June 13, 2025 • 29 mins
In this episode of the AHF Podcast, host Joe Schwab delves into the controversial topic of hip resurfacing with special guest, Professor Justin Cobb, an orthopedic surgeon and chair of orthopedics at Imperial College London. They discuss the history, challenges, and advancements in hip resurfacing, including Professor Cobb's work on the H1 ceramic-on-ceramic hip resurfacing. The conversation covers the intricacies of hip function, long-term outcomes, and future directions in hip arthroplasty. Don't miss out on this insightful discussion!
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Episode Transcript
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Joseph M. Schwab (00:24):
Hello everybody and welcome to the AHF
podcast.
I'm your host, Joe Schwab.
Few topics in modern hip surgeryseem to strike up as much
controversy as hip resurfacing.
Hip surgeons have been trying tosolve this since, at least as
far back as the 1920s, with bothMarius Nygard Smith Peterson in
the US and Ernest Haygrove inthe uk, independently reporting
(00:47):
on work they had been doing torestore function to arthritic
hips, using things like glassand ivory.
We've seen mold arthroplasty,cup arthroplasty, double cup
arthroplasty, and more using.
Materials from acrylic to Teflonto stainless steel and cobalt
chrome.
With the introduction of moremodern metal on metal implants
(01:08):
like the Birmingham hipresurfacing or the Conserve
Plus, starting in the mid 1990s,hip resurfacing seemed to
undergo not only a renaissance,but a considerable spike in
popularity, thanks to thepurported advantages of bone
preservation, anatomicrestoration of joint mechanics,
and a very stable head to shellratio.
(01:28):
With renewed interest, however,came some renewed scrutiny and
with a growing number of designsin the marketplace, it was clear
that small design differenceswere associated with
substantially different results.
Some designs like the A SR we'reseeing 10 year revision rates
nearing 50% failures associatedwith the bearing surface.
(01:49):
Materials seem to be a commontheme though to be fair.
Not all designs exhibited thesame problems.
So why do we come back to thisconcept year after year, decade
after decade?
That's the question for my guesttoday.
Professor Justin Cobb is anorthopedic surgeon and chair of
orthopedics at Imperial CollegeLondon.
(02:10):
Not to mention the fact he'sbeen orthopedic surgeon to Queen
Elizabeth II, as well as KingCharles III.
But most important to ourdiscussion today is that he's
been working to develop the H1ceramic on ceramic hip
resurfacing.
And with that, he hopes to bethe surgeon who finally cracks
the code for a reliable,reproducible and durable hip
(02:32):
resurfacing implant.
Professor Cobb, welcome to theAHF podcast.
Justin Cobb (02:38):
You are very kind, delighted to.
Joseph M. Schwab (02:41):
So depending on who you talk to.
Hip resurfacing is eitherpotentially the pinnacle of all
hip surgery, or it's anunmitigated disaster.
Could you put hip resurfacing ina context that seems reasonable
for the rest of us?
Justin Cobb (03:00):
Yeah.
So.
Um, I really got, um, convincedabout, um, hip resurfacing when
measuring function in our gaitlab.
And we looked at, I was, I got,it was very keen on resurfacing
from, I guess around about 2000.
It felt like a more conservativeprocedure and, but as you
(03:22):
pointed out, many surgeons neverreally got on with it.
And one of my friends who's avery good hip surgeon, thought
it was the invention of the duand we really had parallel
practices, same patient groups.
I was resurfacing, he wasreplacing.
And then the, and we, I got a, agrant paid for a, um, a, a
(03:43):
instrumented treadmill so wecould see how people walked, how
they went faster and faster.
And we weren't the, I think Ican safely say nothing I've done
has ever been the first in itsfield, but we showed what other
people have shown, which is thathealthy, normal people have got
this fantastic continuouslyvariable transmission gearbox in
(04:04):
their brain.
And when you put your foot onthe gas and walk faster and
faster, your stride length andyour cadence smoothly increase
until you start to run.
And what we find with healthyadults is that's what happens in
their thirties, forties,fifties, sixties, seventies,
eighties even.
That's what happens if you'vegot a stem in your femur that
(04:25):
doesn't happen.
Strolling is great on thecatwalk.
Nobody can tell.
But if you wanna push, put yourfoot on the gas, the person with
a hip replacement with a stem intheir femur, and I'm, I don't
think it's really, I'd love tosay it's just because of the
anterior posterior approach, itdoes seem to be the stem in the
(04:46):
femur.
I think, um, with a stem in yourfemur, once you start to stress
the elasticity of the femur, um,it doesn't feel, people don't
report pain.
They just don't do it.
So they don't push off so hardwith the stem in their femur.
But the resurfacings, hugeposterior approach taking down
gmax tendon, huge approach.
(05:09):
A year later, they're walkingvery, very close to normal
people in a way that no one'sever published a total hit that
can do that.
So that was, that was data.
I was, and I, this was in theearly two thousands and it was
really exciting, the stuff.
But as you pointed out, themetal or metal debacle.
(05:30):
Um, meant that all of thesepatients, um, who were doing
great, if you did it accurately,um, they were okay, but there
was a growing feeling across thewhole world that metal irons
were bad.
And so it was increasinglydifficult to persuade people to
(05:52):
have a, a procedure.
And certainly in Britain therewas an advisory.
You had to have a metal landlevel test every year implying
that you had a pros, aprosthesis that was about to
explode.
And so the metal work, it was,it was never going to be widely
adopted around the world as, asyou found out.
But functionally, and the totalhip industry has done a, I mean,
(06:17):
as you know, in the anterior hipfoundation, I'm a huge fan of
the insult to the patient foranterior hip surgery is minimal.
But in the end it's a hipreplacement.
And if you cut out someone'scalcar, which is the strongest
bit of the whole femur and youde power that calcar, you don't
(06:37):
let the femoral head take allthe force coming from your
flexors and abductors.
If you de power that, then youare, you are changing the
biomechanics irreversibly.
Whereas if you just resurfacethe hip, um, you can allow that
femur to perform like a normalfemur.
And I think that's thedifference.
