Thursday, February 16, 2012

What is a pseudotumor and what is the occurance of them in post hip patients?

Pseudotumors are a rare but important complication occurring with all types of hip replacements.The true prevalence of pseudotumors is debated.Potential causes of pseudotumors may include foreign-body reaction, hypersensitivity, and wear debris.The conduct of clinical trials on the incidence, causes, and treatments of pseudotumors has been inadequate as few investigators have used a randomized controlled design to compare various implant types
another definition>
Pseudotumors are sterile inflammatory lesions found in the soft tissues surrounding metal-on-metal (MOM) and metal-on-polyethylene hip arthroplasties. In patients with MOM hip arthroplasties, pseudotumors are thought to represent an adverse reaction to metal wear debris. However, the pathogenesis of these lesions remains unclear.

Another tidbit

A recent study conducted in Canada on the occurrences of pseudotumors showed that the incidences less than .1%.
I like this description below written by  by Patricia Walter :

Patients and prospective patients are always concerned about the complications that could occur after a hip resurfacing surgery. The typical problems include femur neck fractures, dislocations, loose acetabular cups, improperly positioned acetabular cups, high metal ions, infections, pseudotumors, ALVAL and metalosis.

There has been a lot of discussion among patients on discussion groups about the high metal ion issue and pseudotumors. I am not a doctor or medically trained. I am a Patient Advocate, Hip Resurfacing Patient and Mechanical Engineer. I had the opportunity to attend the Second Annual U.S. Comprehensive Course on Total Hip Resurfacing Arthroplasty October 24–25, 2008 Los Angeles, CA. I listened to discussions about the metal ion issues and pseudotumors. I am going to explain what I learned in simple, non-medical terms since that is all I can do.
As an observer, I learned that the high metal ion issue has occurred in a small number of cases as a post op problem after a hip resurfacing. One of the most likely reasons, according to the experienced surgeons and presenters at the course, was the incorrect placement of the acetabular cup which resulted in additional wear on the bearing surface between the acetabular cup and the femur cap component. The hip resurfacing device is really a metal bearing made of High Carbon Cobalt-Chromium alloys. A bearing is designed to equally spread out the load over the load bearing components. If the components are not aligned properly, then only part of the bearing is loaded resulting in much more wear in that area possibly causing a high metal ion level. It was also explained that women seem to have more problems with high metal ions than men. Perhaps, this is due to the fact that most women use smaller sized hip resurfacing devices which causes more loading on the bearing surfaces than the men's larger sized devices.

When there is an abnormally high metal ion release from misplaced components, it seems to cause the surrounding tissue and bone to react adversely. The surrounding tissue and bone tends to become abnormal. Some doctors call the tissue reaction pseudotumors, AVAL (aseptic lymphocyte dominated vasculitis associated lesion), & others call it metalosis. Whatever name given to the abnormal reaction, it is not good to have this happening around the hip device since it could become loose, pain could result and possibly more severe medical reactions could happen. 
[From connie: While the idea of the occurrence of a pseudotumor or AVAL or whatever you want to call the adverse reaction, the idea of the component installation causing the problem is questioned now.  I just read a study showing that it is likely a patient sensitivity issue to the metal not a badly placed implant.]













6 comments:

  1. Hi Connie,

    My husband had his hip revision 3 weeks ago. Prior to the revision, he had the MOM Depuy pinnacle system and his cobalt was 140ppb 3 months before the surgery. What the OS found when he went is was a mess! He said there was boat loads of metal debris everywhere. It was determined that the metal shavings were coming from the cup and the interlocking metal liner. The metal liner was rubbing up against the inside back of the cup. The metal debris from the cup worked its way up around the outside back of the cup and the metal ion reaction created a palm size hole up in the pelvis behind the cup. His cup was hanging on with just a small amount of bone that had not been eaten away. The OS had a to do a major bone graft and put in a larger cup since there was not much bone left to press fit and secure it to. He had to put 2 metal screws to hold it. My husband was put on non weight bearing for 6 weeks in hopes that graft will heal and give him some stability in the socket. His surgeon did not see any wear or scratches on the ball that would warrant impingement with the cup placed incorrectly or the metal shavings were coming from the metal ball rubbing against the cup's metal liner. Nor was there any wear or corrosion on the stem.

    As such, in my husbands case, it was total product failure of the interlocking metal liner and cup system. It was not just simply metal sensitivity. No ones body should be subjected to deal with that much metal shards leaching off of device components into their muscles, bones, organs,and blood stream. He only had it implanted for 6 years. His surgeon called it metalosis and said he moped up as much as he could see but says my husband will always have metal debris in his body. What the residual affects this will cause has yet to be seen. The surgeon put in another Depuy metal ball to fit on the existing summit stem that was well fixed,. but went with a Biomet cup and poly liner. So glad he made the right choice and did not replace with another pinnacle cup. I personally think it has design flaws. His surgeon said my husband is not allergic to the cobalt/chromium ball or cup, but if they start breaking off metal particles into the body, over time the debris continues to accumulate and that is what the immune system cannot deal with and results in damage and metalosis.

