Question

[Barbara]

This is a question I'm sure only a woman would ask. Does anyone know what the BHR device weighs?
I've lost approx 20lbs since surgery and though I felt that I had lost weight I thought it probably wouldn't be much since the metal devices would maybe add some weight. I have blamed the fact that I had taken tylenol or was wearing earrings etc for my weight in the past so am hoping that I can blame my new hip joints then I can get away with being a chocoholic!
My husband says they wont weigh much at all but I'm ignoring him.

Barbara

[Mudpro]

I had the opportunity to handle both the BHR components and some THR components in a joint replacement class I participated in before surgery.  I don't know the actual weight, but it is made from titanium and high cobalt chromium, in other words it weights more than it would appear, but it still doesn't weight very much, far less than one pound.

Sorry, but you can't blame that extra piece of cheesecake on the hip...  ;D

The other thing I did notice when handeling the pieces, is how smoothly they glide when mated up, almost like they were lubricated.  These are VERY well made components.

[Todd]

I'm telling everyone that the components weigh about 15 lbs.  That way I still have an excuse.  This will come in very handy.  ;D

[Barbara]

Sorry Bill, I like Todds answer better. Thats exactly what I'm thinking ;D

[wayne-0]

I held an ASR device at my Doc's office and was amazed at heavy it really was. The first thing that came to mind was this thing is exactly like a trailer hitch/ball. I don't know how heavy it is but it seemed similar to a 2" trailer ball. So you have the go ahead for the consumpation of all chocalate products.

Wayne

[Pat Walter]

HI Mudpro

I just wanted to remind everyone that the BHR and other hip resurfacing devices are not made from titanium.  The hip resurfacing device is really a metal bearing made of  High Carbon Cobalt-Chromium-Molybdenum alloys. I am not sure if all the devices have Molybdenum in them. MOM THRs are also the same metal.  Other types of THRs are made from titanium.  I just wanted to set the record straight.

Titanium usually does not metal allergy issues or high metal ions.  It is the Cobalt Chromium that causes the high metal ions due to the wear in period or from hip devices placed incorrectly.

Pat

[Barbara]

Thanks Wayne, I'll heed your advice. Chocolate here I come!
Barbara

[dvander]

Pat, you burst our bubble!!  I thought it was so cool to say I had titanium in the hip.  I am not sure I can pronounce and get this:  High Carbon Cobalt-Chromium-Molybdenum alloys.  By the time I get it out of my mouth, the listener will be thinking about his old high school science class.......

Any true weight for the BHR?  It seems the weight is between 1 - 5 pounds.  It would be great to know if it is closer to one than five.

Dwight V

[Pat Walter]

Hi Dwight and everyone

Here are a few nice articles about the metal composition of the hip resurfacing devices in relation to metal ions.  At least you can read about the make up of the device here.

http://www.grossortho.com/forms/MetalIonWhitePaper.pdf with a number of other articles here  http://www.surfacehippy.info/metalioninformation.php

I think the devices weigh about 1 pound give or take since some people have small devices while other people require very large devices.  You can easily hold one in your hand without it feeling like a large can of soup. 

I also am not sure if all of the hip devices have Molybdenum as part of their metal content.  I have read that in some places and not others.

Pat

[stevel]

I calculate the weight to be approximately 1 pound.  I assumed the following:  The device is approximately a hollow semi-sphere; the average diameter is approximately 50 mm; the average thickness of the ball and socket is approximately 5 mm; the shaft length is about 50 mm and the diameter is about 5 mm;  equal parts chromium and cobalt which have a density of 7.19 g/cm3 and 8.90 g/cm3 respectively.

[dvander]

Steve,

You definitely sent me back to science class.  Wow!  That is a great explanation.  Thanks for the post.

Now can you estimate the weight of a 16 pound bowling ball on the planet Mercury?

Dwight V

[stevel]

Dwight,

A 16 pound bowling ball will weigh about 6 pounds on Mercury as the surface gravity is 0.38 of Earth's gravity.  Unfortunately I believe the bowling ball will melt (I don't know what the melting point of a bowling ball is - but it is plastic or polymer based) as the average surface temperature on Mercury is 334 degrees Fahrenheit whereas on Earth the average surface air temperature is 59 degrees Fahrenheit.

Side Joke:  I asked Dr. Su if I could run after 6 months post-op.  He replied:  "You are an Engineer, you figure it out."  In other words he doesn't promote running on hard surfaces as it may shorten the life of the BHR but he doesn't forbid it either.  OK if I run, I'll run on beach sand.

[dvander]

Steve,

Your posts brighten my day!  When I asked Dr. Jinnah when I could run my next marathon, I got a blank stare.  So I threw in, when I could pick up my bicycle again.  That was an affirmative three months post op.

I long to jog on any soft surface available, but not for a few months yet.

Again, Pat, thanks for the great site to keep in touch with surface hippys.

Dwight V

[DirkV]

As a surface hippy who rides a bicycle for hobby/recreation, this is an interesting thread. In cycling, perhaps the most important performance measurement is weight/power ratio. I asked my surgeon, and he gave an off-the-cuff answer of 2 lbs additional weight for the prosthetic, or a total of 4 lbs. for a bilateral. Of course, it's not just the weight of the device, but the net after shaving off bone to set the device. I guess I'll just have to save $ for some equipment upgrades to offset my metal hips  :)

-Dirk

[stevel]

Check out the photo of Dr. Su and I, under the hip stories section, Dr. Su on this website.  My story is at the top of the page.  Dr. Su is holding a hip resurfacing device between his thumb and fingers.  This indicates a weight of about 1 pound rather than 5 pounds unless he has vice grip fingers and thumbs.

[dw]

I asked prior to surgery (BHR) and I was told around 2 pounds total for the device...FWIW.

2 polished surfaces should glide very nicely over one another!

Dave