Joseph M. Schwab (06:57):
So, so this is interesting'cause when I look
online at discussions, forinstance, every once in a while
you'll see a, a post on LinkedInwhere somebody puts up, um, an
x-ray of an arthritic hip andsays, should they get a total
hip?
Should they get a hipresurfacing?
And the discussion always comesdown to recovery with many
surgeons feeling like therecovery is simply easier with a
(07:19):
hip replacement than it is witha hip resurfacing.
But it sounds like you'retalking more long-term
functional recovery with peoplegoing back to normal, as opposed
to what happens in the shortterm.
Is that right?
Justin Cobb (07:33):
Um, I was until, um, uh, a couple of years ago, I
would've said what you said isabsolutely right, that with an
anterior approach, total hip,you are up and going very, very
fast and with, with aresurfacing your, you are a bit
slower off the, off, off.
You're not, you, you probablyare a slower.
(07:56):
I don't think there's asignificant, I think if anything
resurfacing are a bit quicker.
Joseph M. Schwab (08:01):
Well, and that, that actually brings up
the other part of the discussionthat I usually see is when
somebody talks about aresurfacing, it's almost placed
as an anterior approach, and hipresurfacing are at odds with
each other.
They're competing products, soto speak.
But I mean, really what you'retalking about is doing the
surgical approach of an anteriorapproach to put in a, a bone
(08:24):
conserving, hip resurfacingimplant.
Is that correct?
Justin Cobb (08:28):
That's right.
Joseph M. Schwab (08:29):
Yeah.
So how do you think we shouldapproach that discussion with
those surgeons, you know, onlineabout, uh, anterior approach,
sort of versus hip resurfacing?
Justin Cobb (08:41):
so you and I, as surgeons, we know we really can
only sell the shoes in our shop.
And if, if you can't do anoperation, you brief against it
pretty vigorously.
Joseph M. Schwab (08:53):
Yeah,
Justin Cobb (08:54):
If you are a key opinion leader for a total hip
arthroplasty, you better notpromote something that the
company that is paying you bigbucks doesn't even have in their
arsenal.
So I think the online chat is,some of it is, I mean, some of
it is real truth if you likepeople talking from their own
(09:18):
personal experience and some ofit is industry based noise slash
testosterone fueled egos
Joseph M. Schwab (09:27):
That brings me to the H1 specifically.
'cause uh, you know, one of the,uh, one of the things that
you've been working on is thedevelopment of this, uh,
product.
And can you, first of all, canyou tell our listeners, um, a
little bit about the product anda little bit maybe about the
release schedule for it?
'cause it's not availableeverywhere at this point, is
(09:49):
that correct?
Justin Cobb (09:50):
It is not available anywhere at this point,
unfortunately.
I mean, so Derek McMinn, who'sa, um, uh, obviously very senior
and August, but nevertheless,dear friend, um, Derek, when he
was developing the Birmingham inI think six years, went through
five major changes, cementing,uncementing, uh, different
(10:11):
designs.
These days, so we, we startedwith H1 in earnest with Ceramtec
in 2013
Joseph M. Schwab (10:19):
Yeah.
Justin Cobb (10:20):
and really working very hard to get it into people.
We got our first patients of thesummer of 2017, and we got a CE
mark, um, September of lastyear, and we expect it will be
released in, I, we hope, sixdifferent European countries,
(10:42):
including Switzerland.
Um, this autumn.
So the, the, the program of, um,regulation is just brutal.
It's absolutely brutal.
And I'm very sorry.
The, the FDA, when we last spoketo them, they'd all just had a
letter of Elon Musk saying, whatare you doing every day?
(11:02):
And,
Joseph M. Schwab (11:03):
yeah.
Justin Cobb (11:03):
and we were speaking English and they were
speaking American.
And it was a very uncomfortableexperience.
I mean, I really, I've never hadthat experience before.
Very uncomfortable.
Joseph M. Schwab (11:11):
So, uh, let's talk a little bit about the, the
H1 itself, because like yousaid, you partnered with
Ceramtec and so the, theprosthesis itself, the bearing
surface is the Biolox delta,right?
Justin Cobb (11:24):
the, the device is monolithic Biolox Delta, which
I've been using actually.
I used, I was very happy withForte before Delta came along
and, but Delta now we've got, Ithink there's 13 or 14 years of
experience and, and tens ofmillions of people with Biolox
Delta in their bodies.
(11:44):
So it seems like it's quite asafe material.
Um, and so we felt verycomfortable, um, going to them.
So they.
The device, it's then coated inMedicoat.
Medicoat was set up in justoutside Zurich to coat, actually
it was set up by, um, Haki, um,Gruner to, to coat the furlong
(12:09):
ha coated, um, uh, hip back inthe eighties.
And his son Philip, runs thecompany now and they, they've
been coating Titan Tanium for avery long time and coating
directly onto green machinedceramic that is new, but it
seems to be, um, it seems to be,you know, if you do the testing,
(12:34):
you can rip it off, you canshear it off, and the forces
needed to, to take it off are abit greater.
Well, there's equivalent orderof magnitude to ripping off, uh,
plasma per titanium fromtitanium or cobo creme.
It's a very, very strong bond.
Um.
But adhe, the, if you, I don'twanna talk about adhesion
science.
(12:54):
It's very, very niche.
It's way outside.
Orthopedic surgeons pay grades,
Joseph M. Schwab (12:59):
But, um, suffice it to say you can,
you're putting these in withoutthe use of cement, correct?
Justin Cobb (13:04):
so both sides.
So I had good experience withCementless, um, metal and metal
resurfacing, and Paul Beaule in,in Ottawa, who's a real giant in
this world.
He, he's got, again, very goodexperience with the Conserve
plus Cementless.
Um, Tom Gross with, uh,cementless Recap in South
Carolina.
(13:25):
Um, KDA met in, in Gent has had,I think he's done all three of
those, um, cementless.
And it seems to, it seems asthough the Cementless feral
component, it's a safeconstruct.
And so we have the experiment ofplasma spray titanium on ceramic
on both sides.
So a single experiment, whereas.
(13:46):
We felt that going cemented.
That would be an experiment too.
No one had ever got a devicecement onto ceramic.
