surfacehippy] Report from the American Academy of Orthopaedi c Surgeons ...

[Guest guest]

There are Cracks in the Walls of the Establishment! The pendulum is indeed

swinging. An awesome and most encourging posting. Thank You!

Rob K. (NYC) r/BHR De Smet Feb 3rd, 04

>

> Report from the American Academy of Orthopaedic

> Surgeons (LONG)

>

>

> Hello All--

> I attended this symposium at the AAOS meeting in San Francisco.

> Two of the presenters perform hip resurfacing surgeries in the US,

> and I was curious to see what sort of reception they'd receive.

> I'm not an orthopedic surgeon or an M.D. of any sort. I'm not an

> engineer, either, but I am a scientist accustomed to attending

> large conferences broadly similar to this one. I can't claim any

> professional expertise on the topics presented in the symposium.

> With this in mind, my notes and comments on the presentations are

> listed below.

>

>

> 2004 Meeting - American Academy of Orthopaedic Surgeons

>

> Wed 10 March, 8:00-10:00

> Hip Arthritis in the Young, Active Patient: Surgical Options

>

> J.C. McCarthy - Arthroscopy for labral tears

> R.T. Trousdale - Debridement (?)

> R.F. Santore - Osteotomy

> M.A. Mont - Resurfacing

> T.P. Schmalzried - THA: crosslinked polyethylene

> W.J. Hozack - THA: ceramic

> L.D. Dorr - THA: metal-on-metal (MOM)

>

>

> Of most interest to our group, of course, is Dr. Mont's presentation,

> and also the pros &cons of MOM ( " the metal ion issue " ).

>

> Dr. Trousdale said something interesting during his talk:

>

> " Most young patients who have THA a structural disorder;

> primary OA is very rare. "

>

> The first 2 American docs I saw were not able to give me a straight

> answer about whether the OA was a " genetic propensity, " a structural

> defect in the hip joint, or caused/exacerbated by running. The OS at

> UCSF told me I had a " genetic defect " because I am of Northern European

>

> descent, which puts me in a higher-risk category. Whatever.

> It's probably structural instead, which is better when considering

> the possibility of early-onset OA in other joints.

>

> OK, now on to resurfacing. Mont talked about 2 procedures:

> (1) hemi-resurf for osteonecrosis, when the acetabular cartilage

> is intact;

> (2) total resurf for arthritis.

>

> The reputation of resurfacing in general is tainted by old results!!

> The old metal-on-thin-poly implants did have a high failure rate.

>

> HEMI - " do the least procedure that does not burn bridges "

> This is a time-buying procedure, allows high activity levels, but

> many patients report more groin pain.

>

> TOTAL - ~20 sites in the US, 2 devices, 2000 patients

> In contrast to the US, about 40% of OA patients in Australia

> get resurfacing instead of total hip replacement.

>

> Mont uses the anterior-lateral approach. He said the surgery is

> technically difficult, not something a surgeon can pick up overnight.

> He emphasized the importance of skill and experience.

>

> Amstutz/JRI results - 400 patients (600 now), mean age 48,

> 95% survivorship at 4 years (most failures were from the earliest

> series)

>

> High activity levels in resurfed patients, including marathon running.

> Great ROM (range of motion). A measure of " hip abduction moment "

> showed that gait is better with MOM resurf than traditional THR.

>

>

> METAL vs. CERAMIC BEARING SURFACES

>

> Dr. Schmaltzried spoke about crosslinked polyethylene. His talk

> was heavily weighted towards materials science, and I cannot say

> anything useful about it.

>

> Dr. Hozack ( " Mr. Ceramic " ) took a crack at the MOM ion issue in

> a slide showing the Iraqi (dys)Information Minister, saying,

> " there's no problem with metal ions. " Of course, he believes there

> is a problem with metal ions, but didn't present any convincing data.

> He touted ceramic THA, with a pretty low fracture rate BUT some

> problems with impingement. What was characterized as " stripe wear "

> improves if a larger head is used. For patients younger than 50,

> he recommends total hip replacement using ceramic parts.

>

> Dr. Dorr ( " Mr. MOM " ) asserted that ions are a scare tactic!!

> He said that there have been absolutely no complications, not a

> single report of cancer, in 40 years. No hypersensitivity, no

> reports of increased pain. He noted design improvements, use of

> cobalt-chrome metal, he discussed clearance rates.

> He mentioned a series of ~100 hips, 5-11 yrs out, 96% intact.

> Success stories at 12 yrs post, 90% survivorship at 25 yrs!!,

> 95% patient satisfaction. This bodes well for the revision patients.

> The large head, MOM total hip seems like what we should opt for

> should any of us need a revision of our resurf, as others have

> mentioned on this site.

>

>

> QUESTION &ANSWER PERIOD (directed to Mont, mostly, but some to Dorr)

> This is what I was waiting for: anti-resurf hostility would

> show itself now.

>

> Q - would you use MOM in women of childbearing age?

> A - yes

>

> Q - do ions cross the blood-brain barrier of the fetus?

> [this could potentially have an effect on the developing brain]

> A - don't know (Mont); but someone else seemed to suggest no,

> they don't (?)

>

> Q - at which stage of AVN do you still do resurf?

> A - don't wait too long! within 6 months of onset

>

> Q - the enthusiasm for resurfacing is puzzling, Dr. Mont.

> What about Amstutz' failure rate?

> A - failures were in the 1st group of 100 [here I believe he's

> talking about the most recent results]

> - can get 99% survivorship at 5 years! not so sure at 10 yrs, though.

> [resurfacing will not " catch on " in the US until the 10 yr data are

> published, is one going opinion]

> - Mont urges caution and a good learning program.

>

> Q - Is the fracture rate higher in total than hemi-resurf?

> A - [i didn't understand his answer]

>

> Q - Sounds like deja vu from the late 1970's - " learning curve " ,

> expecting a high failure rate at 7-8 yrs.

> [this guy was very hostile, and put words into Mont's mouth;

> Mont was just saying that the 10 yr results aren't in yet, so we

> need to proceed with caution, NOT that a spate of failures are

> expected in 2 yrs. This was actually a commentary, not a question]

>

> Rebuttal Comment from the next audience member - an English doc

> who did 300 resurfs himself; he mentioned his multi-center study

> shows a very low fracture rate. Intermediate-term results are

> excellent. He found the debate rather curious.

> [i think this was someone from the Corin trial in the UK, reporting

> on the Cormet Resurfacing Hip at a Scientific Exhibitor booth. I

> have the abstract for this, but did not try to get into the Scientific

> Exhibit area.]

>

>