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A member of my Hip Talk Discussion Group asked why it took surgeons so long
to learn how important the angle of the acetabular cup angle is during hip
resurfacing surgery. Incorrect placement of the acetabular cup has caused many
failures of hip resurfacing resulting in revisions of hip resurfacing to total
hip replacements.
My answer to that questions of why it takes so long to learn if a hip device
and/or surgical technique is successful is if anyone has worked in the
engineering or design field, they will realize that usually the original design
of a product or machine is never what the final design turns out to be. We are
not machines that can determine perfect designs for anything. There are always
unknowns. If you think about many things in our lives, they are always under
constant change and updates. Car models are often changing, TVs are changing,
cell phones, computers, etc. are constantly in change. Software for computers
are always updating and changing. Athletes are always changing techniques to
improve their skills. Musicians are always practicing to improve their skills.
Medicine and joint replacement is not any different. Engineers are trying to
design a device to replace a human joint while doctors are trying to place that
foreign object in our bodies to act as the original equipment. This is not an
easy task. There have been thousands of designs of hip devices over the years.
The metals or plastics continue to change, the metallurgy changes, and the
designs of the components change. There is nothing static about designs, they
are constantly changing.
I learned from the hip resurfacing conferences I attended, that it takes time
for doctors to learn how the devices are actually functioning in patients.
Typically it takes about three to four years for them to start to see trends
about how the device has acted and how the bone growth has attached to the
components. It takes time for the results to become statistics. So with any
device, the wait period is long and often by then, there has been a change in
the device design. As a result, there are few devices of the same design left
after a few years to compare results.
It is very difficult tracking the new devices and their results right after
their implant since it takes time for the bone to attach to the components. Many
of the top experienced surgeons were placing the actabular cups at a good angle
early on. They knew instinctively that the acetabular cup should be in a certain
position to work well. I have always said and heard surgeons say that surgical
skill is more than a skill or learned process, it is also an art. It is similar
to the great athletes that instinctively know what to do. They do learn and
practice, but have a God-given skill that places them way above many other
athletes. The same is true with the really top surgeons. If you think about
sports or activities you are personally really good at, you are not looking at
the educational videos or books to learn how to throw a ball, play an instrument
or type on a computer. Those with really good skills are able to do it almost
without thinking. That's is the way it is with the top surgeons. They had an
instinct about how things should work and were very successful. McMinn of the UK
is doing that all the time as he develops devices. Many of the other top
surgeons have helped develop hip devices and many of the surgical instruments to
help place hip devices. A recent example of one is with Dr. Kusuma in Columbus.
http://www.surfacehippy.info/observinglivesurgery.php He wanted a better way
to insure his placement of a BHR was correct. He developed a template system
which no other surgeon had done before. Smith & Nephew are thinking of having
him teach it to new surgeons.
There is a great deal of constant change with any hip device or any man made
mechanical device. Designs keep changing and hopefully for the better. Skills
and instruments to place joint devices keep changing and hopefully for the
better. It is very complex and just takes time to develop excellent devices and
how to place them exactly. The orthopedic surgeons keep track of their series of
hip resurfacings and the National Directories
http://www.surfacehippy.info/nationalregistries.php keep track of hip
resurfacing patients. It takes time for all the statistics and results to
accumulate and become tools to help learn about a hip device and a specific
surgical technique.
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