That would be a new one too.
Joseph M. Schwab (13:54):
Why ceramic as the bearing surface?
I mean, you have, I presumablythere are a number of different
options you could haveconsidered.
Why did you choose ceramic?
Justin Cobb (14:04):
yeah, so obviously initially, honestly the first
thing that came along was thecontour.
So in the old days, in fact inthe current resurfacings and
with total hips, two groin painis a thing in hip arthroplasty
and it's between sort of threeand five times as common.
Sorry, commoner in, inresurfacing arthroplasty.
(14:27):
Um, and that's partly, it lookslike it's mainly the acetabular
rim.
You know, it looks like ifsomeone sort of growing pain,
you probably didn't get thatanterior rim inside the pelvis
enough.
Um, and we.
Back in 2007, well done,actually one of my PhD students,
um, and I, we looked at thecontour and we realized it was
(14:50):
quite a mathematical contour.
And so we, we, we patented thatin 2007 and I wanted to do it
with metal on metal, but as wewere doing, it was obvious
metal, metal was going nowhere,and so a contour metal on metal
was never gonna run.
So we then looked the differentmaterials.
As I'm sure you know, the polymotion is in use in North
(15:13):
America right now.
There's an IDE going on in NorthAmerica, which is a metal on
highly cross think poly, um, butwhat we, in our preclinical
testing, um, it, one of thethings about the, the group of
people who want really benefitfrom resurfacing are the young,
very active men with cams, allof whom have quite shallow
(15:33):
sockets.
And the young, very active womenwho, some have got cams, but
quite a lot haven't.
They've just got a bit ofdysplasia, quite a shallow
socket and leaving.
So you have to have theopportunity to leave some
substantial amount of uncoveredbone uncovered prosthesis
laterally to give them the goodarticulation and that
(15:57):
unsupported polyethylene, um,the preclinical testing, it just
fails it.
So we unsupported, metal backed,it doesn't fail it, but without,
um.
Metal backing.
We couldn't get polyethylene toto, to succeed.
So we had to go to hard on hard.
And in Europe, I think in everycountry in Europe, ceramic and
(16:17):
ceramic is a well established,um, bearing couple.
It's only really in NorthAmerica that doesn't, doesn't
accept that as a regular thing.
Um, in Europe, um, we've all gotreally good experiences, I think
of, of, of c ceramic bearings.
And so we went to that and, andin fact the un unsupported, um,
(16:41):
rim, it's a really, you've gottahave the ability to have a cup
that is unsupported in mild oreven moderate dysplasia that is
not gonna fail.
Joseph M. Schwab (16:52):
So do you think the reason, um, the, the,
is the primary reason that thecups were sort of exposed
anteriorly or groin pain wasoccurring anteriorly more common
in resurfacings because of thematerial, because of the shape
of the device or because of thesize of acetabular prosthesis
(17:12):
relative to a more conventionaltotal hip or a combination of
those
Justin Cobb (17:16):
Combination.
Combination.
So, um, I wanted, I'll send youa last picture showing the, um,
uh, of an acetabular componentof a metal, metal one and our
contour.
And the fact is, if you haven'tgot a cutout for the oop pubic
recess anteriorly, where the Scomes and the ichi, it's much
(17:40):
more gradual recess posteriorly.
If you haven't got thosecutouts, you've gotta put the
socket a long way further in toavoid, avoid, um, conflict.
And we can, we can leave thecenter much more where it wants
to be with the contours.
Um, so, so I think it reallymakes a substantial difference
(18:03):
to the surgeon trying to get thesocket in the right place
because it doesn't have tooverhang except to give you back
your, your where whale scar was.
You've now got a lovely big, um,peninsula there, but you haven't
got overhang for sos um,anteriorly.
Joseph M. Schwab (18:19):
Interesting.
So you, you briefly mentionedindications and, and let's,
let's talk about this because,um, indications over time for
hip resurfacing kind of shranksubstantially, uh, from
everybody can get it to, youknow, maybe males with a larger
bone size and their, you know,who are very active in their,
(18:41):
you know, fifties to sixties,forties to sixties.
It's different depending on theliterature you look at.
But certainly over the last 20years, the relative indications
for a traditional hipresurfacing contracted.
From your perspective and withthe development of the H1, does
it address some of the reasonsfor those, uh, changes in
(19:02):
indications and what are your
Justin Cobb (19:04):
so so the, it, it wasn't so much the indication, I
think it was the, as the truthof the matter, the problem was
edge loading of the wear scar ina metal or metal bearing.
That was the problem.
That was the only problem.
And to get a, and I've gotseveral very, um, prominent
female athletes and dancers andso on who are 10 and 15 years
(19:26):
after every resurfacing, doingjust great.
But you had to get the socketorientated, right?
You didn't get it right.
They got, um, um, high Medlinelevels and Tom Gross has
published on this, and he is areal master of this.
Um.
So the indication in women isvery strong.
(19:46):
If there isn't acontraindication, the
contraindication of a, um, auniform thickness metal bearing
couple means you've just gotthis very small surface area on
the smaller sizes.
With ceramic, ceramic, the rulesare completely different with
literally, I think I don't, withmillions of ceramic and ceramic
bearings with decades in humans,the case report of edge loading
(20:11):
of runaway wear has yet to bepublished.
And because we all love badnews, you know, we all love bad
news.
If there was bad news, theceramic and ceramic haters would
be putting up pictures of edgeloading of runaway wear on every
talk they gave.
But it seems to be a, a, a amore, a much, much more benign
(20:31):
tribal environment.
Um, so the worry about edgeloading of runaway wear doesn't
seem to be there.
And so for women.
Um, resurfacing is a greatoption for women.
It really is.
It's fantastic.
And unlike the sporting, um, we,uh, athletic man, women live
(20:54):
forever.
Okay?
They're never gonna die.
And, and to cut large bits outof them, um, unnecessarily, it
seems like a big mistake.
So, so our indications areadequate bone mass.
And the one thing that gives methe heebie-jeebies is
(21:14):
bisphosphonates someone who'shad bisphosphonates
preoperatively.
I think that's a.
