AAOS Conference Hip Society Meeting

General Overview By Vicky Marlow

March 8, 2008

There was a lot of discussion about placement of the cup position.

Cup position with large open angles will cause more metal debris. It was agreed that in the past the doctors were more concerned about the placement of the femoral component but they are finding out that patients are having more long term problems with ROM (Range of Motion) or lack of ROM if the cup placement is off. The cup position is crucial to avoid impingement; they need to watch the anteversion and the orientation of the lip. The doctors should also take care to remove any osteophytes.

On a side note, this is an old email I received from Dr. Bose when I was still doing my research. At that time I was reading so many posts from patients experiencing groin pain so I asked Dr. Bose about it. When he sent me this email, I was still pre-surgery. Apparently the problem continues today since I still read many posts from patients experiencing groin pain. It looks like the majority of doctors are now finally beginning to recognize this as a possible problem caused by placement of the cup, but as you can see Dr. Bose knew this back in 2005.

From: Vijay C.Bose
Sent: Monday, October 17, 2005 6:53 PM
Subject: Re: Post Op PT


Yes, psoas tendinitis is an important reason for groin pain in resurfacing surgery.

This is peculiar to resurfacing as the cup for resurfacing is a very large profile i.e. half a sphere. Nearly all THR cups are only portions (arc) of a hemisphere.

Hence if the antero-posterior orientation i.e., version of the cup is marginally off the ideal, it would not be a problem with THR. However in resurfacing, due to the very large profile, if the version is less than ideal the ant edge of the cup will protrude out of the bony front wall of the acetabulum. The psoas tendon will rub on this and patients will typically complain of pain when attempting to lift their leg in a standing position.

For this reason we now take extra care to get the version right and most resurfacing surgeons leave a 3mm rim of osteophytes over the ant edge as a safety precaution to avoid this problem.
with best regards
vijay bose

As far as selecting the ideal candidate it was brought up that gender should make no difference in selecting a patient for resurfacing, what really matters is the width of the patients’ femoral neck.

There was still a lot of talk about computer navigation and many doctors are very skeptical about that. The experienced surgeons still find more accurate placement without the use of computer navigation.

McMinn was in a debate with another surgeon on THR vs. Hip Resurfacing. He said that he wanted to let the entire ortho community know that he was not completely against THR’s. He then showed a slide of a 97 year old woman that he had performed a THR on. He got quite a laugh from the audience of over a thousand orthopedic surgeons. McMinn really has quite the sense of humor.

He also stated that there is really no difference between the two procedures as far as operating time or blood loss. (Vicky- Of course mileage may vary depending on the experience of the doctor)

McMinn felt the learning curve for doctors was 150 hip resurfacings. He also felt that doctors that do a low volume (majority in the U.S.) of hip surgeries per year should not be attempting to do resurfacing. Only the large volume hip doctors should do resurfacing.

McMinn’s take on some other devices were:
His prior experience with the Cormet 2000, also known as the Corin or Strykers’ device and the double heat treatment they started to do in 1996. You can learn more about it on his site rather than repeat what he stated by clicking here and going to Lectures – “10 Year Survival of Double Heat Treated Hip Resurfacing from 1996”

Click to visit the McMinn Center website.

On the Zimmer Durom he said it had a 7% revision rate in the first year and felt that it was not as good of a device due to the device having a sharper lip and higher titanium level.

He then mentioned that as far as the ASR goes, he could not possibly begin to cover all of the problems with it and left it at that. You can read more about his opinion on the link above to McMinn’s site under Lectures – Northern Lights Debate.

A really interesting part of the whole meeting was a statement made about return to activities after hip resurfacing.

It was stated that doctors will tell their patients what the restrictions are, and they are finding out more and more that the patients are not listening to the restrictions and just going out and doing what they want to anyway.

With the growing number of younger active patients getting hip resurfacing, they are seeing things they never would have imagined someone doing after hip surgery before. Doctors are learning that the patients are the one’s now teaching the doctors exactly what a well placed hip resurfacing is capable of doing.

Vicky - Interesting concept, patients educating doctors on what is possible with resurfacing. Thanks to all of the Dru Dixon’s (first surface hippy to compete and finish an Ironman after BHR surgery), Steve Cohan’s (finishing his first Ironman post hip resurfacing), Mark Baer’s (skiing just under 4 weeks post op) Scott Tinley’s (surfing full out at six weeks post op) and Joan Gunnes (teaching yoga at 13 days post op) of the world.

Look under the Stories section of all the athletes that have had their hips resurfaced as well as the surface hippy youtube page.

Click to see Surface Hippy Info on YouTube.

And that wraps up my overview of the AAOS conference.