BHR Hip Life?

[jmckeague]

Hi Forum,

I recently had right BHR, will likely schedule left BHR for end of year. Per my doctor, my condition is partially genetic, partially due to years of triathlons and marathons.

What I am trying to understand is the cause and relationship of wear on BHR joint. Example - if I wait until a year as recommended to start running again, and I run a series of Sprint tri's with related training, do I shorten the BHR joint from 20 years to 10 years? Shorten from 20 to 18? What is the tradeoff? I have found qualitiative comments but no hard data...

Also, what actually happens when a BHR fails? Does the joint begin excessively "click" and not glide smoothly?

Thanks John

[hoyt66]

Great question. I'll be watching this thread for sure!

[hernanu]

Hey John - welcome to the site and congrats on the HR. I'm sure there's all sorts of components that lead to OA, but there's really no consensus on a cause. I talked to my surgeon recently, and he's had a good number of martial artists who also have the issue. My brother in law and I (both black belts) have had surgeries, but my father, at age 77 is trucking along (he is a jiu jitsu black belt). No idea why.

The reason there's no long hard data for more than 10 years is that this is a young procedure, and hard data is not available in large samples for more than that. You can take a look at the Australian registry, which is very comprehensive, they have about 10 years worth of data.

You're looking for very specific data. To look at that, we'd need to take the data from the Australian registry, for example and mine it for pertinent data sets. Over the 10 years, to isolate the competitive runners from the recreational and those who don't. Then do a comparison for rate of failure (revisions) over time and by cause. Then we may be able to identify the impact of increased running over time, if there is any.

I prefer to think that probably by one and very likely two years, the bone has annealed to the prosthesis tightly enough that it mirrors the failure rate of bone itself, and hopefully our running hippys are in great bone shape and will continue to be so.

Good question, though - but it's probably going to be answered by our generation of hippys.

[Baby Barista]

As a 37 year old with a BHR, this was something I was very curious about too. I wondered, "If I put this off as long as possible, will I stand a better chance of never having a revision?"

My surgeon, Dr. Pritchett, told me that a BHR performs better in a 40 year old than a 50 year old, a 50 year old better than a 60 year old, etc. The evidence is primarily anecdotal, but strong. There are several factors in the performance of the prosthetic in a younger person, they include: overall health, strength, flexibility, bone density, and tissue resiliency.

[John C]

Here is one of the few published studies that goes directly to your question. Worth noting that one of the Doctors involved in the study was Dr Harlan Amstutz, who first started working on resurfacing back in the 1970s, and is often thought of as one of the forefathers of modern resurfacing.

Presentation Abstract      


Session:    15-Adult Reconstruction Hip II
Date/Time:    Wednesday, Feb 08, 2012, 11:06 AM -11:12 AM
Presentation Number:    216
Title:    The Relationship of Sporting Activity and Survivorship after Hip Resurfacing
Classification:    Adult Reconstruction Hip
Keywords:    Outcomes; Complications; Hip
Author(s):   Harlan C. Amstutz, MD, Pacific Palisades, California, United States
Michel J. Le Duff, Glendale, California, United States
Regina Woon, Los Angeles, California, United States
Alicia J. Johnson, BA, Los Angeles, California, United States
Abstract:    INTRODUCTIONThe effect of sports on the durability of the prosthesis after hip resurfacing has not yet been studied. This study correlates sporting activity levels computed as impact and cycle scores (ICS) with the survivorship of the procedure.
METHODSA total of 445 patients filled out a sport-specific survey between one and five years after surgery and were then followed clinically for a mean of 10 years. The mean age of the patients was 48.7 years and 74% were male. The ICS included two scores: an Impact Score (IS) and a Hip Cycle Score (HCS). All patients were also evaluated with the UCLA activity score. Twenty-three patients (27 hips) underwent revision surgery after filling out the survey.
RESULTSThe mean time of follow up at the time of survey data collection was 1.8 years (1.0 to 4.9) and the mean time of the follow-up period was 10.1 years (6.1 to 13.7). The mean IS was 28.1 (0 to 128) and the mean HCS 33.1 (0 to 144). Positive correlations were found between UCLA activity score and IS (r=0.535) or HCS (r=0.497). After adjustment for femoral component size, body mass index (BMI) and femoral defect size, a 10-point increment in IS corresponded to a 37% (95% CI 1.18 to 1.59) increase in the risk of revision while a 10-point increment in HCS increased the risk of revision by 22% (95% CI 1.06 to 1.41). Patients with an IS less than 50 had a risk of revision 3.8 times (95% CI 1.6 to 8.9) lower than the patients with an IS of 50 or greater, with a survivorship rate at eight years of 96.4% (95% CI 93.6% to 98.0%) vs. 88.8% (95% CI 74.7% to 95.3%). No association was found between UCLA activity score and survivorship of the procedure.
DISCUSSION AND CONCLUSIONHigh levels of sporting activities can be detrimental to the long-term success of hip resurfacing arthroplasty, independently from other risk factors. Patients seeking hip resurfacing are usually young and should limit their involvement in sports to levels that the construct will be able to sustain.

