This is usually made worse if you have been particularly active during the day. The reason sleeping becomes an issue is that the lack of movement we do in bed causes stiffness in the joint. Once a joint is stiff, any small movements we do in adjusting our sleeping position become very painful. This wakes us up - often for only a few seconds as a quick bit of movement eases the pain - then back to sleep we go and the cycle repeats. In the early stages, many people don't wake enough to remember the episode and wonder why they are so tired the next day. As the pain and stiffness get worse the amount of movement required to ease the pain increases and movement as a remedy becomes less effective.
Medication becomes an important tool in these situations, as lack of sleep has an extremely negative effect on our mental well being. There is a reason sleep deprivation is used as torture.
What advice do I have to maximize sleep?
1) Firstly don't fall into the trap of doing less activity during the day in the hope of getting more sleep at night. This will lead to increased stiffness and a bigger problem.
2) Spend the time with your Doctor to find which drug or combination of drugs works for you. Due to our differing physical characteristics, certain drugs work better on some people than others.
3) Try using heat. Ice is used for acute sporting injuries but heat helps stiffness in chronic conditions. Many find that a nice hot bath or shower just before bed will increase the amount of sleep they get in before waking for the first time.
4) Some people find that the affected knee is very sensitive to light touch - especially from the occasional bump from the other knee. Try a pillow between the knees or a specifically designed pad if you tend to move about in your sleep.