Knee Replacement Imbalance

What ligaments are tight? In 99% of TKRs the ACL is removed and in many the PCL is also removed. So one or both cannot be tight as they don't exist.

It sounds like you may have an alignment issue. Do you know what kind of alignment your OEM surgeon did? Traditional surgery would do a mechanical alignment which essentially means drawing a straight line down the leg. More recently surgeons have been attempting to restore the natural alignment of the patient, not an arbitrary standard. My surgeon did a Functional alignment; others are doing kinematic or inverse kinematic.

You say you can't get a straight answer from anyone. What exactly do the doctors you have seen say?

@steveinarizona

I've been back to my original surgical team many times with pain, swelling and with 3 dislocations. All they would ever tell me is that my knee is "unstable" and would never explain why. Not knowing why, bothered me a great deal, so I got a second opinion from another surgeon (at another hospital). He is the one who diagnosed my problem as a “flexure/extension gap imbalance”. You are correct, during my original surgery both my PCL and ACL were cut, but my Medial and Lateral Collateral Ligaments were left intact. It is these ligaments that second surgeon claimed get loose as I flex my knee. He explained, to maintain stability with my type of knee replacement that it is crucial that the gap between the Tibia and Femur remain constant as the knee is flexed and straightened. He did an examination that proved that the gap narrows as I bend my knee and the more the gap narrows the looser my Medial and Lateral Collateral Ligaments actually get. They get so loose that my knee becomes sloppy and unstable when flexed. The surgeon demonstrated this by having me sit in a chair and bend my knee just past 90 degrees. Then he took hold of my leg just below my knee and with very little effort he was able to move my lower leg all over the place. He went on further to explain that this excessive movement explains why my knee gets more unstable the more I flex my knee, He also said this why my knee is always swollen and painful. Unfortunately, he refused to speculate on how or why my knee got this way. I’d like to know how this happened, so I can move forward.

From your post it sounds like the second surgeon knows what he does. Okay...he won't speculate on how it happened; I understand that doctors don't like to throw their colleagues under the bus.

But will he fix it and what is the fix? Is it repair to the ligaments rather than a revision of the implant? I would not want the original guy anywhere within 25 yards of me. But this surgeon might be able to help.

This may sound crazy, but I have no grudge against the surgeon who did my knee replacement surgery. I am one of those unfortunate people who's body seems to reject anything foreign that puts into it. I also am allergic to quite a few different metals, many of which are commonly used in knee replacements. My allergy to nickel is off the chart. I made my original surgeon aware of my nickel allergy and he had my blood tested. He found that I was allergic to virtually every single knee replacement made and I'm not joking. So he reached out to the different manufactures and found one (Smith and Nephew) that agreed to make me a custom knee replacement out of metal (zirconium oxide) that I wasn't allergic to. Then he got it through FDA approval. The whole process took about a year. Before I went to him I researched his background, read all of his reviews and I personally know one of his PAs on his staff. I also know that I am the only one of his patients that has had a knee dislocation. I'd still be going to him but he doesn't accept Medicare. In spite of all his efforts, sometimes s**t happens.

As for the second opinion surgeon, I was all set go with him until he uttered the words "there is no such thing as a metal allergy".

It's my current surgeon and his team of doctors that I'm not trilled with. The second time my knee dislocated he was assigned to my case because the first didn't accept Medicare. On paper his credentials are excellent and that's where it ends. He's the one who won't say anymore than "its unstable, you need a hinged knee replacement" and won't explain why. I'm definitely NOT using this doctor for anything.

I'd just like to know the possible reasons why and how I ended up with this Flexure/Extension gap imbalance before I go looking for my next surgeon. Did the original tibial or femoral component get installed at the wrong angle, did they select the wrong spacer pad, did something move or shift? I just can't believe that my Medial and Lateral Collateral ligaments are a fault (stretching or weakening), if that were the case why doesn't my knee get unstable when straight?

@skybig

Very good explanation of issues relating to gap imbalance which is the cause of my mid flexion instability and severe lateral pain due to soft tissue impingement.

It took 4 opinions regarding my severe lateral side pain post TKR 12/23 to have my current surgeon explain gap imbalance as well as possible rotational problems with my implant.

I had a partial TKR 7/25 to attempt to correct this by replacing the insert only with a semiconstrained insert. I knew that this was a 50-50 chance and I wanted to avoid a full revision. It did not work.

I am having a full revision in 10 days on 4/28. The plan is to change the femoral component only if this will resolve the gap imbalance to the satisfaction of the surgeon. If that will not work he will install a DePuy hinged implant. I asked about using a less constrained CCK implant but his opinion is that at this point the hinged is best. Hopefully this resolves the severe pain for the last 28 months.

As to comments about the competence of the original surgeon, I believe that mine did not perform the TKR properly. I have posed that question to several surgeons who have examined me. They will not comment or throw one of their own under the bus.
I fired that guy and moved on.

@dbduffer

Sounds like you and I are in similar boats. When you have your Femoral component changed on 4/28 are they going to let you heal and go through rehab or is the surgeon going to decide on the spot that the new femoral component won't work and move right into the hinged knee replacement? Meaning you won't know until you wake up to learn what they did?

The first year after my TKR I too experienced a lot of pain due to some soft tissue getting caught up in the joint, so the surgeon scheduled me for a synovectomy. Two week before the date, I dislocated my knee for the first time. They rushed me into surgery and did the synovectomy (removing the synovial lining and some soft tissue), replaced the pad and sewed me up. That greatly relieved my pain. I get some pain now, but not bad enough to do anything about. The plan was to go on happily ever after, but went on to dislocate it two more times. Ask your surgeon about having the soft tissue removed when they do you revision.

I wish you all the best!

I have had two diagnostic injections to the popliteus. They were not very conclusive and provided less than 12 hours of partial relief. The sports med doctor, my surgeon and I agree that there is a mechanical problem with the implant. It is impinging/irritating the popliteus and possibly the gastroc and/or other soft tissue which causes a lot of pain.

If I thought that a politeal release would fix me I would do it. The implant feels loose, makes a lot of noise and there is too much laxity. I agree with the surgeon that the extension/flexion gap is not correct and this needs to be resolved.

This is surgery number 3 and I do not want to do it again. He will initally check the femoral implant to determine if a larger one will fix this. If this might work he has to determine if the tibial tray is sloped properly or can be repositioned to work with this procedure. If not it is a hinged implant.

I am giving the surgeon permission to do whatever he needs to do during the operation. He is an experienced revision surgeon and that is the best I can hope.

Best to you as well.