    I too am interested in what sort of post op tests can be run to make sure the metal debris is not affecting some other area(s) of his body, i.e. liver, kidneys, heart, lungs, thyroid, brain, etc. You would think there could be some dye test or something like that which could pin point all the areas the metal debris has settled into.

    I am wishing you all the best with the tumors recently found on your scan. Please keep us posted as to what you find as the cause of them.

    ~Michele

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  2. Hi Michelle,

    Gee, I feel as though I am reading my own case with your husband's situation. I too had a large hole in the bone and required a bone graft. It has now been almost 3 months and I still am using a cane.

    There are plenty of tests called immunohistochemical tests but until I can get a pathologist to confirm a testing paradigm, I can't comment.

    I have published quite a bit on the FISH testing (floresent in situe hybridization) which looks at the gnetics as well but those tests aren't readily available to most physcians.

    Once I can get some tests ordered and we find out what they can or can't do, then I will publish something.

    sounds like you are quite informed and inquisitive which is what you have to be in dealing with this issue.

    I wish you and your husband luck in the new revision.

    Regards,
    Connie

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  3. Thanks Connie. I really appreciate all your research as I have learned quite a bit reading through your blog. :)

    I read your story prior to my husband's revision and thought of you when we were told about the bone graft. Were you also put on non weight bearing for 6 weeks? My husband is counting down the days (3 more weeks from today) before he can put weight on it and just walk! Sounds like it may not progress that fast. :( His recover has definitely be SLOW... compared to his previous 2 THRs.

    Are you still in pain? How does the hip feel when walking? Is the cane just for support since the leg is not strong enough yet?

    Interested to hear your stages in the recovery process since my husband may be facing the same.

    Best,
    ~Michele

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  4. HI Michele,

    I was not put on a non weight bearing plan. Quite the opposite of your husband's plan. I was in physical therapy, up on my feet and encouraged to walk the day following the surgery (however poorly it went...and it was poor at best.) I have noticed that every hospital has a different philospophy about this walking thing. I went through at least 30 PT sessions in the hospital, in rehab and post release. I think they really helped. They forced me to do things which were uncomfortable but necessary for recovery. I would not have known what to do on my own.

    In the hopital and rehab, the sessions were all weight bearing 2x per day regardless of the revision. I saw people in those sessions who had two knees replaced at once and they were on exactly the same regimen. All were on heavy pain meds of course. Their phlosophy was weight encourages more rapid healing. Who knows? I will look in the journals to see if there are any studies either supporting or denying this philosophy.

    My walking has improved greately. that is to say, I can walk without a limp but do have trouble getting out of a chair and the first 5 or 6 steps following are difficult which is why I still carry my cane. Walking after sitting for any prolonged period of time is still problematic after 3 months.

    One thing I did notice is that the strong leg gets very painful during the recovery due to it taking up a lot of the work and weight. I was on the walker for about 6 weeks to keep that right leg (non operated leg) from getting any worse. My good leg seems to be healing as well in that the pain is almost gone as my op leg picks up more of the burden.

    I see my orth surgeon in 2 weeks.

    Yes, I do agree, the revisions are much more difficult to recover from.

    I am sure your husband will do just fine as he has been through this before. It all gets better with time. the road to recovery is long but be thankful you got that hip revised!

    If you haven't gotten a script for PT, that I would surely recommend. While uncomfortable at first, it helped the most with my recovery.

    Lots of luck and let me know how your husband is doing.

    Connie

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  5. I have a pseudo tumour with a Metal on Poly THR. the surgeon commented that there was corrosion around the stem. He also insists that the problem is because my body reacted to the components. i.e - like it's my fault. I have mentioned that my hip has a sideways tilt (due to slight scoliosis left) and this could have caused wearing in the joint (i also spent a lot of time on a recumbent bike which could have exacerbated this situation. The surgeon insisted that the joint was properly aligned. i believe he misunderstood what I was trying to tell him. My guess is that pseudo tumours are a reaction to the particulates of wear (or corrosion) and that surgeons need to consider a larger skeletal picture when installing a THR (not just the upper femur and acetabulum). MY problem now is what to I do about the pseudo tumour - it was removed once and then re-appeared a year later. These things are not a good thing to have growing in your body. ..... JS - British Columbia (surgery at Vancouver General)

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    Replies
    1. Hello Jim,

      I have never heard of removing a pseudo tumor surgically....Generally, they go away once you have addressed the underlying levels of Cr and Co.

      It is likely that your body did react to the components. I would go see an expert in the hip metals. The best expert in the world is Joshua Jacobs MD who is the chief of Orthopedic surgery at Rush Presby in Chicago. he doesn't do phone consults. You would have to make an appointment to see him and have him review your scans and records.

      I am not a doctor so I can't help you but if anyone can, Dr Jacobs would be your very best bet.

      Hope that helps.

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