Why Hip Resurfacing?

By Vicky Marlow

Hip Resurfacing is a bone preserving procedure that is a more conservative approach to hip surgery than the conventional Total Hip Replacement (THR). It gets rid of your hip pain but allows you to return to a full active lifestyle with no limitations.

As many medical sites will explain, (as this one does http://www.mcminncentre.co.uk/thr_today.htm#str ) one of the differences between resurfacing and a Total Hip Replacement is the amount of bone that is preserved or removed. With resurfacing your bone is preserved. Opposed to a THR, where they place a stem down your thigh and you can lose approximately 30% - 45% of your proximal femur.

Video that explains the difference between a Total Hip Replacement and a BHR (Birmingham Hip Resurfacing)

Hip Resurfacing, Alternative to Total Hip Replacement
Here is a great interactive video from Smith & Nephew the manufacturers of the BHR or Birmingham Hip Resurfacing device

Click here for Interactive video

In more detail regarding the BHR device
Part 1
Part 2

With Hip Resurfacing, they just shave off a little from the top of your femur and place a metal cap on it instead of cutting off the femoral head with a power saw the way they do with a Total Hip Replacement.  On the hip socket side or acetabulum, they place a metal cup which is the same for both Total Hip Replacement and Hip Resurfacing.

Here is a link that shows the difference in loss of bone between the two procedures. (Courtesy of Dr. Koen De Smet)

This is the part that stands out to me on a Total Hip Replacement (from one of the above mentioned websites): “The surgeon begins by making an incision on the side of the thigh to allow access to the hip joint. Several different approaches can be used to make the incision. The choice is usually based on the surgeon's training and preferences. Once the hip joint is entered, the surgeon dislocates the femoral head from the acetabulum. Then the femoral head is removed by cutting through the femoral neck with a power saw. To begin replacing the femur, special rasps (filing tools) are used to shape the hollow femur to the exact shape of the metal stem of the femoral component. Once the size and shape are satisfactory, the stem is inserted into the femoral canal.”

To me, it is like the difference between pulling a tooth and getting a complete root canal (Total Hip Replacement) or crowning a tooth (resurfacing).

Resurfacing allows a full return to all activities, including running. Many patients have even finished an Ironman since their surgeries. Yoga, martial arts, skiing, surfing, the possibilities are endless. Just take a look at some of the featured athletes on this site.

I realize some newer Total Hip Replacement devices also allow patients to return to most activities now, but there is really no long term data on the newer Total Hip Replacement devices that claim “no limitations” to really know what the long term effects of that will be (see Wolf’s Law below). This is because no matter what a Total Hip Replacement is made of, it still has the long metal stem and the improper loading of the hip and stress shielding. Most doctors will tell THR patients to NEVER run again, no basketball or any heavy impact sports, whereas this is not the case with resurfacing and the right surgeon.

There is now over 11+ years of history on the BHR device (see below), as a matter of fact the first protocol was implanted in a gal named Katie in 1991 and it is still going strong and she has had two healthy children since her resurfacing. Her children are now 9 and 14 years old.

The two main reasons you want to try to get a resurface first before a Total Hip Replacement if possible besides preserving your bone, is due to stress shielding, (Wolf's Law) which again, I will explain at the end of this, and also due to revision surgery. If you choose to remain active with a THR, you risk revision surgery which takes away more bone each time. Take a look at this animation video that shows you what they do to revise a THR .

With a hip resurfacing, IF you ever need it revised, it is like starting out with your first Total Hip Replacement.

Here is an explanation of Wolf's Law, remember, no matter what material is used with a Total Hip Replacement device, it still has the long stem.

"... Wolffe's Law of Bone, which is that bone is formed and retained along the lines of stress in that bone. Another way of putting it is: "Form follows function." Look at the trabecular pattern in a calcaneus or a proximal femur—it's easy to see where the lines of stress are here, because that's where the trabeculae are. Another way to express this rule is: "Use it or lose it." ..." and " ...What does this have to do with patients with prosthetic joints? Well, in an ideal world, a prosthetic joint component would carry stress and distribute it to the underlying bone in a manner identical to the original bone. Alas, this does not happen in real life. Prosthetic components react to stresses a lot differently than the original bone that they replaced, and tend to distribute it to the remaining bone much differently. For example, in a hip prosthesis, much of the load applied to the femoral component tends to be transmitted to the bone near its distal tip. The bone near the proximal part of the component tends to have less force transmitted through to it. What happens to the native bone that is now no longer receiving its usual loading? Bone loss occurs here. This phenomenon is called "stress shielding". Since one can get quite a bit of stress shielding around a prosthesis, it's no mystery why one sees progressive bone loss around prosthetic components over the years on follow-up radiographs.... "

The prosthesis referred to is the total hip replacement, not a resurfacing that loads the weight onto the femoral head, as the original issue joint does.

From http://medical-dictionary.thefreedictionary.com/

stress shielding
n. Osteopenia occurring in bone as the result of removal of normal stress from the bone by an implant.

osteopenia /os•teo•pe•nia/ (os?te-o-pe´ne-ah)

  1. reduced bone mass due to a decrease in the rate of osteoid synthesis to a level insufficient to compensate for normal bone lysis.
  2. any decrease in bone mass below the normal."

With resurfacing the load on the hip is more like your natural hip. Again, it is similar to crowning a tooth instead of pulling it and doing a root canal. There is a lot of info available, feel free to email me and I will be happy to answer any questions. I hope this information is of value.

Click to link to BHR 10 years of Data