Post-operative exercise – the BoneSmart view

[Roy Gardiner]

Post-operative exercise – the BoneSmart view​

Post-op exercises target the gaining (or regaining) of

- Mobility and range of motion (ROM)*, during and after healing
- Strength and fitness, after healing is complete

The exercises required for these are quite different, and it is essential that strength and fitness training isn't done until healing is complete. This is because TKR seriously damages the soft tissues (ligaments, tendons and muscles) around the knee and attempting strenuous exercise too soon will worsen this damage and slow or stop or even reverse the healing process. Compare it to running on a broken leg! (Note: the new artificial joint itself is not at risk of damage, it's hugely strong).

*There are two components to ROM; ‘flexion’ and ‘extension’. Flexion is the measure of how much you can bend your knee, in the range zero to about one hundred and fifty degrees. Extension is how much you can straighten, also measured in degrees. A dead straight leg is zero degrees; one that can go beyond straight to bend back slightly (this is good) is measured in minus numbers, e.g. -2 means two degrees of backwards bend.

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Exercise characteristics

Mobility and range of motion

There are many such exercises, but they all have common characteristics

- There is little force through the knee, movement is often passive with no force at all
- They do not hurt, they are just uncomfortable (no pain, more gain!)
- They do not raise the heart rate or cause you to breathe heavily
- They are of very short duration, typically 30 seconds or so, repeated often
- It is not necessary to have a therapist or trainer to do them
- So, they are not scary, difficult or especially challenging; they are simple and straightforward.

To read more, "Stretching" by Bob Anderson, ISBN 0 7207 1351 X

Training

Strength and training exercises are almost the opposite in every way

- They put force through your knee
- They hurt
- They raise the heart and breathing rate
- They can last for minutes or even hours
- They are a real challenge

In the early parts of recovery one should only do mobility exercises, not strength or fitness training.

An example of mobility exercise vs. training on the same piece of equipment

Let’s consider the use of a stationary bicycle (aka training bike or turbotrainer).

Mobility: The machine is set to zero resistance. If you cannot make a full rotation of the pedals, you set the saddle as high as you possibly can then just rock the legs backwards and forwards to the point of serious discomfort but not pain in the TKR knee. Once you can make a full rotation, you set the saddle at the lowest level where one rotation can be achieved (again with discomfort) and pedal 20-30 revolutions only on zero resistance. These exercises are repeated many times a day. You don't need 10 minutes on a bike to gain mobility; 2 mins, zero resistance, is enough.

Training: You pedal against resistance. The saddle is set at normal height for you. You pedal at a level so that you are puffing a bit and your heart rate is elevated. The exercise continues for ten minutes or until you are too tired to carry on.

It is essential not to do training type exercise in the first stages of recovery, we recommend a minimum of at least for a month after your TKR or longer until your knee isn't swollen or painful.

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Some exercise examples

We recommend the ROM exercises for the early stages, the strength exercises later. Neither ROM nor strength exercises should be allowed to cause pain in your knee. There are further ROM, Extension and Quad exercises here.