Talk to Dr Steve
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Saturday, July 14, 2012
I am an accidental authority on metal-metal complications. I observed my first hip replacement in 1979, started assisting on the procedure in 1982, and performed my first as primary surgeon in about 1985.
I started practice in Alaska in 1992. I was the first up here that had interest in revising failed hips. That interest drove a collaboration with Dartmouth Biomedical Engineering Center (DBEC). DBEC analyses hip explants, I have sent them about a hundred over the years (including my own). They are likely as independent of industry as any academic lab that does this work. They are best known for work that was seminal to the improvements in the polyethylene use in the “Gold Standard” metal-on-plastic and ceramic-on-plastic hips. This work will likely be eclipsed by their evolving analysis of the mechanisms of failure of metal-metal hips.
I have been captured by why hips fail since training. My first publication was about femoral fractures around hip replacements (periprosthetic fractures), this was my training research topic. It won the big prize at a regional US orthopedic meeting in 1992 and saw print about then in CORR.
Early in my Alaskan hip revision experience I stumbled over four catastrophic failures of thin XLPE acetabular liners of one design (Zimmer, Longevity, Trilogy). The analysis of those liners by DBEC lead to a podium presentation at the Annual AAOS meeting in 2006 and publication later that year in JBJS-American. Ironically, this experience lead to my selection of the ASR XL as my primary THA several months later. This JBJS paper likely influenced the redesign of the implant systems that use XPLE and relatively large femoral heads (32 mm and greater). This technology, either as Metal-on-Plastic or Ceramic-on-Plastic (CoP) is what I exclusively use now in both primary and revision hip replacement.
I will not dwell here on my own ASR XL experience as it is well described in my JBJS-American (December 2010) publication that you have a link to on your site. I was the index case and the author of this paper that found that and approximate million metal-metal hip implantees are at risk for cobaltism (systemic cobalt poisoning). The collaboration of DBEC was critical to this work.
Once I realized at the end of 2009 that I had been poisoned by my ASR it was clear that many others might be baffling their surgeons and primary medical providers with a litany of unexplained mental, neurologic, cardiovascular, and thyroid maladies that might be falsely attributed to normal aging or just madness.
This realization stimulated a collaboration with the Alaska State Epidemiologist (Dr. Joseph McLaughlin) that resulted in a May 2010 publication in the Alaska State Epidemiology Bulletin, “Arthroprosthetic Cobaltism (APC) in two Alaskan men.” The June 2010 edition of “Alaska Medicine” featured a paper on the description and diagnosis of Arthroprosthetic Cobaltism (APC) that predated my JBJS publication by 6 months.
The Ak Epi BULL attracted the attention of CDC Atlanta that wished to summarize it for their Weekly Morbidity and Mortality Report. This was nixed by the FDA because a turf issue. The WMMR has national circulation, publication there the summer of 2010 might have saved thousands the grief of metal-metal implantation and tens of thousands the delay in the diagnosis of a progressive multi-organ-system illness.
I was surprised by the FDA’s response. I was naive, I believed the primary mission of the FDA was to protect the public. I started a campaign to educated the FDA about the perils of metal-metal.
At a certain point I was curtly dismissed by the physician in charge of the FDA investigation, “Dr. Tower you do not understand, when the FDA thinks their may be a problem with a device we gather representatives of industry to define the problem, you are not affiliated with industry, you have no standing with us.”
This occurred in the fall of 2010 just before my JBJS publication. Fortunately, to its credit, two years later the FDA is showing interest in metal-metal complications.
My ASR was implanted in March of 2006, within a year it was clear that something about the hip was not right. I had my first metal levels drawn.
My blood cobalt and chromium levels were about 200 times mean normal and 40 times the Biologic Exposure Index (BEI).
The BEI is used as a marker for industrial hygiene, levels below the BEI and thought not likely to be harmful. This peaked my curiosity.
