Tuesday, March 27, 2012

A counter point to the recent metal on metal warnings for large diameter hips>: Do they result in low or high revision rates? Should they be used or shouldn't they?

I am printing this journal article because it seems to be completely leaning in the opposite direction of the British medical advise which is to stay away from the large diameter hips.  It was curious until I looked at the authors.  I noticed this fellow Dr. Kindsfeter.  I knew I had seen his name previously.  Turns out that he did a study on these hips which Depuy printed in all of their sales literature re the safety of these large MoM hips:

Kindsfater K, Barrett WP, Dowd JE, Southworth CB and Cassell MJ. "99.9% Midterm Survival of the Pinnacle Multi-Liner Acetabular Cup in a Prospective Multi-Center Study." Poster Presentation #P077, AAOS, San Diego, CA. February 14-18, 2007.

Notice this reference  was to the  Depuy Pinnacle multi-liner acetabular cup. Unfortunately, no one can produce this study as it was just a poster at the American Orthopedic Association conference in 2007.  I presume it was NOT peer reviewed?

"Pinnacle Hip Solutions were designed to help provide a more fluid range of natural motion. DePuy Orthopaedics remains the leader in metal-on-metal technology, offering several advantages, including larger diameter bearings that can improve hip range of motion and stability. In fact, one study conducted since the device was approved in 2002 observed that an estimated 99.9 percent* of Pinnacle Hip components remain in use. Only Pinnacle Hip Solutions feature TrueGlide™ technology, allowing the body to create a thin film of lubrication between surfaces. The result is a smooth, more fluid range of natural motion."

Gee, its interesting because multi district litigation has begun with the Pinnacle metal on metal hip.  While they haven't been recalled, the law suits are piling up.

I just don't know what to make of this study in light of what seems to be some very strong ties with Depuy.  I don't know for sure of course but do you know of any other medical professional publishing new data on the great performance of metal on metal hips?  Well, here is one!  This would have had to be peer reviewed to get into this journal.  If I find other studies promoting the use of these hips, I will let you know.

Also note the dates of both sides of this argument:

The Kindsfeter article appeared before print on `14 March 2012
The British Lancet article appeared before print on 12 March 2012.

Is this just a mere coincidence?

Kindsfeter's compiled findings of other studies are quite positive vs the Lancet findings which are completely negative.

J Arthroplasty. 2012 Mar 14. [Epub ahead of print]

Large-Diameter Modular Metal-on-Metal Total Hip Arthroplasty: Incidence of Revision for Adverse Reaction to Metallic Debris.


Valley Orthopedic Associates, Proliance Surgeons, Joint Center at Valley Medical Center, Renton, Washington.


Large-diameter modular metal-on-metal (MOM) total hip arthroplasty (THA) may offer reduction in wear debris and improved stability. Four studies are summarized here that used a large-diameter modular MOM system. A total of 1076 THAs were performed. This article presents data from 779 of these THAs with minimum 2-year follow-up (mean, 4.2 years) or revision since index THA (21 hips, with 1 more pending). Overall survivorship at 2 years was 98.6%; at 5 years, it was 97.0%. Seven revisions for an adverse reaction to metallic debris (ARMED), and 1 additional pending revision for ARMED, showed marked variability in presenting symptoms and intraoperative and postoperative findings. Data show good clinical performance of the modular MOM system, but suggest that surgeons must be diligent in monitoring MOM THA patients and aggressive in diagnosing and revising patients with a potential ARMED


How do we reconcile these studies with the new recommendations comming out from the British folks recently?  Fodder for the lawyers?  see the following posts:

At last week's British Hip Society Annual Conference, in Manchester England: "... large diameter MoM primary hip replacements should no longer be performed.... http://www.mydepuyhiprecall.com/2012/03/at-last-weeks-british-hip-society.html

Recent Data from the Hip registries in England and Wales: Metal-on-metal stemmed articulations give poor implant survival compared with other options and should not be implanted


Lancet. 2012 Mar 12. [Epub ahead of print]

Failure rates of stemmed metal-on-metal hip replacements: analysis of data from the National Joint Registry of England and Wales.


  1. Don't be fooled! This article is all about the $$ paid from Depuy to Kindsfeter as well as the other consultants and product designer who are listed as it's authors. Verify for yourself on Depuy's website.

    I sure would lean towards any countries hip registry and recommendations over what is being disclosed in the US.

    Just read The Harbinger, by Jonathan Cahn. What an insightful book! Puts all this MOM going ons in perspective. America needs to wake up and see its glory days are numbered if we don't turn back to what this country was founded on.

  2. Thanks for the note. See my post today:

  3. I'm currently one month shy of my 1 yr anniversary, of my Pinnacle implant. Since about 3weeks post-op, I had nothing but probs; 3 PT's, Total of 3 MDs, two whom are specialists, now I finally received my request for Cobalt/Chromium levels to be drawn, & have an appointment to discuss a date to have it taken out. I have several Symptoms related to this implant & can't wait to have it removed. For me..... the failure rate is greater than 100%, because of the time from onset of symptoms. I've seen both International as well as Domestic studies...... the article in question, is just a $$ ploy. Doesn't mean a thing!!!!