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This, That, and The Other

Discussion in 'Hip Replacement Pre-Op Area' started by Bumblebee, Feb 7, 2018.

  1. Bumblebee

    Bumblebee senior
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    Hi @Josephine , I was wondering if you can weigh in on the pros and cons of smaller vs larger femoral balls. My surgeon prefers the smaller ones with a thicker cup. Have you seen more risk of dislocations of the smaller ones? Any difference in hip range of motion with either choice? Any issues of impingement?
     
  2. Josephine

    Josephine FORUM ADMIN, DIRECTOR Administrator

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    An interesting question.

    Back in the days when Professor Sir John Charnley developed his hip joint, it had a 22mm ball with a thick plastic cup. His reasoning was that the wear would be less with a smaller bearing and the thicker cup would also prolong the life of the device. He was actually correct as a lot of his hips lasted years and years (67½ year old - the THRs, not the patient!)

    However, people began to redesigned over the years and decided that a larger head would reduce the incidence of dislocation. This appeared to be a solution even though the Charnley hip was't demonstrating great statistics for dislocation anyway. But many years after this, the metal on metal hips started giving problems and after a few years, it was realised that this issue was a serious one and metal on metal hips were take off the market. However, it was also discovered that the over-large head as used by most of the MoM hips (the infamous ASR hip being one) didn't work too well with the remaining bearing types which were metal on plastic, metal on ceramic or ceramic on ceramic. So the head sizes are now pretty much 28-32mm.

    There are still a lot of surgeons using the original or updated versions of the Charnley or the Oxford which has also been around for decades. My advice is to go with what your surgeon prefers. He knows what he is doing and that's what you are paying him the big bucks for!
     
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  3. Bumblebee

    Bumblebee senior
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    Why did I know you would say that last comment?:heehee:
    @Josephine ....is the range of motion just as good with the smaller one?
     
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  4. Josephine

    Josephine FORUM ADMIN, DIRECTOR Administrator

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    Oh yes! For sure
     
  5. alexthecat

    alexthecat MODERATOR Moderator

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    I have a 32-mm ball in my THR and I'm quite happy with it. I think you will be too. Not that I have anything to compare it to but the natural hip I have on the other side.

    Sent from my Venue 7 3730 using Tapatalk
     
  6. dapplega

    dapplega junior member

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    Interesting topic...
    My implant is dual mobility so it has a 28mm ceramic head but the poly head/cup is 50mm (so 11mm of thickness around). I understand the thinking to be that the dual articulation allows a greater range of motion while decreasing dislocation. However, with 2 articulating surfaces (one being ceramic on poly and the other the poly on metal of the acetabular cup) there may be a drawback of slightly more wear (not confirmed just my surmising...). I'm curious what the average thickness is for traditional poly that is static in the cup?
     
  7. Bumblebee

    Bumblebee senior
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    How is your range of motion with the 28mm?
     
  8. dapplega

    dapplega junior member

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    Dual.jpg
    @Bumblebee - my range of motion is better than it was prior. The claim is up to 165 degrees with lower dislocation risk... Tried to attach a pic of the concept but you can find it pretty easy with a Google search...
     
  9. sfbaylover

    sfbaylover junior member

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    @Bumblebee

    Great question, and one I am concerned about as well. I need a right hip replacement, and have been hemming and hawing with regards to actually scheduling the surgery (I have scheduled, cancelled, and rescheduled a few times already). I am 43 and have had hip issues since age 13. Anyways, one of my concerns about having a THR is that it will limit me mobility wise or not enable me to be as mobile or athletic as I would like to be. Obviously, I want my replaced hip to be as stable as possible. I know many surgeons favor a large femoral head in the hopes that it will create a more stabile hip joint; other surgeons seem to prefer a smaller femoral head, one that will be big enough to provide adequate stability while still providing adequate bearing thickness (which means a longer lasting hip).