I started to call DePuy design surgeons, distributors, and engineers. I was reassured not to be alarmed, they asserted that such levels were not known to be a problem. I also made inquires to my surgeon and other prominent American hip surgeon authorities on arthroprosthetic design and technique, same story, no worries. I was naive, I believed them, they were the authorities on the topic, they ought to know.
Water over the bridge, but seven years later I am still have difficulties in getting the topic addressed at the annual meeting of the American Academy of Orthopedic Surgeons. The officers of the Academy and the officials that control the Academy’s educational efforts have been closely tied to industry. I was allowed an editorial piece in the AAOS’s monthly newsletter a year ago, “Bad Bearings.” It was sadly prescient.
Frustrated in my efforts to educate surgeons, the FDA, and industry about the risks of the metal-metal hip technology I allowed an interview with Consumer Reports hoping to educate patients directly. Since then I have been contacted by patients from all corners of the world that believe that they might be in trouble. Many have a plausible story for Adverse Local Tissue Response (ALTR) or Arthroprosthetic Cobaltism (APC) but many of those concerned are not at risk (they do not have metal-metal hips).
Getting Dr Steve’s help:
In order for me to make sense of the case history of a concerned individual I need to know the following.
What is the brand and type of hip. This information can be acquired from the surgeon or the hospital, it is best to get the actual implant inventory. All hip components come with duplicate stickers that are placed in the hospital record, copies are often given to the surgeon for the clinic chart. If this is not available the critical factor is the materials of the opposing sides of the hip bearing. If the material mating with the head is plastic their is no risk of cobaltism a long as the hip was not a revision operation for a fractured ceramic socket or head.
If your hip is known to be a metal-metal (all “resurfacings” done over the past decade are metal-metal) the next most important information is a serum or whole blood cobalt level. Your GP can organize that if your surgeon is reluctant.
Your problems at the hip and any decline in mental or general health then needs to be known.The case reports of cobaltism to date suggest that serious mental or general health decline are unlikely if your serum cobalt level is less than 10 micrograms/Liter (mcg/L). Parts per Billion (ppb) are equivalent to mcg/L. If your report returns in nano-moles per liter (nm/Liter) a bit of math will be required to convert to mcg/L. Your metal levels is less helpful in excluding an ALTR problem. Some individuals react to minute levels of chrome-cobalt debris based on an immune mechanism. Several to the most severe cases of tissue destruction that I have seen at revision surgery were in patients with serum or whole blood cobalt levels of less than 1 mcg/L.
If you are concerned that you may have a metal-metal hip related problem contact Earl with the following information.
The brand, model, and bearing type of your hip.
The date of implantation.
Your serum or whole blood cobalt level.
Any problems that you might be having at the hip.
Any decline that you have experienced in your mental or general health since your hip replacement.
JPEG or DICOM copies of the x-rays of your hip. It is helpful to have those that were done after the operation and the most recent.
Earl will pass that information along to me I will help as best I can. It is important to realize that my advice will be general and should supplement but not supplant the recommendations of your treating physicians.
If your surgeon seems indifferent to your concerns you might be better served by involvement of your primary medical provider.
If you do require revision of your metal-metal hip request that your surgeon send the explants to DBEC for analysis. This is the path to understanding the metal-metal hip debacle and it is this understanding that will prevent future arthroprosthetic misadventures.
Denise asks about Stryker ABG 11 modular stem recall 22 August 21012
Have a question for Dr. Steve. What are your thoughts on the stryker ABG 11 modular stem recall and possible metal issues. I have this stem with a ceramic head and stryker dual mobility ADM cup. It seems to me stem is titanium, neck is co-cr and head is ceramic so not really a metal on metal problem. ADM has the ceramic head on poly shell, titanium cup. This stem was recalled with the rejuvanate which I bleiev has a metal ball which seems to be more of a problem. It seems to me the ABG was just bundled with the rejuvanate due to they are both modular. Thoughts on this? Can it be a problems. Your thought via email would be appreciated.
