This is a transcript of a
Live Chat in the Surface Hippy Chat Room with Dr. Gross on September 30,
[Dr. Gross] 6:59 pm: Good evening
7:00 pm: Dr. Gross is from SC and has done over 1500 hip
[Dr. Gross] 7:00 pm: Thank you, I
appreciate you having me
 7:01 pm: Dr Gross – I’m a 51-yr old
female who runs 2-3 times a week – just a couple miles each time. How much do
you think running will impact on the useful life of a BHR?
[Dr. Gross] 7:02 pm: Its
hard to say probably it will last at least 8 years if you use good running shoes
but no one knows for sure
[linejudge42] 7:01 pm: Hi Dr. Gross, in reading some literature on
the Uncemented Biomet Recap, it appears that the cap prosthesis is “thinner” than
other vendor “hybrid” versions. Considering this, theoretically, I would think
that if at some point the uncemented cap came lose, that a revision would not
necessarily require a THR. I would think there would be enough bone on the
femoral head where a revision to another resurfacing prosthesis could be used?
What are your thoughts?
[Dr. Gross] 7:03 pm: Its unlikely a revision of a resurfacing
would be possible without doing a total hip
 7:02 pm: how can the
cementless withstand impacts as well as cemented versions?
[Dr. Gross] 7:04 pm:
The same way a cememtless cup can withstand impacts currently. It is likely that
uncemented fixation can within stand impacts than cemented, this is the case
with other implants.
7:03 pm: You say perhaps 8 years if I continue running – what’s your guess for
useful life if I don’t run.
[Dr. Gross] 7:04 pm: Pure
speculation since we only have 8 to 10 year results at this
 7:05 pm: without impacts like jogging or such, is long term
longevity to be hoped for?
[Dr. Gross] 7:08
pm: At this point 95% remain successful at 8 years. It is not known how impact
exercises will affect this durability. Cement is likely to last longer without
repetitive impact. Repetitive impact will not wear out the bearing
[barryc] 7:06 pm: Dr. Gross – From a surgeons perspective what are
the key factors that help determine if a cemented or cementless implant is most
appropriate and are there any contraindications for the cementless
[Dr. Gross] 7:09
pm: My preference is to use only uncemented, so far I have not found any cases
where an uncemented component would not be preferable to cement.
 7:06 pm: A lady could not be here,
but asked me your thoughts on this about metal ions. She is trying to find out
what the normal numbers would be. My chromium plasma levels taken at 11 months
are 499.98 nmol/l, which I believe converts to 26ug/l . I am definitely way above average. So my question:
Does anyone know what the safe levels of chromium and cobalt ions are? In nmol/l
Gross] 7:11 pm: No one knows what safe levels are. These are normal elements in
our body. They are elevated after placing metal implants. There is no value to
measuring and following levels at this point.
[firstname.lastname@example.org] 7:07 pm: what
are your thoughts on daily exercise (elliptical, treadmill) I am 2 years post
bi-lateral BHR and 41 years old
[Dr. Gross] 7:12 pm: At 2 years virtually all exercise is good
except possibly extreme repetitive impact sports such as marathon running. No
one knows for sure.
[monona] 7:12 pm: How does the Biomet implant compare with the
Birmingham prosthesis in patients with dysplasia?
[Dr. Gross] 7:15 pm: Mild dysplasia can be
done equally with any company’s component if there are severe acetablular
defects the specialized dysplasia cup made by Birmingham and Corin are helpful.
I would make a custom component with Biomet to handle the more severe
 7:12 pm: a famous retired tennis player was on the courts 6
weeks after minimal invasive large ball total hip. As I understand it recovery
of full function is a bit rougher and longer with resurfacing? you perform both
[Dr. Gross] 7:17
pm: The recovery is identical. The return to tennis this early is risky with
either type of procedure. I would recommend waiting 6 months to return to
vigorous activity. Yes, I perform both.
[Marcia] 7:12 pm: Hi, Dr. Gross! As one of
your uncemented patients from January of this year, I was really pleased to see
the results of your study on uncemented thus far.
pm: Thanks – this has been an awesome device so far! Just minor muscular aches
with over exertion.
Gross] 7:17 pm: Marcia, glad you are doing well.
