...this is my first post.....will read and post more later. Just wanted to say hello and tell you that I'm also having TKR on Jan. 7, 08. I'm 51 and was told that I have the knee of an 85 year old....that's ALWAYS great news, huh? I'm a little anxious about it, who wouldn't be?!, but I'm excited about it, also...I'm sick of the pain. My son played college football, has had several surgeries....the team's head ortho. guy is performing my surgery, he's opted for the porcelain/ceramic knee. I'll read along and ask questions a little later. I wish you all the very, very best success with your surgeries.
pattipoo