Dr Steve’s Reply – 25 August 2012
Styker (to my knowledge) never offered a metal-metal bearing hip other than marketing Corin’s resurfacing product in the US but their Rejuvatate stem is a problem with chrome-cobalt debris generated apparently at the modular connection between the stem body and the base of the femoral neck. At this junction the mated surfaces are both chrome-cobalt alloy. It is possible that similar debris might be generated at the modular head neck junction were the mated surfaces might be either chrome-cobalt on titanium or chrome-cobalt on ceramic. The potential problems at both junctions is likely increased if a larger head diameter is used, a longer neck is used, or if a “plus” head is used.
The mechanism by which metal debris is generated at these junctions can be both fretting (micro-motion) or galvanic corrosion. These problems are likely common stems of other brand that have stem/neck modularity (a handful of models and brands) or neck/head modularity with a head diameter of > 36 mm ( many ). Patients that have hips that generate this type of wear likely will not have the markedly high blood cobalt or chrome level that might result in outright systemic toxicity (cobaltism) manifest by damage to the mind (affective, memory, and learning problems ), hypothyroidism, or heart and vessel issues ( cardiomyopathy and hypertension ) but might have problem with tissue inflammation and tissue damage around the hip ( Adverse Reaction to Metallic Debris or ARMD).
ARMD reaction can be serious and might result in a difficult salvage situation for the patient that requires revision surgery and the surgeon that performs the revision. The major problem being the loss of ligaments, tendons, muscle, and bone. Many patients with severe loss of tissue will be condemned to a less than ideal result from their revision surgery with the most common problem being hip instability (dislocations). Most but not all patient with ARMD reactions will note pain and will have increased fluid or soft tissue masses about the hip – cystic (fluid) or solid psuedotumors -. These problem might not be apparent on plain X-ray but are usually found by ultrasound or metal suppression MRI, or CT exam.
Not all of the Rejuvanate stems had a modularity between the neck and the stem body, in the smaller sizes the stem body and the neck are one piece.
I am bothered by the Class Two recall designation. The product is silently removed from the market and surgeons that implanted the devices are notified by letter that there is a potential problem with the device that the surgeon should be aware of but it is not recommended that patients be notified and systematically brought in for review. I think many surgeons will be content to let sleeping dogs lie and not contact their patients and that some might have a smoldering problem in which the symptoms are not bad enough to cause them to contact their surgeon.
This type of recall seems to transfer the liability and responsibility from the manufactureur to the surgeon, to the determent of the patient. In my experience with this type of recall the representative of the company that made the implant is usually present at the time of revision surgery and will request that the explants be surrendered to him or her to be sent to the company’s lab for analysis. When this happens the surgeon and patient never see the explants again and if an inquiry is made as to the results of the “analysis” the answer is typically, “we could not find a problem with the device, the surgeon must have installed it wrong.”
I have been revising hips for twenty years and found and published on defects on implant designs (the combination of the Zimmer Trilogy acetabular shell with a thin cross-linked liner made of Longevity plastic). Though published this information never lead to a recall of any sort, this implant combination was quite common and likely hundreds of patients required revision because of failure of the liner (rim cracking). My paper may have contributed to the design of this product.
These flaws in implant design and the delayed nature of their discovery is being experienced now on a much larger scale with the resurfacing and modular bearing surface metal-metal hips. One system has been formally recalled (the Johnson and Johnson –DePuy – ASR), two others have had class 2 recalls, the Zimmer Durom (transient), and the modular Smith and Nephew metal-metal liners in their R-3 line.
It has been recommended by the British Orthopedic Association that surgeons stop implanting the modular metal-metal hips but most are still no the market. I think this is in essence a “silent recall” and is indicative of unbalanced industry influence on orthopedic professional organizations.
The FDA (US) and MHRA (UK) generally only accept input from orthopedic professional organizations, largely the same surgeons that are consultants to industry. For this reason I believe their response the complications of these devices is emblematic that these “regulatory agencies” are more protective of industry that of patients. This is not overt corruption, these agencies do not have the budgets to do independent pre or post market research. Almost all research on orthopedic devices is funded directly or indirectly by industry,
“He who takes the King’s coin whistles the King’s tune.