I, I don't that, that's adifficult, I, I think it's just
too scary for us right now.
Um, but if someone's got a, ifthey're a healthy adult, that
means that we know Wolf's lawcarries on working in your
(21:34):
nineties and hundreds.
You know, if you are active, youkeep your bones active.
So, so, um, in our trial we had70 as the upper age limit.
Um, and I, I had one, um, builtmuscular Californian man who
literally sent money trying toBri he was 72 trying to bribe
(21:57):
his way onto the study.
Um, and so since the trial, Imean, people in their seventies,
as you know, there are lots ofreally good people in their
seventies.
And to say to them, no, you'vegotta have your femoral head and
neck cut out and someone bang abig bit of metal into their fma,
well, you know, you don't haveto have that, I don't think.
Joseph M. Schwab (22:16):
I suppose how, how about things like, um,
certain types of pediatric hipdeformity.
So you said adequate bone stock,is that just dealing with
osteoporosis or things likeperthes, advanced Perthes and,
Justin Cobb (22:29):
So the planning, I mean the, the we've done a
really difficult per is isreally difficult.
It's really hard.
Um, of course it is.
And so there's some things thatare just too difficult and you
can't do very much withpeople's.
Um, you know, you can't do whatyou can do with an estro with
(22:49):
resurfacing, of course youcan't.
But I have, um, done correctiveosteotomies and resurfacing, um,
simultaneously with fractures ofthe proximal femur.
I think that's something you cando, um, and just resurface the
feral head.
Um, but I think in bad path, Imean, and bad av n too, of
(23:10):
course you can't use it forthose things.
Joseph M. Schwab (23:12):
So do you look at version of the femur?
Um, for instance, before you're,when you're planning for a, a
hip resurfacing, would youcorrect a femoral version?
Or obviously you're not gonna dothat through the prosthesis, um,
but or do you just prefer to putthem where they anatomically
came from?
Justin Cobb (23:29):
So it's a great question, and in, in really bad
DDH with huge, um, femoralinversion in my old days of
metal on metal, um, I, on acouple of occasions did a
rotational osteotomy of thefemur the same time as, um,
during the resurfacing.
I haven't seen, you know, it'sa, it's a real question, but I
(23:52):
just haven't seen that for awhile.
Um, and I, but I think the rulesare the same in all
arthroplasty.
You've got to give somebody abiomechanically sound, um,
reconstruction, which mayrequire corrective osteotomy,
Joseph M. Schwab (24:09):
I think, um, the, the kinematic alignment
total knee folks are challengingour conventional wisdom as to
what, uh, biomechanicalsoundness is.
And, uh, I, I, I find thatinteresting as well from a total
hip
Justin Cobb (24:21):
for the, from the femur, you know, the, I I hope
we're gonna publish quite soon,some more work on, on the, the
elasticity of the femur and, um,and the, the, the impact of e
femoral stem on that, on thebiomechanical properties of the
femur.
Um, and if you've, if you cansave the compression trabecula
(24:46):
from the car, car going up ontothe femoral head, if you can
save those, then your hip flexesare just driving straight up
them.
If you cut them off, they'vegotta go down into the.
Um, shaft to bond onto themetalwork and then go back up.
It's just, it's a tortuous routefor the forces to be delivered.
Joseph M. Schwab (25:07):
you've mentioned briefly your
detractors, uh, well, you saidsort of jokingly, you know, if,
if detractors were finding theseproblems, of course they'd be
bringing'em up online.
I.
I'm certain you must have runinto some detractors in during
this development period for somereason or another.
What are they saying and hastheir message changed over time
or has it gotten louder orquieter?
(25:28):
What would you say?
Justin Cobb (25:31):
um, I think I got, I've gotta be, um, gotta be
polite.
It's DA data.
You know, there are big hipgroups that publish huge amounts
of stuff that have neverpublished any outcome data.
Not not revision rates, butactually outcome.
(25:55):
And if you look at the Swedishregistry, and the Swedes have,
have done a pretty, a very goodjob of looking at how their
patient's doing, not justrevision rate, but everything
else in their registry.
Um, the, uh, cemented stem isn'tthat great, you know,
functionally in terms of outcomestudies.
(26:15):
They're not that great andcement less stems seem to be
better, but not as good asresurfacings in functional
terms.
Now, of course, there'sselection bias and all that.
Of course there is, but no one'sever done the other way around.
No one's ever shown, um, thatthe, the resurfacings do really
(26:37):
badly, um, functionally.
Um, and so to say, I insist oncutting out your femoral head
and, and fossilizing the insideof your proximal femur.
So the big arguments in Britain,honestly, it's about cemented
stems.
Can you believe that?
Um, it's amazing.
(26:57):
They really are devoted to that.
Joseph M. Schwab (27:00):
Is there, um, do you have any thoughts or
plans on, um, uh, turning the H1into, uh, sort of a smart
implant or something that hassome built in sensors so you can
understand, um, maybe a littlebit more in depth what the
interface with the bone is like,what the load transfers are
like, or any other, um, uh, anyother changes to the
Justin Cobb (27:24):
So, I mean, it's a really interesting, it's a
really interesting question.
I, I feel the, um, because youare just putting a coating on
the, on that femoral head, um.
It behaves, it behaves very likea normal femur.
It really does.
Um, and I think it's a, I thinkthe, I mean the thought of going
(27:47):
through ethics and the, all thedevelopment pathway to get the
strain gauges into something inthe femoral head, I'm not up for
that yet.
I think when we've got, youknow, we've only got seven and a
half year results so
Joseph M. Schwab (28:01):
Yeah.
Justin Cobb (28:01):
and
Joseph M. Schwab (28:01):
Yeah.
Justin Cobb (28:02):
nobody thinks that's long term.
I think if we absolutely knowwhat the 10 and 15 year results
are like, then I wouldn't feelbad about asking someone to do
that.
But for the moment, I think we,we, I wouldn't ask someone to
have that done.
Joseph M. Schwab (28:19):
Thank you for joining me for this episode of
the AHF Podcast.
Be sure to join me next week forpart two of my conversation with
Professor Justin Cobb.
Please take a moment to like andsubscribe.
