Thursday, March 9, 2017

tailor made knee replacement. oxford unicompartmental knee replacement

Long gone is the era when we used to become homebound and depressed after end stage arthritis hit our knee.

We have become active and sporty in modern India. Our life expectancy has improved.
Some of us have become too busy in our day to day life. Hectic or sedentary? Difficult to say but surely lack of exercise and poor nutrition comes with it's penalty. 

Wear and tear of joints aka osteoarthritis has become very common as a result of above. We are living longer, some of us are getting injuries because of overactivity and some succumbing to lifestyle disease.

Knee joints are most commonly affected by osteoarthritis. why is that?
we humans enjoy an erect posture unlike most other animals. Our weightbearing knees let us enjoy all those sports and activities all our life but take the toll eventually.
They start wearing out.

interestingly the knee follows a pattern of wear and tear. Knee can be roughly divided in three compartments. inner, outer and knee cap

Most of us especially Indians have a slight bow in our shinbones (tibia) This causes more loading of the knee joint on the inner aspect  compared to outer aspect.
As the knee wears out more on the inner aspect the bow in the legs increases making us bowlegged.
We often see elderly people with bow legs. They have an advanced osteoarthritis of the knees which has caused the legs to bow because of asymmetrical wear.

Anyway, we doctors have always teamed up with our engineer friends to find solutions for worn out knees. Over last many decades we have been able to give people pain free knees to enjoy life.

When the arthritis starts we can advice various activity modifications and exercises. There are supplements to improve joint lubrication and keyhole surgery can tidy up the joint to make it last a bit longer.

However when the joint shows advanced arthritis these modalities cease to help.
That is when advanced engineering comes to our rescue.

Knee replacement design was pioneered in England and USA. Dr Insall played a critical role in defining the modern knee replacement.

Knee replacement aims at restoring the normal painfree functioning of the knee joint by replacing the worn out surface.
All three compartments are replaced.
There are three main components. A cap which covers lower end of thigh bone.
A base plate which replaces the top of the shin bone. A knee cap undersurface.
These components are fixed to the bone using an acrylic polymer which we cann bone cement.
Between these components is a long lasting bearing.
This is known as a total knee replacement popularly called a TKR.
In the last fifty years so many things have evolved.
we have understood the anatomy and geometry of the knee mush better. That has resulted in more anatomic designs of the prosthetic knees.
We have understood the dynamics of knee motion and the way we walk. This input has resulted in more natural feeling knee replacements.

The materials are evolving every decade.
We started with standard stainless steel alloys and we thought that's the best.
Then came cobalt-chrome, titanium alloys making our joints lighter and longer lasting.
Use of ceramics have increased the longevity further. I hope we have a knee which "never wears out" soon.

The fixation of the prosthesis to the bone has become more natural by use of various types of coatings like tantalum trabecular metal and hydroxyapatite.

The tools to perform surgery used to be precision engineered mechanical guides. We used to be very proud.

But computer navigation made these lovely tools a history.

Customized preplanned patient specific knee replacements made computers look primitive. Now all of this will be surpassed by use of orthopaedic robots.

Surgical techinique and training not only evolved by technology but modern surgical handicraft became minimally invasive.
Patients experience much less pain, they walk home quicker and they return to active life much sooner.

Mr Taylor came to me.
Keen golfer and sportsman.
About my age. instantly likeable person.

His knees were wearing out. Typical Indian mild bowlegs.
Wearing out only on the inner side.
He wanted to walk, cycle and golf.
He wished to lead active working life.
I examined him, did his xrays and scans.
Just the inner/ medial compartment worn out.
Outer compartment, kneecap, ligaments were in a pristine condition.

It was a long counselling session.
I offered him a very special solution.
Best of modern technology and surgical precision.

I decided to just replace the worn out medial compartment.
This is known as a "unicompartmental knee replacement"
Its also called "microplasty"

This very special technique was developed and perfected in Oxford England over last couple of decades.
It involves a delicate fine tuning of the worn out inner compartment by just removing precisely only the worn area.
Rest of the knee which is normal is preserved in its normal anatomoical functionality.

This is like a hybrid engine we see in high end cars today.

two different mechanisms married to each other functioning in unison for a great long term future.

Mr Taylor agreed to let me give him "tailor made" knees.

Because he was a man in a hurry with lots of commitments in a short span, I took another unusual decision in his case.
I operated on both his knees in a single sitting.
Normally I would do unicompartmental arthroplasty one knee at a time to allow a leisurely recovery time.

In his case I did bilateral single sitting unicompartmental arthroplasty. I believe a first one in Maharashtra.

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