WOW! Glad to see this question/article. Had a rejuvenate put in on 11/29/2011 and was doing great until April 2012 when I started having some pain with walking and hip flexion. Went to see surgeon and he said xray looks fine just take it easy with the exercising. I am only 35. Things never got better only more pains and issues. Stumbled upon the recall while googling hip/thigh pain after 8 mos post op and went to see surgeon first of August only to be told I probably have muscle weakness and no reason for pain because xray looks good it was not from the rejuvenate at all. He agreed to do lab work at my request. Well, lab work came back this week and chromium was 0.5mcg and Cobalt was 3.9 mcg and he assured me that it was all normal even though it was a “little high”. I asked about an MRI and he told me it wouldn’t show anything because of the metal implant same thing with CT. He offered physical therapy for the “muscle weakness” and popping in my hip and do xrays every 6 months instead of every two years now and watch my levels every 6 months or so. He assured me that the rejuvenate was not my problem and my leveld were not “toxic” and no need to worry. I know that I was doing great right after the replacement and had no pain and now I am going backwards as far as recovery and he thinks the recall has made me “hypersensitive” to the pain. I had synovial chondromatosis for three years before being diagnosed and worked every single day, I am not being hypersensitive. Thanks for the great articles!
here is Dr Steve’s reply to the points you raised:
Christy ought to request a “Metal Suppression MRI” (MSMRI) and get her implant inventory from her surgeon or from the hospital to confirm that her Rejuvenate stem has a modular connection between the neck and stem body.
New and progressive groin pain with flexion of the hip is common in patient with Adverse Reactions to Medal Debris (ARMDs), this is because the tendon that flexes the hip runs directly over the joint such that increased fluid in the joint or inflammation of the tissues this tendon gets involved and that generates the pain.
I have seen patients with(ARMD) in patients with blood cobalt level of < 3 mcg/L. That Christy’s metal levels are elevated at all suggests that her hip is generating debris somewhere and given that she has a metal-plastic or metal-ceramic bearing couple it is likely that the debris is generated the modular junctions, either at the head neck couple, or at the neck body couple.The metal products generated at the couples tends to be more reactive that that generated at metal-metal bearing surfaces.
Christy can also request her X-rays, I can review them in the context of her implant inventory.
If Christy does get a MSMRI she ought to do some research that the machine and the imaging protocol at the imaging center are current, otherwise the study may be a waste of money. Dr. Hollis (radiologist) is the authority on imaging protocols for hip implants, her work will come up with a “Google Scholar” search. Within my community some imaging centers produce excellent images and some do not. I have found the high quality studies to be very helpful. The imaging time is significantly longer to get a proper study (upward of 45 minutes), a good opportunity to take a nap. There is no exposure to radiation with an MRI, just a magnetic field.
My suggestions are consistent with the recommendations that Styker sent to all of the surgeons known to use Stryker’s implants..Her surgeon’s attention should be directed towards the letter that Stryker likely sent him. If Christy’s surgeon remains reluctant to pursue the recommended imaging she might try to find another surgeon with a specific interest in revision hip arthroplasty. Surgeons that put the Rejuvenate stems in my be in a state of denial, it is human nature not to go out of ones way to find trouble. Addressing premature failure of a hip implant is a time consuming and painful process for the surgeon, the patients are (understandably) distressed about the prospects of a possible early revision surgery and the added hassle and expense of the metal level determinations and the MSMRI. The Stryker stems used with the modular necks can be difficult to extract, particularly if they have been in for a while because the bone grows into the implant surfaces very well with this design (a desirable thing unless one needs to be removed). The last one I took out, just removing the stem took several hours, so the entire time to revision the hip took about four hours (twice the time of a typical first time artificial hip operation) and I am very experienced with this type of operation. If Christy needs to have the hip revised she ought to find a surgeon that is experienced at doing hip revisions, her surgeon may or may be her ideal surgeon to do the revision.