This Primer runs through the practical things you need to take care of before your knee surgery
Page updated August 2023 by Dr Sheila Strover (Clinical Editor)
- Anaesthetic options that may affect your immediate mobility after surgery
- Things to buy or hire before the big day
- Are you well prepared to manage Walking Aids?
- Do you know why it matters to get fit before knee surgery?
- What are the main early concerns on arriving home after surgery?
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What do you know about preventing thrombosis?
This is a complication that most people are warned about when signing up for knee surgery.
It is not that it is particularly common, but it can be pretty serious if it happens.
What do you think all this has done to the normal circulation of the leg?
A critical thing to know is that, although there is oxygenated blood being pumped out by the heart, there is no equivalent pump in the legs to return the blood. The legs rely on a series of valves in the veins that ensure that blood flows in only one direction, and it is the action of the leg muscles - the so-called ‘muscle-pump’ that forces the blood back to the heart. But your muscles have been kept still, even paralysed for a while, chilled, deprived of oxygen, and circulation is further compromised by cautery, dehydration, peripheral shutdown from being cold. The body does not know that this is all ‘elective’ and it responds as if your body has been assaulted - it tries urgently to heal. Red blood cells become more sticky, expecting to have to clot to close the wound. White cells migrate into the tissues expecting to remove germs. Chemicals cause local irritation so the tissues swell. So there is a lot going on, and not all of it good.
Helping your circulation after surgery
You are likely to have been given an injection before surgery to thin your blood, and tablets after surgery but you need to be an active participant in preventing this dreaded complication.
Get up and going as early as you are allowed - to get that muscle pump working again. When confined to bed, use those bed raisers to raise the foot of the bed. Wear your tight stockings to decrease the swelling and increase the pressure in the legs. Take the aspirin or other blood-thinner medication you may have been prescribed. And do foot-pump exercises whenever you can to get some muscle activity even while in bed.
Why does all this matter? Well, these first days are danger days for a blood clot in the leg veins - what we call a ‘thrombosis’ or ‘deep vein thrombosis’. Sometimes this is abbreviated to DVT. A problem is that little clots may shoot up into the heart and get stuck in the tiny vessels of the lungs, decreasing lung efficiency and compromising the heart’s attempts to oxygenate the blood.
Pulmonary embolus
The real danger, though, is of a large clot suddenly breaking free from the vein wall and shooting up into the lungs and blocking the vessels there to such an extent that the lung tissue itself is deprived of oxygen. This is called an embolus. The full medical name is pulmonary embolus or shortened to PE. This can be catastrophic and needs emergency attention, and can even result in sudden death. So the take-home message is that little steps can help to prevent a big catastrophe.
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