[Dannywayoflife]

John,
        When looking at the longterm longevity of the BHR the data only goes to around 16 years and for around 20 years with the previous devices. However if you look at the data from the surgeons who have been performing this proceedure the longest (ie McMinn and Treacy) then their long term data is VERY VERY encoraging! The beauty of the BHR is the massive ammount of associated clinical data. The BHR is based on known longterm clinical succeses. The alloy used in the BHR was used in several THR's that lasted 40+ years. There are numerous THR's still in situ after over 40 years.
The BHR is designed to work with a fluid film lubrication regime. So if your surgeon implants it as designed then most of the time theres no contact between the components. In fact ive heard it suggested by surgeons the more that you use a BHR the less it will wear. This is because the device will pull in more synovial fluid.
If you get the best surgeon you can find (preferably one who has done over 1000 with good track records) and use a proven device like the BHR then you will get a long lasting device that will allow you to enjoy your active life style.
Danny

[Miguelito]

Danny,
Would just synovial fluid prevent the components from touching? I've heard (repeatedly) that all implant surfaces wear. Wouldn't wear just be a symptom of the components touching?
Mike

[Dannywayoflife]

Hip resurfacing devices work with a mixed lubrication regimine. When in motion they draw synovial fluid into the device and the components then hydroplane. There will always be some wear but the wear of these devices really is miniscule! I read about a THR that was made from the same alloy as the BHR which was recovered after i think 27 years in situ the measureable wear was just 20+ microns!!! Now a micron is 1 millionth of a metre or 1 thousandth of a MM!!!! Realisticly i doubt that its humanly possible to wear these things to a point where they will fail to work. My personal take is that long term bone health is the most important factor. I think that the bone clinging on to the components and not wear is the real test.

[Tin Soldier]

Excellent discussion.  McMinn's data set is probably the longest, most encouraging, and most talked about dataset as Danny points out.  In 2012 McMinn reported 98% succes for 14 years and I believe that was about 3000 HRs?  Something of that nature.  The Australian registry is often referenced also, but as some of the really experienced surgeons will point out, the national registries have a lot of variability which comes from multiple surgeons with a variety of experience levels, a variety of different patient lifestyles and age,...  I think it's a little harder to find conclusive results in the larger datasets.  On the other hand, I think we need to get rolling on a registry in the US.  As Hern points out, many of us are the next generation of HR and 10 to 20 years from now it would be nice to have a large dataset with lots of parameters so that we really can pull conclusive data out about running too much, angles, age, or ...