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(28:41):
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(29:05):
I'm your host, Joe Schwab,reminding you to keep those hips
happy and healthy.
Hello everybody and welcome to the AHF
podcast.
I'm your host, Joe Schwab.
Few topics in modern hip surgeryseem to strike up as much
controversy as hip resurfacing.
Hip surgeons have been trying tosolve this since, at least as
far back as the 1920s, with bothMarius Nygard Smith Peterson in
the US and Ernest Haygrove inthe uk, independently reporting
(00:47):
on work they had been doing torestore function to arthritic
hips, using things like glassand ivory.
We've seen mold arthroplasty,cup arthroplasty, double cup
arthroplasty, and more using.
Materials from acrylic to Teflonto stainless steel and cobalt
chrome.
With the introduction of moremodern metal on metal implants
(01:08):
like the Birmingham hipresurfacing or the Conserve
Plus, starting in the mid 1990s,hip resurfacing seemed to
undergo not only a renaissance,but a considerable spike in
popularity, thanks to thepurported advantages of bone
preservation, anatomicrestoration of joint mechanics,
and a very stable head to shellratio.
(01:28):
With renewed interest, however,came some renewed scrutiny and
with a growing number of designsin the marketplace, it was clear
that small design differenceswere associated with
substantially different results.
Some designs like the A SR we'reseeing 10 year revision rates
nearing 50% failures associatedwith the bearing surface.
(01:49):
Materials seem to be a commontheme though to be fair.
Not all designs exhibited thesame problems.
So why do we come back to thisconcept year after year, decade
after decade?
That's the question for my guesttoday.
Professor Justin Cobb is anorthopedic surgeon and chair of
orthopedics at Imperial CollegeLondon.
(02:10):
Not to mention the fact he'sbeen orthopedic surgeon to Queen
Elizabeth II, as well as KingCharles III.
But most important to ourdiscussion today is that he's
been working to develop the H1ceramic on ceramic hip
resurfacing.
And with that, he hopes to bethe surgeon who finally cracks
the code for a reliable,reproducible and durable hip
(02:32):
resurfacing implant.
Professor Cobb, welcome to theAHF podcast.
Justin Cobb (02:38):
You are very kind, delighted to.
Joseph M. Schwab (02:41):
So depending on who you talk to.
Hip resurfacing is eitherpotentially the pinnacle of all
hip surgery, or it's anunmitigated disaster.
Could you put hip resurfacing ina context that seems reasonable
for the rest of us?
Justin Cobb (03:00):
Yeah.
So.
Um, I really got, um, convincedabout, um, hip resurfacing when
measuring function in our gaitlab.
And we looked at, I was, I got,it was very keen on resurfacing
from, I guess around about 2000.
It felt like a more conservativeprocedure and, but as you
(03:22):
pointed out, many surgeons neverreally got on with it.
And one of my friends who's avery good hip surgeon, thought
it was the invention of the duand we really had parallel
practices, same patient groups.
I was resurfacing, he wasreplacing.
And then the, and we, I got a, agrant paid for a, um, a, a
(03:43):
instrumented treadmill so wecould see how people walked, how
they went faster and faster.
And we weren't the, I think Ican safely say nothing I've done
has ever been the first in itsfield, but we showed what other
people have shown, which is thathealthy, normal people have got
this fantastic continuouslyvariable transmission gearbox in
(04:04):
their brain.
And when you put your foot onthe gas and walk faster and
faster, your stride length andyour cadence smoothly increase
until you start to run.
And what we find with healthyadults is that's what happens in
their thirties, forties,fifties, sixties, seventies,
eighties even.
That's what happens if you'vegot a stem in your femur that
(04:25):
doesn't happen.
Strolling is great on thecatwalk.
Nobody can tell.
But if you wanna push, put yourfoot on the gas, the person with
a hip replacement with a stem intheir femur, and I'm, I don't
think it's really, I'd love tosay it's just because of the
anterior posterior approach, itdoes seem to be the stem in the
(04:46):
femur.
I think, um, with a stem in yourfemur, once you start to stress
the elasticity of the femur, um,it doesn't feel, people don't
report pain.
They just don't do it.
So they don't push off so hardwith the stem in their femur.
But the resurfacings, hugeposterior approach taking down
gmax tendon, huge approach.
(05:09):
A year later, they're walkingvery, very close to normal
people in a way that no one'sever published a total hit that
can do that.
So that was, that was data.
I was, and I, this was in theearly two thousands and it was
really exciting, the stuff.
But as you pointed out, themetal or metal debacle.
(05:30):
Um, meant that all of thesepatients, um, who were doing
great, if you did it accurately,um, they were okay, but there
was a growing feeling across thewhole world that metal irons
were bad.
And so it was increasinglydifficult to persuade people to
(05:52):
have a, a procedure.
And certainly in Britain therewas an advisory.
You had to have a metal landlevel test every year implying
that you had a pros, aprosthesis that was about to
explode.
And so the metal work, it was,it was never going to be widely
adopted around the world as, asyou found out.
But functionally, and the totalhip industry has done a, I mean,
(06:17):
as you know, in the anterior hipfoundation, I'm a huge fan of
the insult to the patient foranterior hip surgery is minimal.
But in the end it's a hipreplacement.
And if you cut out someone'scalcar, which is the strongest
bit of the whole femur and youde power that calcar, you don't
(06:37):
let the femoral head take allthe force coming from your
flexors and abductors.
If you de power that, then youare, you are changing the
biomechanics irreversibly.
Whereas if you just resurfacethe hip, um, you can allow that
femur to perform like a normalfemur.
And I think that's thedifference.
Joseph M. Schwab (06:57):
So, so this is interesting'cause when I look
online at discussions, forinstance, every once in a while
you'll see a, a post on LinkedInwhere somebody puts up, um, an
x-ray of an arthritic hip andsays, should they get a total
hip?
Should they get a hipresurfacing?
And the discussion always comesdown to recovery with many
surgeons feeling like therecovery is simply easier with a
(07:19):
hip replacement than it is witha hip resurfacing.
But it sounds like you'retalking more long-term
functional recovery with peoplegoing back to normal, as opposed
to what happens in the shortterm.