[DBall] 7:12 pm: I know you are really concentrating on your
uncemented device right now but do you have any plans to develop something
similar to the BMHR that would use the Biomet Cup?
[Dr. Gross] 7:19 pm: Biomet has just released
a tri-spiked cup for supplemental fixation for moderate deficiencies. I have
used some of these, I use custom components for severe defects, eventually I
hope that these will be available off the shelf.
[barryc] 7:12 pm: Are you
aware of any metal ion studies on the ion levels produced by the leading implant
manufacturers and if so which implant, in your view, has the advantage here. As
a follow up, does Biomet have or are they working toward a lower ion producing
implant? If a more advanced devise is on the horizon and if so, is there a time
frame you can share?
[Dr. Gross] 7:21 pm: I have seen no comparison studies on ion
levels, Wright has an implant that uses a forged head and cast cup combination
which they claim produces less wear and ions. In the future diamond bearing may
be possible but research is in the very early stages.
pm: what options do you see on the horizon when (and if) a BHR wears out. Is a
THR the only option in this case?
[Dr. Gross] 7:21 pm: THR replacing only the femoral side is the
 7:21 pm: How about ceramic for hip resurfacing?
[Dr. Gross] 7:23 pm: I believe there is one device being used in
Germany currently but I have seen no results. It is very difficult to apply a
bone ingrowth surface to ceramic. Also ceramic is brittle and may fracture with
running activities. I would rather have cobalt and chrome ions and an implant
that does not fracture.
[DBall] 7:22 pm: The reason I asked
you about your plans for a future BMHR like device is because I am concerned
about revision(s). Is there anything you see in the future that will a better
option for revision from resurfacing than a THR?
7:26 pm: Not really. There is a very short track record for the Birmingham mid
head resection device. Also there are short mini stemmed total hip implants. But
the area of ingrowth is virtually the same as for a standard total
 7:24 pm: What amount
and type of activity is helpful in the initial week after surgery? I know
stretching is important, but would walking around the house with an aide
(walker, cane) in the initial week (as long as you can stand the pain) be a good
thing to do?
[Dr. Gross] 7:27 pm: Walking is a great
exercise for the hip, you should gradually be able to walk longer distances
outside, I would be very careful with stretching, hip range of motion will
return to normal with or without stretching.
 7:25 pm: will you perform
resurfacing under general anesthesia?
Gross] 7:28 pm: I will and I think it is equally as safe as a spinal anesthetic.
My preference is spinal because we can achieve better post operative pain
control in most cases.
[Jon] 7:29 pm: If I have
“Coxa valga” (so say a few people who have seen my x-rays)–is there any way to
“correct” this with resurfacing, or at least improve the angle so that the main
hip stabilizers are working more efficiently?
[Dr. Gross] 7:32 pm: No, it can not be
changed with resurfacing but it does not need to be changed. If you have an
arthritic dysplastic hip resurfacing will relieve the pain and allow you to
regain normal strength. Having a valgus neck may decrease your risk of femoral
neck fracture with this procedure. You can correct the valgus with a total hip
but you are taking more bone that could be preserved. Not a good trade
[monona] 7:31 pm: I was a competitive ballroom dancer prior to
developing arthritis. My range of movement is severely limited and of course
there’s a lot of pain. How soon after resurfacing can one return to competitive
dancing which places so much torque on the hip with movements such as
[Dr. Gross] 7:34 pm: You may return to competitive dancing
gradually at 6 months. At that point bone ingrowth should be 90% into your
components. The femoral neck has recovered from the surgery and will not
fracture and your hip ligaments have healed to approximately 80% of their normal
strength. At one year all of these are up to 100%. If you try to return too
early, you have a higher risk of complications.
 7:32 pm: how often do you plan on a
resurfacing and have to change to a total hip instead?
7:35 pm: I have only done this twice in 1500 cases, both cases had
osteonecrosis. I under estimated the extent of dead bone in the femoral
7:35 pm: What are your thoughts on the sitting angle for people with
resurfacings. People with THR’s are instructed to be sure their butts are higher
than their knees for quite a long time. Is that true of resurfacings? How long
before it’s OK to bend at the waist?
[Dr. Gross] 7:39 pm: For total hip it depends on the bearing size.