    One surgeon said that he would likely use a 36mm ceramic ball for me. This was a surgeon from HSS in New York City, who has been doing hip replacement for over 40 years. Another local surgeon said he would likely use a 32 or 34mm ceramic ball (along with an anterior approach; first surgeon does mini-posterior approach). This second surgeon actually trained under the first surgeon at HSS during his fellowship. Both guys obviously are very experienced and know what they are doing, so it's a case of trusting the wisdom and judgement of either guy.

    Obviously, 36mm sounds like the better choice to me (at least superficially), due to the supposed greater stability and range of motion offered by a larger femoral head, but maybe the 32 or 34mm would be just as effective (and quite possibly afford a longer lasting implant).

    So many things to consider prior to surgery.
     
  10. MammaT

    MammaT supremo

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    Lol-I never gave thought to any of this. Of course , at 63 I want to be able walk and play with grandkids. You are all so much more thorough than I! I just trusted surgeon to put in a joint that will do the job. I’ll have to ask about sizes at follow up visit.
     
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  11. Layla

    Layla FORUM ADVISOR Forum Advisor

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    Hi @sfbaylover
    Hmm, since I can't have a do over and hopefully never need one :praying:
    I'm going to ignore all this size talk since I wasn't wise enough to consider it going in :doh:
    You mean we actually had a say in all this :what: @dapplega
    Say it isn't so happy, sunny @Bumblebee
     
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  12. dapplega

    dapplega junior member

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    Ha! @Layla nope... I went with what the surgeon wanted... :)
     
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  13. Josephine

    Josephine FORUM ADMIN, DIRECTOR Administrator

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    Quite so!
    In point of fact, there is no difference between them except a mm or two of metal! They are all sound and have really good stats, stability and longevity according to the National Joint Registry (UK). What matters most is the skill of the surgeon and nothing more. The rest is just semantics!
     
  14. Bumblebee

    Bumblebee senior
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    Well, a girl can ask, can't she?:wink: Curious minds want to know.
     
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  15. Layla

    Layla FORUM ADVISOR Forum Advisor

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    Love that happy, smiling @Bumblebee and all the good cheer you spread here.
    I didn't think to ask, I blindly trusted :hissy: Numbskull, lol!
     
  16. newhip126

    newhip126 member

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    Wow, you all are amazing. I never thought to consider ball/socket size. I liked what @Josephine said about that’s why we’re paying surgeons the big bucks. Lol. I usually research, ask a million questions but for hip surgery I basically gave myself over to the surgeon, trusting he knew best. I am now glad I didn’t worry about all this, and have no worries about next hip. I’m usually an over thinker but haven’t for all this. Good to know tho. Great discussion.
     
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  17. anny

    anny graduate

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    Interesting discussion, not one I'd thought about before......so are we saying bigger is better? or good things come in small packages? aagh my head hurts just thinking about it.....don't think I'll be reaching for Dr Google on this! Besides, think my surgeon would give me a very old-fashioned look if I tried to suggest what he uses.....only get 10 min consult so would be a very short conversation :whistle:
     
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  18. Bumblebee

    Bumblebee senior
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    @Josephine ...does using a thicker liner and smaller ball lengthen the leg? And how do they shorten or lengthen a leg?
     
  19. Josephine

    Josephine FORUM ADMIN, DIRECTOR Administrator

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    Neither.
    No it won't because there are other factors that govern it such as the length of the neck of the stem or the degree the stem is implanted into the femur.
     
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  20. Horseshoe

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    @Bumblebee , interesting discussion, I researched ball/head size and implant types too :snork: . However, things changed during actual surgery and received a different head type on the right, metal instead of the requested ceramic, due to a sizing issue to even out leg length. Both sides are 36mm and so far, so good. Have not really pushed ROM yet.

    As I understand it, offset (neck length) affects leg length and can be tweaked. Both my legs are a tad longer after thrs and new hips stick out a bit more at the sides, greater trochanter area, IT band is sensitive. OS said they try to maintain natural patient offset but it's sometimes increased for stability. Legs are even so no complaints but it's like getting a new body below the waist, good but different :)
     
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    Last edited: Feb 10, 2018

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