Is that right?
Justin Cobb (07:33):
Um, I was until, um, uh, a couple of years ago, I
would've said what you said isabsolutely right, that with an
anterior approach, total hip,you are up and going very, very
fast and with, with aresurfacing your, you are a bit
slower off the, off, off.
You're not, you, you probablyare a slower.
(07:56):
I don't think there's asignificant, I think if anything
resurfacing are a bit quicker.
Joseph M. Schwab (08:01):
Well, and that, that actually brings up
the other part of the discussionthat I usually see is when
somebody talks about aresurfacing, it's almost placed
as an anterior approach, and hipresurfacing are at odds with
each other.
They're competing products, soto speak.
But I mean, really what you'retalking about is doing the
surgical approach of an anteriorapproach to put in a, a bone
(08:24):
conserving, hip resurfacingimplant.
Is that correct?
Justin Cobb (08:28):
That's right.
Joseph M. Schwab (08:29):
Yeah.
So how do you think we shouldapproach that discussion with
those surgeons, you know, onlineabout, uh, anterior approach,
sort of versus hip resurfacing?
Justin Cobb (08:41):
so you and I, as surgeons, we know we really can
only sell the shoes in our shop.
And if, if you can't do anoperation, you brief against it
pretty vigorously.
Joseph M. Schwab (08:53):
Yeah,
Justin Cobb (08:54):
If you are a key opinion leader for a total hip
arthroplasty, you better notpromote something that the
company that is paying you bigbucks doesn't even have in their
arsenal.
So I think the online chat is,some of it is, I mean, some of
it is real truth if you likepeople talking from their own
(09:18):
personal experience and some ofit is industry based noise slash
testosterone fueled egos
Joseph M. Schwab (09:27):
That brings me to the H1 specifically.
'cause uh, you know, one of the,uh, one of the things that
you've been working on is thedevelopment of this, uh,
product.
And can you, first of all, canyou tell our listeners, um, a
little bit about the product anda little bit maybe about the
release schedule for it?
'cause it's not availableeverywhere at this point, is
(09:49):
that correct?
Justin Cobb (09:50):
It is not available anywhere at this point,
unfortunately.
I mean, so Derek McMinn, who'sa, um, uh, obviously very senior
and August, but nevertheless,dear friend, um, Derek, when he
was developing the Birmingham inI think six years, went through
five major changes, cementing,uncementing, uh, different
(10:11):
designs.
These days, so we, we startedwith H1 in earnest with Ceramtec
in 2013
Joseph M. Schwab (10:19):
Yeah.
Justin Cobb (10:20):
and really working very hard to get it into people.
We got our first patients of thesummer of 2017, and we got a CE
mark, um, September of lastyear, and we expect it will be
released in, I, we hope, sixdifferent European countries,
(10:42):
including Switzerland.
Um, this autumn.
So the, the, the program of, um,regulation is just brutal.
It's absolutely brutal.
And I'm very sorry.
The, the FDA, when we last spoketo them, they'd all just had a
letter of Elon Musk saying, whatare you doing every day?
(11:02):
And,
Joseph M. Schwab (11:03):
yeah.
Justin Cobb (11:03):
and we were speaking English and they were
speaking American.
And it was a very uncomfortableexperience.
I mean, I really, I've never hadthat experience before.
Very uncomfortable.
Joseph M. Schwab (11:11):
So, uh, let's talk a little bit about the, the
H1 itself, because like yousaid, you partnered with
Ceramtec and so the, theprosthesis itself, the bearing
surface is the Biolox delta,right?
Justin Cobb (11:24):
the, the device is monolithic Biolox Delta, which
I've been using actually.
I used, I was very happy withForte before Delta came along
and, but Delta now we've got, Ithink there's 13 or 14 years of
experience and, and tens ofmillions of people with Biolox
Delta in their bodies.
(11:44):
So it seems like it's quite asafe material.
Um, and so we felt verycomfortable, um, going to them.
So they.
The device, it's then coated inMedicoat.
Medicoat was set up in justoutside Zurich to coat, actually
it was set up by, um, Haki, um,Gruner to, to coat the furlong
(12:09):
ha coated, um, uh, hip back inthe eighties.
And his son Philip, runs thecompany now and they, they've
been coating Titan Tanium for avery long time and coating
directly onto green machinedceramic that is new, but it
seems to be, um, it seems to be,you know, if you do the testing,
(12:34):
you can rip it off, you canshear it off, and the forces
needed to, to take it off are abit greater.
Well, there's equivalent orderof magnitude to ripping off, uh,
plasma per titanium fromtitanium or cobo creme.
It's a very, very strong bond.
Um.
But adhe, the, if you, I don'twanna talk about adhesion
science.
(12:54):
It's very, very niche.
It's way outside.
Orthopedic surgeons pay grades,
Joseph M. Schwab (12:59):
But, um, suffice it to say you can,
you're putting these in withoutthe use of cement, correct?
Justin Cobb (13:04):
so both sides.
So I had good experience withCementless, um, metal and metal
resurfacing, and Paul Beaule in,in Ottawa, who's a real giant in
this world.
He, he's got, again, very goodexperience with the Conserve
plus Cementless.
Um, Tom Gross with, uh,cementless Recap in South
Carolina.
(13:25):
Um, KDA met in, in Gent has had,I think he's done all three of
those, um, cementless.
And it seems to, it seems asthough the Cementless feral
component, it's a safeconstruct.
And so we have the experiment ofplasma spray titanium on ceramic
on both sides.
So a single experiment, whereas.
(13:46):
We felt that going cemented.
That would be an experiment too.
No one had ever got a devicecement onto ceramic.
That would be a new one too.
Joseph M. Schwab (13:54):
Why ceramic as the bearing surface?
I mean, you have, I presumablythere are a number of different
options you could haveconsidered.
Why did you choose ceramic?
Justin Cobb (14:04):
yeah, so obviously initially, honestly the first
thing that came along was thecontour.
So in the old days, in fact inthe current resurfacings and
with total hips, two groin painis a thing in hip arthroplasty
and it's between sort of threeand five times as common.