If the jumbo (resurfacing sized) bearing is used, much fewer restrictions are
required because the hip is intrinsically stable. With both operations we do cut
the hip capsule and this takes 6 to 12 months to heal. This is a secondary
stabilizer of the hip. Extreme range of motion before full healing can lead to
dislocation. You can sit normally right after surgery with a large bearing,
restrictions for more extreme motion can then safely be
gradually be lifted over the next 6 months. Small
bearing total hips always require some restrictions.
 7:38 pm: are bone cysts the same as necrosis?
[Dr. Gross] 7:40 pm: Bone cysts are holes
in the bone caused by arthritis, necrosis is a completely different disease
[email@example.com] 7:38 pm: Is a revision to a BHR a
more difficult surgery than the initial resurfacing. I had both hips done at the
same time. Would you do 2 revisions simultaneously?
[Dr. Gross] 7:42 pm: Revision of a HSR to
a THR is easier than performing a primary total hip replacement if it is the
femoral side that is being revised. Both can be done
[gabulldog] 7:39 pm: Hey Dr. Gross. You
performed my resurfacing surgery in May. I’m doing great. I’m just struggling
with the thought of going back to running (which I would love to do). I’m 35 and
I would like for this device to last a very long time. You told me during my
first visit that I will eventually have to have my right hip resurfaced. Should
I definitely consider light jogging or should I stick to the elliptical and
walking so I don’t wear the right one down any faster?
[Dr. Gross] 7:43 pm: Running will
probably make your right hip wear out sooner but you know we can fix it.
Elliptical and walking will not be as hard on your hip.
pm: How soon after resurfacing can one start stretching to regain rom? Do you
recommend any type of physical therapy?
Gross] 7:45 pm: You may start stretching at 6 weeks but no extreme flexion
exercises for at least 6 months. Physical therapy is not required after a
posterior approach, the muscles recover quickly with walking and a simple home
7:40 pm: I believe there were only two or three failures of the uncemented thus
far and were due to femoral neck fracture and no greater percentage than
cemented – were those early in the recovery period? I think that this is still
my biggest concern at this point (8 months out). Also, when I come back for my
checkup in January, will you be able to see how much bone ingrowth I have from
the stem and how well does that translate to ingrowth in the
[Dr. Gross] 7:47 pm: I have had
3 out of 320 femoral neck fractures in the uncemented series, they all occurred
before 6 months. This is the same as my cemented experience. There are case
reports of later fractures but they are rare. I have had no femoral neck
fractures after 6 months.
[Dr. Gross] 7:49 pm: You
can’t actually see ingrowth because the porous coating is under the metal. One
infers that bone ingrowth has occurred if the implant remains stable on x-ray for
 7:49 pm: So on the 4th day after
surgery, when people tell me to “sit down, get off your feet, your doing too
much!”, I can tell them “YOU’RE WRONG – THIS IS GOOD!!”?
[Dr. Gross] 7:54 pm: You should be
up out of bed, walking around in your house, sitting in a chair most of the day.
Walking outside for one to two blocks a day is a good idea. You can gradually
progress your walking from there. You should also ice and
[gabulldog] 7:53 pm: An earlier question referred to some of your
research on the uncemented device. Have you posted this on your website? If not,
where can we find it?
[Dr. Gross] 7:55 pm: Yes, it is on my website (www.grossortho.com)
under “current topics”.
[linejudge42] 7:53 pm: Dr.
Gross, at the start of the chat, you mentioned an HR may only last 8 years for a
runner? Is you answer just based on current data? It was my understanding that
once healed, there were no physical limitations. An 8 year expectancy for
runners would seem to put some real limitations on physical activity. Or do you
really feel it could last 20 – 30 years, but you just don’t have the data to
back it up.
[Dr. Gross] 7:57 pm: You
are correct, there is no data that tells us whether running will make your
implant fail sooner, there is no data to tell us about survivorship of HSR after
8 years, only an educated guess.
 7:58 pm: When
someone has the unfortunate experience of a femoral neck fracture, is it usually
a sudden thing that the patient knows immediately due to the
[Dr. Gross] 7:59 pm: Yes it is usually sudden and very painful but
we have had a few cases where a stress fracture develops gradually over a week
 7:59 pm: Dr. Gross. Thank You very much for taking time to
answer everyone’s questions. We all learned a lot.
[Dr. Gross] 8:00 pm: Thank you