Hi y'all

[Josephine]

The prosthesis looks like this, Gringo. There is a metal cap on the end of the femur (thigh bone) and a metal tray on the tibia (shin bone). To provide the bearing between them, a plastic insert or spacer is clipped into the tibial tray. This comes in several thicknesses and the surgeon will use testers to see which thickness suits your new knee as it is when he has inserted it. That could 6, 9, 12 or 15mm. So his aim won't be to specifically address the leg length but rather to ensure a well functioning and properly tensioned joint. This may well lead so some leg length differential until you have the other one done.

 

[Gringo]

thanks, Jo. I was talking (online) to a guy I met on another forum before I found this one, and he has a 22 mm spacer in one leg,and an 18 mm in the other.

I have kept in touch with him because he is just about a month past his second TKR now, and lives right near where I am going for mine. A wealth of information. He's coming to the islands in October, in fact.

So, I guess I will probably have a list to starboard for a few months. That should be a new experience.

 

[Josephine]

Ah, they must have increased the range since I was working! It often happens.

 

[Gringo]

Well, that's interesting. I mean,22 mm is almost a full inch. I was already wondering where they could make up the difference when bone has gone away such as in my knee. They can only trim so much off, I think, and still have the surface to attach the prosthesis? So, the adjustable part of all this is the thickness of this plastic doo dad.

Is that the part they replace when it wears out?

 

[Josephine]

It is indeed. And yes, that's where the adjustment occurs. But it is dictated by the functionality of the ligaments around the joint, not the leg length.

 

[Gretchendz]

One of my spacers is a bit wider than the other. When we were looking at the xrays, I asked why he grinned and my OS shrugged and said said "Oh I probably sawed off a bit more bone on the second one." Made me giggle.

 

[Josephine]

I hope you mean thicker, Gretchen! That would be because the ligaments in the leg with the thicker one were slacker than in the other knee.

 

[Gringo]

Ah...well, then that brings up another question in my head. Which is seeming to keep a pretty good spinning motion going here about all this lately.

I am missing two of those ligament. The ACL and the MCL. I am guessing the other two are pretty much free to do what they want.


let me guess....bungee jumping is not on the approved list of hobbies after this?

 

[Jamie]

Gringo....I think bungee jumping is right up there with professional roller derby skating....probably not a good idea!

 

[Josephine]

Actually the cruciates wouldn't be 'crucial' (!) in your case, Gringo, as the surgeon would have used a "cruciate sacrificing" knee which has a peg in the centre to take over that function.

Plus the ligaments to which I was referring are the medial and lateral ligaments as shown here and the patellar ligament which is the bottom end of the quadriceps muscle. These three must be tensioned properly.

 

[Gringo]

Until you started explaining this to me, Jo, I had actually forgotten that the surgeon who did this thing called a 'slocum procedure' way back 31 years ago also removed what I believe he called the 'medial co-lateral ligament' along with the ACL.

Could that perhaps explain why my tibia and femur no longer line up vertically?

I can see how that peg replaces the cruciate ligaments. What do they do to replace the lateral ligaments so the knee doesn't open up sideways?

That is what originally happened, by the way. My knee got turned out to the side, ripping the medial lateral ligament, and the ACL, and messing up the meniscus, too.

Hurt like the dickens, actually.

Still does.

 

[Josephine]

Well, the collateral ligaments are supposed to be replaced with a graft if they are damaged beyond the point of repair. Otherwise the stability of the joint is compromised. I'm pretty certain that if he did remove it, he should not have left it without grafting in a replacement. The knee would have been very unstable and would not be lining up properly, though the subsequent damage from the arthritis would also have played its part.

 

[ship4]

Jo,
Good questions about the ligaments. Is the ACL removed as it travels thru the center of the knee joint? Just wondering.
Thanks,
Crystal

 

[Josephine]

Well, so far as I am aware, it's only removed if it's condition is poor.

 

[Gringo]

Jo, both my ACL and the MCL were completely removed, as far as I recall. There was no replacement. No graft.

I was fitted with a horrible leg brace from a hospital in the US called Lennox-Hill, and told that I would have to wear it for the rest of my life. I was 27, and working on the ocean, and that was unacceptable. I wore the brace maybe a year, until I built up the quads enough to function without it. Which I have done for 30 years now.

But I am having a real hard time since moving to the tropics and driving small boats that pound when you run them over waves big enough to launch them in the air. It really compacts the old knees. Backs, too, but that's a different issue.

 

[Gringo]

Hey, I suscribe to an online magazine that sends me info on new stuff every few days. I just got this one this morning, and it occurs to me that some of us may know people with permanent disabilities, or needing some fun PT, that might benefit from these gadgets.

Check this out:
http://www.glidecycle.com/

Its pretty cool, and can even be ridden by amputees.

Here's a link to a lady using it to rehab a hip replacement, for example:
http://www.glidecycle.com/physical_therapy.html

 

[ship4]

Well, so far as I am aware, it's only removed if it's condition is poor.

Does the ACL continue to travel through the replaced joint? I would think it would be damaged with the flatness of the platform and the spacer. Especially with the rotating platform.... Just wondering. I did some research and found this under the Zimmer website:
Stability
Ligaments are tough bands of tissue that connect the thigh bone and the shin bone. They stretch as you flex, extend and rotate your knee.

The cruciate ligaments are so called because they cross over each other, forming a cross when viewed from the side.

• The anterior cruciate ligament (ACL) keeps the shin from sliding forward.
• The posterior cruciate ligament (PCL) behind the ACL keeps the thigh bone from sliding all the way back.

The medial collateral ligament on the inside of the knee and the lateral collateral ligament on the outside of the knee prevent the thigh bone from sliding sideways when you walk.

When putting in knee implants, 99% of surgeons cut or “sacrifice” the ACL since it’s usually too damaged and tends to get in the way during surgery. To compensate for the ACL, the knee implant includes a tibial insert to provide stability.

The decision whether or not to sacrifice the PCL is more subjective, depending upon surgeon philosophy, functionality, etc. Some surgeons want to retain as much of the natural anatomy as possible. Others feel that a partially damaged ligament (as is usually the case) is unpredictable after surgery.

If the PCL is sacrificed, it must be substituted.

Best,
Crystal

 

[Gringo]

This is making me wonder how I have managed to get through a career on the ocean, and function for 30 years without a brace or the ACL and MCL.

Is this common? I guess it explains a lot of what's wrong with that x-ray I posted earlier.

 

[Josephine]

Gringo, can you explain exactly what you mean by ACL and MCL as it says two different things to me; Anterior Cruciate Ligament and Medical Collateral Ligament. Is this correct?

Crystal - what you have posted is correct and well explained.

 

[Gringo]

Yes, M'am. I meant Anterior Cruciate Ligament, and Medial Collateral Ligament. Both of those were destroyed in my left knee in 1977. I had surgery to remove them and clean out the knee in early '78. I remember that a 'slocum procedure" was done, and I had thought all these years that this referred to the removal of the damaged ligaments. I have just today looked up Slocum Procedure for the first time on the internet ( didn't have it in 78) and find out that it can mean the grafting of other ligament tissue. So I might indeed have some version of a Medial Collateral Ligament in there. Or not.

I was in a full leg plaster cast for a month after the surgery. That sounds like some serious knee stuff went on while I was asleep, doesn't it.