Sorry, commoner in, inresurfacing arthroplasty.
(14:27):
Um, and that's partly, it lookslike it's mainly the acetabular
rim.
You know, it looks like ifsomeone sort of growing pain,
you probably didn't get thatanterior rim inside the pelvis
enough.
Um, and we.
Back in 2007, well done,actually one of my PhD students,
um, and I, we looked at thecontour and we realized it was
(14:50):
quite a mathematical contour.
And so we, we, we patented thatin 2007 and I wanted to do it
with metal on metal, but as wewere doing, it was obvious
metal, metal was going nowhere,and so a contour metal on metal
was never gonna run.
So we then looked the differentmaterials.
As I'm sure you know, the polymotion is in use in North
(15:13):
America right now.
There's an IDE going on in NorthAmerica, which is a metal on
highly cross think poly, um, butwhat we, in our preclinical
testing, um, it, one of thethings about the, the group of
people who want really benefitfrom resurfacing are the young,
very active men with cams, allof whom have quite shallow
(15:33):
sockets.
And the young, very active womenwho, some have got cams, but
quite a lot haven't.
They've just got a bit ofdysplasia, quite a shallow
socket and leaving.
So you have to have theopportunity to leave some
substantial amount of uncoveredbone uncovered prosthesis
laterally to give them the goodarticulation and that
(15:57):
unsupported polyethylene, um,the preclinical testing, it just
fails it.
So we unsupported, metal backed,it doesn't fail it, but without,
um.
Metal backing.
We couldn't get polyethylene toto, to succeed.
So we had to go to hard on hard.
And in Europe, I think in everycountry in Europe, ceramic and
(16:17):
ceramic is a well established,um, bearing couple.
It's only really in NorthAmerica that doesn't, doesn't
accept that as a regular thing.
Um, in Europe, um, we've all gotreally good experiences, I think
of, of, of c ceramic bearings.
And so we went to that and, andin fact the un unsupported, um,
(16:41):
rim, it's a really, you've gottahave the ability to have a cup
that is unsupported in mild oreven moderate dysplasia that is
not gonna fail.
Joseph M. Schwab (16:52):
So do you think the reason, um, the, the,
is the primary reason that thecups were sort of exposed
anteriorly or groin pain wasoccurring anteriorly more common
in resurfacings because of thematerial, because of the shape
of the device or because of thesize of acetabular prosthesis
(17:12):
relative to a more conventionaltotal hip or a combination of
those
Justin Cobb (17:16):
Combination.
Combination.
So, um, I wanted, I'll send youa last picture showing the, um,
uh, of an acetabular componentof a metal, metal one and our
contour.
And the fact is, if you haven'tgot a cutout for the oop pubic
recess anteriorly, where the Scomes and the ichi, it's much
(17:40):
more gradual recess posteriorly.
If you haven't got thosecutouts, you've gotta put the
socket a long way further in toavoid, avoid, um, conflict.
And we can, we can leave thecenter much more where it wants
to be with the contours.
Um, so, so I think it reallymakes a substantial difference
(18:03):
to the surgeon trying to get thesocket in the right place
because it doesn't have tooverhang except to give you back
your, your where whale scar was.
You've now got a lovely big, um,peninsula there, but you haven't
got overhang for sos um,anteriorly.
Joseph M. Schwab (18:19):
Interesting.
So you, you briefly mentionedindications and, and let's,
let's talk about this because,um, indications over time for
hip resurfacing kind of shranksubstantially, uh, from
everybody can get it to, youknow, maybe males with a larger
bone size and their, you know,who are very active in their,
(18:41):
you know, fifties to sixties,forties to sixties.
It's different depending on theliterature you look at.
But certainly over the last 20years, the relative indications
for a traditional hipresurfacing contracted.
From your perspective and withthe development of the H1, does
it address some of the reasonsfor those, uh, changes in
(19:02):
indications and what are your
Justin Cobb (19:04):
so so the, it, it wasn't so much the indication, I
think it was the, as the truthof the matter, the problem was
edge loading of the wear scar ina metal or metal bearing.
That was the problem.
That was the only problem.
And to get a, and I've gotseveral very, um, prominent
female athletes and dancers andso on who are 10 and 15 years
(19:26):
after every resurfacing, doingjust great.
But you had to get the socketorientated, right?
You didn't get it right.
They got, um, um, high Medlinelevels and Tom Gross has
published on this, and he is areal master of this.
Um.
So the indication in women isvery strong.
(19:46):
If there isn't acontraindication, the
contraindication of a, um, auniform thickness metal bearing
couple means you've just gotthis very small surface area on
the smaller sizes.
With ceramic, ceramic, the rulesare completely different with
literally, I think I don't, withmillions of ceramic and ceramic
bearings with decades in humans,the case report of edge loading
(20:11):
of runaway wear has yet to bepublished.
And because we all love badnews, you know, we all love bad
news.
If there was bad news, theceramic and ceramic haters would
be putting up pictures of edgeloading of runaway wear on every
talk they gave.
But it seems to be a, a, a amore, a much, much more benign
(20:31):
tribal environment.
Um, so the worry about edgeloading of runaway wear doesn't
seem to be there.
And so for women.
Um, resurfacing is a greatoption for women.
It really is.
It's fantastic.
And unlike the sporting, um, we,uh, athletic man, women live
(20:54):
forever.
Okay?
They're never gonna die.
And, and to cut large bits outof them, um, unnecessarily, it
seems like a big mistake.
So, so our indications areadequate bone mass.
And the one thing that gives methe heebie-jeebies is
(21:14):
bisphosphonates someone who'shad bisphosphonates
preoperatively.
I think that's a.
I, I don't that, that's adifficult, I, I think it's just
too scary for us right now.
Um, but if someone's got a, ifthey're a healthy adult, that
means that we know Wolf's lawcarries on working in your
(21:34):
nineties and hundreds.
You know, if you are active, youkeep your bones active.
So, so, um, in our trial we had70 as the upper age limit.
Um, and I, I had one, um, builtmuscular Californian man who
literally sent money trying toBri he was 72 trying to bribe
(21:57):
his way onto the study.
