A knee that hurts during the day can be managed: you change how you put weight on it, you get up, you move. At night you cannot: you stay still for hours in the same position, and that position decides how you wake up.
Why it hurts more at night
Three things that usually add up.
The movement is gone. During the day you walk, change position, and this distracts and keeps fluids moving. At night the knee stays where it is.
Fluid built up during the day tensions the capsule. If there is swelling, you feel it more when you stop: this is why many people feel worse in the evening and better in the morning.
The position pulls. Eight hours with the leg rotated inwards stretch the lateral structures; eight hours bent shorten them at the front.
The positions
On your side, the most used. Put the painful knee on top, with a pillow between your legs high enough to keep the thigh in line with the pelvis. Without a pillow the leg falls inwards and stays there all night: it is the most frequent cause of the lateral pain you wake up with.
If you feel better with the painful knee underneath, the pillow is still useful, so that the weight of the other leg does not rest on it.
On your back. People often feel better with a small support under the knee, which takes away tension. The important word is « small », and there is an exception worth reading before you do it: it is in the next paragraph.
On your front. This is the worst position for a painful knee: it keeps the leg straight and rotated, and allows no adjustment. If you have always slept this way, make the change to your side gradually, with a long pillow to lean against.
The mistake that costs you after surgery
A pillow under the knee gives relief. But after a knee replacement, after a cruciate ligament reconstruction, and whenever the aim is to regain full extension, that pillow works against you.
The reason is simple: a knee that spends eight hours bent every night loses extension, and extension is the hardest thing to get back. In those phases the right position is given by the person treating you, and it is usually the opposite of the most comfortable one.
If you are in that situation, the full pathway is in home exercises after knee replacement and in rehabilitation after the cruciate ligament.
The two hours before bed
They matter more than the pillow.
- Keep the leg raised for a while in the late afternoon, if there is swelling.
- Move during the day, in measured doses: total immobility stiffens the joint and does not reduce night pain.
- Ice can make falling asleep more tolerable, with a cloth between the ice and the skin, for a few minutes. Not all night, and it cures nothing.
- Avoid a long evening walk if you know you will pay for it the next day: the load is better spread across the day than concentrated at the end.
If the problem is not just the knee but sleep in general, we discuss it in sleep and recovery.
When night pain needs checking
Pain that depends on position is a problem of position. Pain that does not depend on position is something else, and it needs to be seen:
- it does not settle in any position;
- the knee is warm, red and very swollen, or there is a fever;
- it wakes you every night and gets worse week after week;
- it appeared after an injury.
The other signs that need a doctor first are in when it is not physiotherapy. If, on the other hand, the knee is warm and swollen without an injury, the picture is covered in a warm, swollen knee.