I like Amstutz's conclusions in that it's not a bad idea to take it down a notch on impact sports, running,...merely for the fact that it seems like common sense, the more impact to a device, the more wear.  However, McMinn beat the crap out of the BHR prototypes with a 500 lb weight with no fluid, pig synovial fluid, human fluid,... and found very little wear.  Basically CoCr alloy is very long lasting and wear-resistant. 

The failures tend to be related to adverse tissue reactions which have been suggested to be related to high cup angles and thus added wear (edge loading).  This might be where the idea of syn fluid getting "sucked" into the component is good, but at the edges you might lose some of that fluid layer and cause more wear.  The added metals in the area can then cause adverse reactions.  I'm not sure about the details on that, but I think there are more recent studies that look at the mechanics in more detail.

The device doesn't actually fail, it's the tissue around the device that fails.  It can't handle the elevated metals from the extra wear.  I think the clicking is more related to inflamed tissue and not an actual mechanical failure of the device.  I suppose it could also be related to the cup lossening in the bone from general degradation of the joint.

Thanks for the discussion.   

[jmckeague]

Thanks all, this dialogue is extremely helpful. Obviously, there are few absolutes in life, but this provides great directional guidance. It seems counter-intuitive that bone/calcium would have greater wear life than highly engineering alloys. I also found it curious that the mfg'ers product info (Smith and Nephew) commented on, sort of approved, jogging after the year long recovery, but each of the five doctor opinions I sought discouraged without exception any impact activities.

I am sure liability weighs into the discussion.

Anyways, much appreciated....

[Miguelito]

As always, I am not a doctor, but I suspect that the cartilage that typically coats both sides of a joint is an amazing surface (and very slippery) that will not be successfully artificially replicated for a while yet, if ever (though they will probably be able to regrow it even within my lifetime, or my children's.)

The human body is an amazing machine. Just out in the yard casually picking up the kids balls/toys I can pick up a dozen or so different things in each arm, using various pressures with bicep muscles, or forearm muscles, or fingers, or the side of a hand. There is just no way they will be able to create a machine that could do all those different subtle things, certainly not for the next fifty years. On the other hand, my smartphone pisses all over the communicators they had on the old Star Trek show...

[Dannywayoflife]

Thanks all, this dialogue is extremely helpful. Obviously, there are few absolutes in life, but this provides great directional guidance. It seems counter-intuitive that bone/calcium would have greater wear life than highly engineering alloys. I also found it curious that the mfg'ers product info (Smith and Nephew) commented on, sort of approved, jogging after the year long recovery, but each of the five doctor opinions I sought discouraged without exception any impact activities.

I am sure liability weighs into the discussion.

Anyways, much appreciated....

I asked Mr Treacy weather my activity levels that I spoke to him about were realistic and he didn't bat an eye lid. He only really said he doesn't like people running marathons all the time or playing rugby. But was fine with recreational running and other high impact after 12 months.

[Tin Soldier]

Also, speaking of the natural materials, synovial fluid is thixotropic, meaning the harder you hit it, the more resilient it is.  Or it acts as a solid when hit hard, but acts like a fluid with normal light movements.  Like corn starch and water.  I wonder if that is the key to saving your cartilage, dunno.  I do know that syn fluid injections cost a lot, because you have to extract the juice from chicken combs and chicken beaks. 

With a new metallic hip with micron spacing, I think you loose much of that added thixotropic property.  You still get your lubrication.  Not quite sure where I'm headed with this, but I could see some docs being more concerned about impact sports than others, and it might be based on some of what I'm arm-waving about.

Beam me up, Scotty!

[Jason0411]

McMinn explained to me the lack of wear was basically due to the alloy used and the fact that as Danny said the components should not actually touch. The fluid not matter how thin creates a barrier between the two components. You don't need much water under your tyres on a smooth road surface to aquaplane and the smoother it is the less you need.
Those BHRs are pretty bloody smooth.

[Dannywayoflife]

That's right jason, the alloy used in the BHR has a massive amount of clinical data behind it. Vitallium is known as a stellar alloy.