Um, and so since the trial, Imean, people in their seventies,
as you know, there are lots ofreally good people in their
seventies.
And to say to them, no, you'vegotta have your femoral head and
neck cut out and someone bang abig bit of metal into their fma,
well, you know, you don't haveto have that, I don't think.
Joseph M. Schwab (22:16):
I suppose how, how about things like, um,
certain types of pediatric hipdeformity.
So you said adequate bone stock,is that just dealing with
osteoporosis or things likeperthes, advanced Perthes and,
Justin Cobb (22:29):
So the planning, I mean the, the we've done a
really difficult per is isreally difficult.
It's really hard.
Um, of course it is.
And so there's some things thatare just too difficult and you
can't do very much withpeople's.
Um, you know, you can't do whatyou can do with an estro with
(22:49):
resurfacing, of course youcan't.
But I have, um, done correctiveosteotomies and resurfacing, um,
simultaneously with fractures ofthe proximal femur.
I think that's something you cando, um, and just resurface the
feral head.
Um, but I think in bad path, Imean, and bad av n too, of
(23:10):
course you can't use it forthose things.
Joseph M. Schwab (23:12):
So do you look at version of the femur?
Um, for instance, before you're,when you're planning for a, a
hip resurfacing, would youcorrect a femoral version?
Or obviously you're not gonna dothat through the prosthesis, um,
but or do you just prefer to putthem where they anatomically
came from?
Justin Cobb (23:29):
So it's a great question, and in, in really bad
DDH with huge, um, femoralinversion in my old days of
metal on metal, um, I, on acouple of occasions did a
rotational osteotomy of thefemur the same time as, um,
during the resurfacing.
I haven't seen, you know, it'sa, it's a real question, but I
(23:52):
just haven't seen that for awhile.
Um, and I, but I think the rulesare the same in all
arthroplasty.
You've got to give somebody abiomechanically sound, um,
reconstruction, which mayrequire corrective osteotomy,
Joseph M. Schwab (24:09):
I think, um, the, the kinematic alignment
total knee folks are challengingour conventional wisdom as to
what, uh, biomechanicalsoundness is.
And, uh, I, I, I find thatinteresting as well from a total
hip
Justin Cobb (24:21):
for the, from the femur, you know, the, I I hope
we're gonna publish quite soon,some more work on, on the, the
elasticity of the femur and, um,and the, the, the impact of e
femoral stem on that, on thebiomechanical properties of the
femur.
Um, and if you've, if you cansave the compression trabecula
(24:46):
from the car, car going up ontothe femoral head, if you can
save those, then your hip flexesare just driving straight up
them.
If you cut them off, they'vegotta go down into the.
Um, shaft to bond onto themetalwork and then go back up.
It's just, it's a tortuous routefor the forces to be delivered.
Joseph M. Schwab (25:07):
you've mentioned briefly your
detractors, uh, well, you saidsort of jokingly, you know, if,
if detractors were finding theseproblems, of course they'd be
bringing'em up online.
I.
I'm certain you must have runinto some detractors in during
this development period for somereason or another.
What are they saying and hastheir message changed over time
or has it gotten louder orquieter?
(25:28):
What would you say?
Justin Cobb (25:31):
um, I think I got, I've gotta be, um, gotta be
polite.
It's DA data.
You know, there are big hipgroups that publish huge amounts
of stuff that have neverpublished any outcome data.
Not not revision rates, butactually outcome.
(25:55):
And if you look at the Swedishregistry, and the Swedes have,
have done a pretty, a very goodjob of looking at how their
patient's doing, not justrevision rate, but everything
else in their registry.
Um, the, uh, cemented stem isn'tthat great, you know,
functionally in terms of outcomestudies.
(26:15):
They're not that great andcement less stems seem to be
better, but not as good asresurfacings in functional
terms.
Now, of course, there'sselection bias and all that.
Of course there is, but no one'sever done the other way around.
No one's ever shown, um, thatthe, the resurfacings do really
(26:37):
badly, um, functionally.
Um, and so to say, I insist oncutting out your femoral head
and, and fossilizing the insideof your proximal femur.
So the big arguments in Britain,honestly, it's about cemented
stems.
Can you believe that?
Um, it's amazing.
(26:57):
They really are devoted to that.
Joseph M. Schwab (27:00):
Is there, um, do you have any thoughts or
plans on, um, uh, turning the H1into, uh, sort of a smart
implant or something that hassome built in sensors so you can
understand, um, maybe a littlebit more in depth what the
interface with the bone is like,what the load transfers are
like, or any other, um, uh, anyother changes to the
Justin Cobb (27:24):
So, I mean, it's a really interesting, it's a
really interesting question.
I, I feel the, um, because youare just putting a coating on
the, on that femoral head, um.
It behaves, it behaves very likea normal femur.
It really does.
Um, and I think it's a, I thinkthe, I mean the thought of going
(27:47):
through ethics and the, all thedevelopment pathway to get the
strain gauges into something inthe femoral head, I'm not up for
that yet.
I think when we've got, youknow, we've only got seven and a
half year results so
Joseph M. Schwab (28:01):
Yeah.
Justin Cobb (28:01):
and
Joseph M. Schwab (28:01):
Yeah.
Justin Cobb (28:02):
nobody thinks that's long term.
I think if we absolutely knowwhat the 10 and 15 year results
are like, then I wouldn't feelbad about asking someone to do
that.
But for the moment, I think we,we, I wouldn't ask someone to
have that done.
Joseph M. Schwab (28:19):
Thank you for joining me for this episode of
the AHF Podcast.
Be sure to join me next week forpart two of my conversation with
Professor Justin Cobb.
Please take a moment to like andsubscribe.
You'd be helping us find morepeople just like you to share
this content with.
And as a subscriber, you canalways drop an idea for a topic
(28:41):
or any feedback you like in thecomments below.
You can find the AHF podcast onApple Podcasts, Spotify, or in
any of your favorite podcastapps, as well as in video form
on YouTube slash at anterior hipfoundation, all one word.
New episodes of the AHF Podcastcome out on Fridays.
(29:05):
I'm your host, Joe Schwab,reminding you to keep those hips
happy and healthy.
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