For over four years I have been investigating problems associated with Stryker Accolade TMZF Titanium hip stems. Of course the Rejuvenate and ABG II failures and subsequent recall are well-known and much written about. But, during our investigation into the Rejuvenate and ABG II TMZF failures, we started seeing a common theme develop with other Stryker hip stems that were also made of TMZF Titanium.
What Our Stryker Accolade Investigation Revealed
Our investigation revealed that Stryker’s product mix included three other stems that were made of TMZF. By far the most commonly implanted TMZF monoblock stem was the Accolade. As more and more Stryker Accolade failure clients poured into our office we became convinced that the Stryker Accolade was as big a problem as the Rejuvenate or ABG II. The exact same combination of mixed metals exists when a Stryker L-Fit V40 Chrome/Cobalt head is placed on a Stryker Accolade stem. Patients who had Accolade failures presented to their doctors with almost identical complaints to Rejuvenate patients. Both experienced pain and restricted motion. When their surgeons were smart enough to order the appropriate blood tests, testing frequently revealed metal poisoning and imaging studies showed large fluid collections along with pseudotumors.
As time passed, a couple of articles appeared in the medical literature indicating that Accolade stems married to L-Fit V40 chrome/cobalt heads were failing due to fretting and corrosion at the head/stem connection. However, the early medical journal papers suggested that this occurred only with larger heads. In our own experience, we saw more failures with larger heads but, we also had plenty of failures with smaller heads. Typically, “large” heads are considered to be 36mm and larger.
What’s the Difference Between a Recalled L-Fit V40 Head and a Non-Recalled L-Fit V40 Head?
With that background, Stryker’s recent recall of 44,000 L-Fit V40 metal heads became a real head-scratcher for two reasons. First, the recall only involves heads that were manufactured over a nine year period from 2002 through 2011. Our experience indicates that heads implanted before and after 2011 fail just as often. There was no regulatory activity indicating that Stryker magically redesigned the V40 heads in 2011. So, why was an L-Fit V40 head manufactured in 2010 subject to recall but one manufactured in 2012 not?
Second, the recall only includes heads 36mm and larger and with offsets of +4 and greater. Although I disagree, I can see the strategy behind the 36mm size but, the offset issue was puzzling. Offset is simply a fancy word for where the head comes to final rest on the stem. By altering the interior taper of the head, it will either sit further out or closer in on the stem. Zero offset would essentially be neutral. If a head has a negative offset, it sits further down on the stem. Plus offsets move the head further out on the stem. So, a +4 head would sit further out on the stem than a 0 offset. +8 would sit even further from the stem than a +4 and so on.
Our experience indicated that all of these heads fail, not just the extreme offsets. Just last week I reviewed a new case in which a lady had a catastrophic failure including extensive bone and soft tissue damage from a Stryker Accolade TMZF stem with a 28 mm. L-Fit V40 head. So, back to the question of Stryker’s recall being limited to 36mm and greater, +4 offset and greater, pre-2011 heads?
My Conclusion
Allow me to take a stab at this one. Knowing absolutely nothing changed in terms of head design in 2011, why all of a sudden were these large heads with big offsets magically okay after 2011? Well one huge thing changed in 2011/2012. Stryker eliminated TMZF titanium from its entire product line. Rejuvenate and ABG II were recalled. The Stryker Accolade was redesigned in 2011 to eliminate TMZF and convert the implant to Ti6 titanium. So, after 2011/2012 Stryker had completely eliminated TMZF from its product line. In our view, this is as much a belated TMZF recall as it is a large head, big offset recall.
